for “Discovery of Natural Food for humans to attain Nibbana for
creation of Buddha the Awakened One with Awareness Universe” in 117
statue is built and stood at Koyasen University of Japan and Indian
Ambassoder at Japan is offering tribute to Babasaheb today for his 130th
birth anniversary
noted an impressive historical shift in the contents of the
scripturalcorpus in almost every Buddhist tradition. The early
Abhidharmas certainlyarose very early in an attempt to catalog and
systematize the Buddha’sconceptual vocabulary. Beyond this each tended
toward a speculativemetaphysics that eventually shifted away from the
Buddha’s focus onepistemology and toward ontological issues.72 in the
end with little concern forempirical reality.73 The canonical
Abhidharmas varied in how far they carriedthis trend, the Sarvastivadin
and its offshoot Vaibhāṣika sect going the furthestin its reification
of experience. The Theravada Abhidhamma was much morerestrained, but the
project deepened into the post-canonical commentarialperiod. It should
be noted that the Abhidharmas, unlike most innovations, werecertainly
not driven by popular concerns (these are difficult texts), but
byintellectual penchants of the scholarly monastics or most adept
Buddhists.Insofar as they deviate from Early Buddhism they represented
for the mostpart a distraction from the authentic Dhamma more than a
contradiction of it,producing a chubbier Buddhism that retains its
skeletal authenticity within.Nonetheless, this development is likely
also responsible for much unnecessaryearly Buddhist sectarianism. The
Mahayana movement represented a displacement of most of the
canonicalcorpora by new sutras as they came on line. Gombrich (1990)
suggests thatthis was facilitated by the circumstance that Buddhist
texts were nowappearing commonly in hard-copy rather than oral form,
which offeredopportunities for new or obscure texts to “go viral,” in
modern parlance(though “viral” here would describe, given the technology
of the time,dissemination in a matter of centuries rather than of hours
or days). Textswould not be so dependent as before on the editorial
influence of themonastics who had preserved scriptures through communal
recitation, and, asa result, the contents of such texts would have begun
to reflect increasingly thepractices and inclinations of the general
folk population rather than strictly theinterests of the most adept
members of the Sasana.
themes characteristic of the Mahayana included compassion, the
bodhisattva ideal, an elevated notion of buddhahood, a rejection of
thespeculative excesses of the Abhidharma projects and the doctrine
ofemptiness. Moreover, the mythical bodhisattvas and the fantastic
imageryassociated therewith provided many with a good read. Although the
earlydiscourses of the Buddha were available in Chinese translation, in
the Land ofthe Chopstick the study of the Mahayana sutras eclipsed that
of the earlydiscourses. Although the Mahayana sutras were new and not
early, that doesnot necessarily mean they were not, in our terms,
authentic. Aside from thoseof popular appeal, many of them developed and
clarified very sophisticatedand subtle core themes introduced in early
Buddhism with great skill.
most dominant theme to characterize the Mahayana is the
bodhisattvaideal. Early Buddhism embeds the life of the practitioner in a
greater epicstory, a path toward personal Awakening, toward becoming an
arahant, a paththat spans many lives of sincere practice. In the
Mahayana the storyline took abit different form: The Path now led toward
becoming a buddha, conceived asa far more exalted state. Entering the
path toward buddhahood one becomes abodhisattva, which is what the
Buddha is called in his previous lives asrepresented in the early Jataka
stories. As a bodhisattva one’s primary concernis the well-being of
others and one works for the Awakening of others as muchas for one’s own
Awakening.
bodhisattva ideal probably helped make lay practice more
respectful,given that the Buddha lived most of his previous human lives,
according to theJataka tales, as a layman, and yet was presumably
making respectful progresstoward buddhahood. Although the Mahayana
appears more lay-oriented thanthe early Buddhist sects, this is not to
say that Mahayana is a movementagainst monastic authority as many have
suggested. First, monastics havealmost always thrived in the Mahayana.
Second, it is now widely agreedamong scholars today that monastics, at
least those sympathetic to lay modesof practice, were the driving force
of the Mahayana and seemingly withoutexception composers of the Mahayana
sutras.74 Third, a shift in focus fromadept or monastic concerns toward
more folksy or lay concerns in theMahayana, may reflect a shift in the
means of preservation of texts – frommonastic recitation to writing
(with consequences for the kinds of texts thathave survived from
different eras) – as much as a shift in the contents of themix of
understandings actually current in Buddhist communities during
thedifferent eras.
any case, many of the Mahayana schools put more emphasis in their
textson common attainments than on the benchmark goal of Awakening. For
the\ most part these have to do with merit making towards ensuring a
felicitousrebirth or well-being in this life. Merit-making is already
present in earlyBuddhism, but innovations allowed transferring merit to
dead ancestors andtook to heart the care for the well-being of all
living thing, as emphasized inthe bodhisattva idea.
the singular goal of Awakening is rarely dismissed altogether infavor
of a common attainment, but is rather at worst put aside as
unattainable,either in practice or in principle. For instance, the
hugely popular Pure Landmovement is clearly oriented toward felicitous
rebirth, in fact, into a particularheavenly realm, the Pure Land. It
has, nonetheless, upheld the principle ofAwakening through most of its
history in allying itself, and sharing itsmonastics, with schools that
are more clearly oriented toward Awakening, forinstance in the common
modern syncretism of Pure Land with Ch’an inChinese temples. On the
other hand, other movements, such as NichirenBuddhism, assume we have
entered a degenerate age (Japanese, mappo) inwhich Awakening is
impossible in principle.
the benchmark goal of Awakening has generally held steady
historically,the common attainments and the mechanisms whereby they are
realized haveproven much more elastic. The common attainment of rebirth
in the PureLand, for instance, is facilitated by the power of the vow of
Amitabha, aBuddha who presides over the heavenly Pure Land and whose
past reserve ofmerit is readily shared with those who exhibit sufficient
devotion to Amitabha.This dependence on an external agent for salvation
contrasts rather markedlywith the Buddha’s early teachings. Subitism,
the doctrine sudden Awakeningmight also be mentioned in this regard.
Early Buddhism teaches a gradual Pathof progress toward Awakening, step
by step, with full attention toward allfoundations and requisites.
Sudden Awakening occurs quite spontaneously,often with little
preparation, like a lightning bolt, during meditation.
https://www.ncbi.nlm.nih.gov/books/NBK396513/
Might a Vegan Diet Be Healthy, or Even Healthier?
Publication Details
1. Introduction
Most great apes consume a wide variety of plant foods (Nestle 1999, 214; Milton 1999). The
Western lowland gorillas who live in the Central African Republic, for
example, have been observed to eat over 200 different plants and more
than 100 varieties of fruit (Popovich et al. 1997). Many of these plants foods are low in calories, so that the great apes must eat large quantities of them.
The
human ape is an exception. With the emergence of Homo erectus about 1.8
million years ago, a transition took place towards diets that were
nutritionally dense, which facilitated a significant expansion in brain
size (Leonard 2014). Another factor that facilitated a further increase
in brain size was the introduction of cooking about 250,000 years ago.
they started cooking, human beings benefited not only from easier
mastication, but also from a greater digestibility of, and an increase
in energy derived from, food (Carmody and Wrangham 2009). Whereas cooked
foods did not only include animal products, it is thought that our
gathering and hunting ancestors may have obtained more than half of
their daily energy from animal foods (Cordain et al. 2000; Mann 2000).
As animal foods provide more energy than plant foods per unit of weight,
this fact need not contradict what Nestle (1999, 215) has claimed,
namely that, up to when our ancestors started farming
about 10,000 years ago, there is ‘substantial support for the
predominance of plant foods in hunter-gatherer groups living in areas
where plants could grow’. Whereas no milk other than human milk may have been consumed before farming was introduced,
there is sufficient evidence to support the view that hunter-gatherer
societies consumed a greater proportion of animal foods than subsistence
farming communities later did (Leonard 2014): without modern
technology, it was difficult for most sedentary populations to adopt
dietary patterns that contained large quantities of animal foods.
Modern
science and technology have allowed many populations to become more
sedentary, to escalate the production of plant foods (through mechanical
and chemical agriculture), to use newly acquired genetic knowledge to
create modified feed crops and animal breeds in order to increase
the quantity of animal products, and to develop intensive production
systems of animal products (also known as factory farms or confined
animal feeding operations—‘CAFOs’) as well as refrigeration and modern
methods of transportation. Consequently, current diets of Western people
in particular tend to include large quantities of animal products.
These tend to be higher in total and saturated fats, as well as lower in
mono-unsaturated and n-3 fats, than the animal products consumed by
hunter-gatherer communities (Leonard 2014).
What
we are currently witnessing is the globalisation of this typical Western
diet through the influence of multinational corporations and of other
market forces such as the acquisition of new capital by many
populations, for example by many people living in China: until recently,
many Chinese people could not afford to eat many animal products on a
regular basis, and Chinese people were also much less exposed to the
economic and political influences of large agricultural corporations
that promote the consumption of such products. The recent increase in
the consumption of these products in China was also facilitated by
political shifts to a particular version of communism, followed by the
rise of capitalist ideology, both of which undermined Buddhist
questioning of such consumption. China’s neighbouring country, India,
has a long vegetarian tradition rooted in Hinduism and Buddhism, which
emphasises the principle of ahimsa (non-violence) and a reverence for
cows, in spite of the fact that some milk products have been consumed
for a long time—incidentally, not without controversy, as the
consumption of milk products was opposed by the Buddha’s cousin,
Devadatta (6th century BCE), and by those who followed his teachings
(Simoons 1994, 6,
. Like China, however, India is now moving rapidlyaway from its largely plant-based dietary tradition (Kasturirangan et
al. 2014).
Even if their number is rising, it is nevertheless
still the case that very few Western people adopt a vegan diet, and the
number of people elsewhere who adopt dietary patterns that are totally
or largely vegan is diminishing rapidly. There is no doubt that the
moral case against veganism would be strengthened if it could be shown
that vegan diets are unhealthy. Similarly, one might expect that the
moral case in favour of such diets would be stronger if it could be
shown that such diets are healthier than alternative diets. This is why I
shall explore the healthiness of vegan diets in this appendix. Unlike
in the main parts of this book, the concept of health is understood here
in a narrow sense: the pivotal question that will be addressed is
whether vegan diets are nutritionally adequate for those who adopt such
diets, irrespective of their healthiness for others.
Before
I embark on this task, it must be pointed out that any research into
the nutritional value of vegan diets is hampered by several problems.
One problem is the fact that many people who adopt these diets live in
countries (for example India) where little attention has been paid to
nutritional research, and few financial resources allocated to its
funding. Another is that many people have traditionally adopted vegan
diets out of necessity rather than out of choice. Up until recently for
most, and even today for some, people ate what they ate because they
lacked access to a diverse range of foods and, in many situations, found
it harder to obtain animal products than to obtain other food. If many
studied vegan populations adopt very restrictive diets because of
pressing personal, social, or ecological constraints, it will be easy to
find examples of deficient vegan diets, but much harder to find
convincing evidence of the nutritional adequacy of such diets. The
adoption of a very restrictive vegan diet may also be a symptom of a
food disorder, for example anorexia. A further problem is the existence
of a cultural bias against vegan diets (Sabaté 2003, 503S): as a result
of this bias, dominant factions of societies that possess financial
resources to study nutrition resist funding research that might
undermine the status quo.
In spite of these obstacles,
some research into the nutritional risks and benefits associated with
vegan diets has taken place; I shall first engage with the question
whether vegan diets could be healthy, and then move on to discussing the
question whether well-planned vegan diets might actually be healthier
than other diets.
2. Might vegan diets be healthy?
Many
nutritionists claim that vegan diets can be healthy; the American
Dietetic Association (ADA), for example, has argued that ‘appropriately
planned … vegan diets … are appropriate for individuals during all
stages of the life cycle’ (ADA 2009, 1266). To address this question in
detail, however, it is necessary to focus on those dietary components
that have frequently been suspected to be deficient in vegan diets. The
components that deserve special scrutiny are: protein, calcium, vitamin
B12, vitamin D, essential fatty acids, zinc, iodine, and iron.
Protein
Peas,
lentils, and beans are good sources of protein that are readily
available and relatively easy to grow in many parts of the world. It is
important that vegans consume protein foods that contain the full range
of essential amino acids overall; although there is no need for the full
range of essential amino acids to be part of every meal (ADA 2009,
1268; McEvoy and Woodside 2010, 87), it is clear that we do need all
essential amino acids to be healthy, which is why diets that rely on a
very limited range of protein sources must be avoided. Although concern
has been expressed over some populations that rely heavily on staples
with limited quantities of protein, such as taro, cassava, and yams,
Millward (1999, 259) has argued that ‘cereal-based diets, especially
those based on wheat and maize, supply protein levels considerably above
the requirement level’. However, there is no evidence to suggest that
those who consume relatively small quantities of cereals are likely to
have deficiencies, provided that they consume other foods that contain
significant quantities of protein. Overall, there is no evidence to
suggest that vegans who eat a good range of plant foods are likely to
lack in protein (Messina et al. 2004).
Calcium
Fruits and
vegetables that contain relatively large amounts of potassium and
magnesium decrease bone calcium resorption, whereas diets that include
relatively large amounts of nuts and grains increase such resorption by
producing a high renal acid load, mainly caused by residues of sulfates
and phosphates (ADA 2009, 1269). Green leafy vegetables that are low in
oxalate, including broccoli, kale, spring greens, and cabbage, tend to
be high in calcium, as well as in vitamin K, another important
contributor to bone health (Messina and Mangels 2001, 663). The study of
the Oxford-cohort of the European Prospective Investigation into Cancer
and Nutrition (the ‘Oxford-EPIC cohort’) found that adult vegans who
consume more than 525 mg of calcium per day do not show higher fracture
rates than omnivores (P. Appleby et al. 2007). There is no evidence that
well-planned vegan diets fail to provide sufficient calcium, but there
is evidence that diets that include adequate amounts of calcium and
vitamin D are protective of bone health (Tang et al. 2007).
Vitamin B12
No
plant foods are known to produce vitamin B12, or cobalamin, but those
who eat plants inadvertently eat B12 as this vitamin is produced by
micro-organisms (particularly Pseudomonas denitrificans and
Propionibacterium shermanii) who live in symbiosis with many plants. The
presence of vitamin B12 is essential for cell growth, and crucial for a
healthy nervous system. Vitamin B12 deficiency leads to elevated plasma
homocysteine (Hcy) concentrations (hyperhomocysteinaemia), a risk
factor for neurological disorders and cardio-vascular problems,
including pernicious anaemia and haematological disease (megaloblastic
anaemia with demyelination of the central nervous system) (McEvoy and
Woodside 2010, 90; Waldmann et al. 2005). Whereas our intestinal
bacteria can synthesise B12, it is generally assumed that we should also
consume products containing B12 (Li 2011).
Some studies have
found that some vegans had inadequate intakes of B12, where particular
concerns have been raised over the B12 status of older people due to
their limited absorption capacity and of pregnant women due to their
higher demands (Majchrzak et al. 2006; Waldmann et al. 2005; Donaldson
2000; ADA 2009; Piccoli et al. 2015). This is not a reason to eat flesh,
as B12 binds with the protein in animal foods, impeding absorption,
which is precisely why older people are better off with vegan sources of
B12 (Norris and Messina 2011, 31). Since the haematological symptoms of
vitamin B12 deficiency may go undetected for a long time due to a high
consumption of foods containing folate (folic acid), of which many
vegans consume rather a lot through the consumption of things like
oranges, green leafy vegetables, and beans, vegans must be very careful
to ensure that their consumption of B12 is sufficient (ADA 2009, 1269).
Many products, including cereals and yeast extracts, now exist that have
been fortified with B12 produced through industrial fermentation of
bacteria. In his assessment of the evidence, Sanders (1999, 267) has
written that, provided that ‘these foods are consumed regularly, the
hazard of vitamin B12 deficiency is easily avoided’.
Norris and
Messina (2011, 32) usefully point out that the human body only absorbs a
tiny amount of B12 every time the vitamin is consumed, which is why
they recommend the adoption of any one of these strategies for optimal
consumption: 1/ two daily servings of fortified foods, providing 1.5 to
2.5 micrograms each; 2/ one daily supplement of at least 25 micrograms;
3/ one supplement of 1,000 micrograms twice weekly.
Vitamin D
Inadequate
levels of vitamin D have long been known to contribute to bone problems
such as rickets, but more recently have also been found to contribute
to a range of other conditions, including fibromyalgia, rheumatoid
arthritis, multiple sclerosis, depression, cancer, hypertension, and
diabetes (Norris and Messina 2011, 47). Adequate exposure to sunlight
can provide the body with all the vitamin D it needs, but overexposure
must be avoided as ultraviolet irradiation is a significant contributor
to skin cancer. Those people who are not regularly exposed to sunlight,
as well as those whose bodies are limited in the uptake of vitamin D,
such as older and dark skinned people, must therefore consume products
that have been fortified with vitamin D or take supplements (Craig 2009,
1629S; Stacey et al. 2005, 1444; Holick 2007). Vitamin D3
(cholecalciferol), used as a supplement, is usually derived from lanolin
(sheep’s wool) or fish oil, and is also found in some lichen and
extracted from them by some companies, but the consumption of vitamin D2
(ergocalciferol)—produced from the ultraviolet irradiation of
ergosterol from yeast—has been shown to be as effective in providing the
human body with vitamin D (Holick et al. 2008).
Plasma
25-hydroxyvitamin D concentrations were measured in 2,107 participants
of the Oxford-EPIC cohort, showing that vegans had lower concentrations
of vitamin D, particularly during the winter months (Crowe et al. 2010).
Whereas most participants in this study had concentrations that were
deemed to be adequate, it is nevertheless very important to recognise
that many people who live far away from the equator and who do not
expose themselves frequently to sunlight (because of spending much time
indoors and clothing) fail to meet recommended levels. This may be why
Craig (2009, 1630S) has expressed the view that a daily supplement of
5–10 micrograms of vitamin D would be ‘highly desirable for elderly
vegans’; however, some recent studies suggest that a higher dosage may
be required to maintain optimal blood levels, which is why Norris and
Messina (2011, 47) recommend 25 micrograms or 1,000 International Units
(IUs) daily for people who do not benefit from adequate sun exposure.
Essential fatty acids
Omega-3
(or n-3) and omega-6 (or n-6) fatty acids are widely regarded to be
beneficial for human health. The two most important ones of these are
two short-chain polyunsaturated fatty acids: α-linolenic acid (ALA),
which the body can use to create other fats within the n-3 fatty acid
family, and linoleic acid (LA), which the body can use to create other
fats within the n-6 fatty acid family. These two fatty acids are called
‘essential’ because they cannot be synthesised by the human body, but
are required for healthy functioning. They must therefore be supplied by
our diets. Enzymes in our bodies convert these short-chain fatty acids
to long-chain n-3 and n-6 polyunsaturated fatty acids. ALA is converted
(incidentally, not only by humans, but also by many other animals,
including fish) to eicosapentaenoic acid (EPA), docosahexaenoic acid
(DHA) and docosapentaenoic acid, with stearidonic acid (SDA) as an
intermediate in the pathway; LA is converted to arachidonic acid
(Saunders et al. 2012a).
The palaeolithic diets that were adopted
by hunter-gatherers are estimated to have had an n-6:n-3 ratio of 1:1
to 2:1. Many people who live today, by contrast, overconsume LA (C.
Williams and Burge 2006). The n-6:n-3 ratio of typical Western diets has
been estimated to be around 15:1 to 17:1 (O’Neill 2010, 200). This is a
serious problem, as overconsumption of LA impairs ALA conversion. Many
people also underconsume ALA, which may cause deficiencies in the
particularly important EPA and DHA (B. Davis and Kris-Etherton 2003).
High intakes of trans-fatty acids, alcohol, and caffeine, as well as
imbalanced diets and illness in general, may produce the same
deficiencies in EPA and DHA. Such deficiencies are believed to cause
cardio-vascular disease and cancer, as well as exacerbated pain
associated with a range of conditions (Simopoulos 2002; von Schacky
2009; Christophersen and Haug 2011). They may also cause cognitive
decline, age-related macular degeneration, and depression (Saunders et
al. 2012a, 24S).
A clear message emerges from this. Vegans must
make sure to consume adequate amounts of ALA, and avoid high consumption
of products that inhibit the conversion of ALA, including products that
contain relatively large quantities of LA. Accordingly, a recent study
recommends that at least one unit of n-3 be consumed for every four
units of n-6 (Saunders et al. 2012a, 24S). The authors of the study also
recommend an ALA intake of 2.6 g/day for men and 1.6 g/day for women,
whilst recommending the following daily intakes for infants and
children: 0.5 g at 0–6 months; 0.5 g at 7–12 months; 1 g for children
aged 1–3; 1.6 g for children aged 4–8; 2 g for boys aged 9–13; 2.4 g for
boys aged 14–18; and 1.6 g for girls aged 9–18 (Saunders et al. 2012a,
24S). The main reason for the gender differences relates to the fact
that males tend to convert ALA less efficiently (Childs et al. 2008).
Plant
foods that are high in omega-3 fatty acids include chia, flax, canola
(rapeseed), hemp, walnuts, perilla, and olive oil (Saunders et al.
2012a; O’Neill 2010, 201). Blackcurrant seed oil, derived from the seeds
of Ribes nigrum, is rich not only in omega-3 fatty acids, but also in
SDA, and the same applies to oil derived from plants belonging to the
Echium genus, a collection of species within the Boraginaceae family (Li
2011). Genetically engineered soybeans that contain SDA have also been
recommended (Saunders et al. 2012a), but their inclusion within a diet
would depend on their acceptability, a debate that I touched upon
briefly in section 2.11 and that I shall not engage with any further
here. To ensure adequate consumption of ALA, Norris and Messina (2011,
89) recommend that adults consume three to four daily servings from this
list: ‘1 teaspoon canola oil, 1/4 teaspoon flaxseed oil, 2/3 teaspoon
hempseed oil, 1 teaspoon walnut oil, 2 teaspoons ground English walnuts
or 2 walnut halves, 1 teaspoon ground flaxseeds, 1/2 cup cooked
soybeans, 1 cup firm tofu, 1 cup tempeh, 2 tablespoons soynuts’.
People
with increased needs (for example pregnant and lactating women) and
people with compromised conversion rates (for example people with
diabetes or hypertension, and older people) may also benefit from
consuming limited amounts of DHA- and—where available—EPA-fortified
foods and DHA-supplements derived from microalgae (which can
retro-convert to EPA inside the human body), as well as from consuming
brown algae (kelp) oils (Saunders et al. 2012a; ADA 2009, 1268, 1271;
Craig 2009, 1629S; Geppert et al. 2005). Norris and Messina (2011, 58,
55) write that vegans over the age of 60 ‘should consider’ a daily DHA
(or a combination of DHA and EPA) supplement of 200 to 300 milligrams, a
supplement dose that they are also ‘inclined to recommend’ at a
frequency of every two to three days for those who are younger.
Although
it may be unlikely to happen, overconsumption of DHA-rich products must
be avoided, as this may raise total and low density lipoprotein (LDL)
cholesterol, cause prolonged bleeding, and reduce immunity (Craig 2009,
1629S; Geppert et al. 2005; Sanders et al. 2006).
Zinc (Zn)
Provided
that it is present in the soil, many plant foods contain zinc. Plants
that tend to be high in zinc are cereals and legumes. Unrefined whole
grains provide higher concentrations than refined grains, as zinc can be
found particularly within the outer layer of grains (Saunders et al.
2012b, 17S). Various ways to increase zinc uptake have been described,
including soaking and sprouting beans, seeds, and grains, as well as
leavening bread and consuming foods that contain citric acids (Lönnerdal
2000). Zinc absorption can be reduced by phytates (phytic acids),
protein, and insoluble fibre, as well as by some minerals, including
iron, calcium, and potassium (Li 2011). Whereas whole grains are higher
in phytates than refined grains, the relative greater effect of phytates
in the former is more than compensated for by the fact that whole
grains are higher in zinc (Messina and Mangels 2001, 664). A study that
compared 25 vegans with 20 omnivores found that the inhibitory effect of
phytate failed to compromise zinc status as the bodies of people who
take in little zinc appear to be able to increase zinc absorption and
retention (Haddad et al. 1999).
As an aside, whereas it is good
to be mindful that potassium may inhibit the absorption of zinc, it is
nevertheless important to secure a sufficient intake of potassium as
well. The following are listed as good sources of potassium by Norris
and Messina (2011, 76): beet greens, spinach, Swiss chard, cooked
tomatoes and tomato juice, bananas, sea vegetables, orange juice, and
legumes.
Iodine
Iodine deficiency affects more than two
billion people. It is the leading cause of preventable mental
retardation worldwide. Foetuses and breastfed children are particularly
vulnerable as they depend on maternal iodine intake for thyroid hormone
synthesis, which is essential for human neurological development.
Thyroid iodine uptake is inhibited by perchlorate—an ubiquitous
environmental contaminant—cigarette smoke, cruciferous vegetables (of
the family Brassicaceae), and seaweeds of the genus Laminaria (including
kombu) (Leung et al. 2011, e1304; Lightowler 2009, 433–434); there is
also concern over the inhibitory effects of particular isoflavones found
in soya and flaxseed. Both the underconsumption and the overconsumption
of iodine can cause goitre (an enlargement of the thyroid gland) and
hypothyroidism, but the latter can also cause hyperthyroidism (Norris
and Messina 2011, 70–71). A small American study found, however, that in
spite of the fact that a cohort of Boston-area vegans had relatively
low urinary iodine levels, these low levels were not associated with
thyroid dysfunction (Leung et al. 2011).
Provided that they have
access to adequate nutrition, vegans should not suffer from iodine
deficiencies. Iodine can be provided through plants grown on iodine-rich
soil, the consumption of seaweed, and the consumption of iodised salt.
As levels of iodine in seaweed vary considerably and are therefore
unreliable, and as the overconsumption of salt must be avoided, Norris
and Messina (2011, 72, 89) recommend the use of supplements as their
favourite strategy, where their recommendation for adults is that they
take supplements of 75 to 150 micrograms three to four days per week in
order to meet a recommended daily allowance of 150 micrograms, whereas
lower levels of 90 micrograms daily are recommended for very small
children and higher levels of up to 290 micrograms daily for lactating
women. They also recommend one quarter of a teaspoon of iodised salt per
day as an alternative to supplementation. The development of a global
strategy to ensure routine, adequate iodisation of foods which are
commonly used that guards at the same time against excess intake of
iodine, which negatively affects the thyroid gland (Lightowler 2009,
431), would seem to be appropriate in view of the scale of the problem
of iodine deficiency. Some localities have already developed guidelines;
in the USA, for example, vegan pregnant and lactating women have been
recommended to supplement their diets with 150 micrograms of iodine
daily (Leung et al. 2011, e1303).
Iron
Foods contain iron
in two forms: haem iron and non-haem iron. Vegan foods only contain the
latter, which is less easily absorbed by the body. Whereas iron
deficiency can be a problem for vegans, it is more likely to be a
problem for omnivores who consume large quantities of milk than for
diet-conscious vegans. Good vegan sources of iron are dried fruit, sea
vegetables, leafy green vegetables, and beans (Norris and Messina 2011,
64, 70). Vegans who consume a good range of fruit and vegetables in
addition to foods that contain relatively large amounts of iron are
unlikely to be affected by a deficiency as many fruits and vegetables
contain large quantities of vitamin C, as well as other organic acids,
which enhances iron absorption. Retinol, carotenes, and alcohol have
also been reported to increase iron absorption, whereas inhibitors
include oxalates, phytates, and calcium, as well as the polyphenolics
that are present in tea, some herbal ‘teas’, coffee, and cocoa (Ma et
al. 2005; Siener et al. 2006; Hallberg and Rossander 1982; Li 2011;
McEvoy and Woodside 2010, 88; ADA 2009, 1268). It is for this reason
that Norris and Messina (2011, 70) recommend that people who drink tea
and coffee only do so between meals rather than with their meals. As low
iron status is moderately common in premenopausal women, these women
need to make sure that their diets include good sources of iron,
together with vitamin C to aid absorption (Key et al. 2006, 37). At the
same time, there is evidence of the human body’s ability to adapt to low
iron intake by increasing absorption and decreasing losses (Hunt and
Roughead 1999; Hunt and Roughead 2000).
Taking stock
The
account presented above shows that vegan diets can fulfil all the
nutritional requirements that are needed to support good health.
Nutrients that present particular concerns are vitamin B12 and omega-3
fatty acids as few vegan foods that are currently used for human
consumption contain these. Accordingly, vegans must make sure that they
consume adequate portions of such foods. A nutrient that I have not
mentioned, but that may be a concern, is selenium (Norris and Messina
2011, 76): as the selenium content of soil varies across the world,
vegans must ensure that they do not restrict their diets to foods that
are grown on soils that have low selenium levels. All in all, vegan
diets can be adequate for all human beings, including children. Although
small children with reduced stomach capacities may need to eat
regularly and must ensure that they eat foods that are sufficiently high
in energy density to provide sufficient calories, that are relatively
easy to digest (for example by including cooked rather than raw foods),
and that are not excessive in fibre (Messina and Mangels 2001, 662),
many nutritionists adopt the view that vegan diets can be adequate for
all human beings (Messina and Mangels 2001; Norris and Messina 2011; Van
Winckel et al. 2011; ADA 1997).
3. Might vegan diets be healthier than other diets?
The
claim has also been made that well-planned vegan diets may be healthier
than other diets (Norris and Messina 2011, xv; B. Davis and Melina
2014, 29). It is this claim that I shall explore in the remainder of
this appendix. One way in which this claim could be examined is by
focusing on mortality differences between vegans and others. The
problem, however, is that no studies exist of populations where
omnivores share similar genetic profiles, similar lifestyle patterns,
and similar social and environmental factors with a significant number
of vegans. Nevertheless, a meta-analysis of seven prospective cohort
studies—that is, studies which compare, usually over a long time, those
who remain healthy with those who become ill—from the UK, Germany,
California, the USA, the Netherlands, and Japan, including 124,706
participants, compared vegetarians with omnivores and found that
all-cause mortality was 9% lower amongst vegetarians (T. Huang et al.
2012).
Whereas the fact that vegetarians benefit from increased
longevity does not imply that this would also be the case for vegans,
there is evidence that people who consume large quantities of fruits and
vegetables—foods that tend to be more prominent in vegan diets—live
longer than those who do not do so. Some evidence for this is provided
by a Finnish study of 2,641 men who were aged between 42 and 60 and
whose diets were assessed by four-day food intake records between 1984
and 1989. With a mean follow-up time of nearly 13 years, the study found
that, after adjustment for major risk factors for cardio-vascular
disease, those within the highest fifth for intake of fruits (including
berries) and vegetables had a relative risk for all-cause death that was
34% lower than that of those in the lowest fifth (Rissanen et al.
2003). Several other studies found a positive association between diets
that are relatively high in the consumption of fruits and vegetables,
such as the traditional Mediterranean diet of people who lived in Pioppi
(Italy) up to about four decades ago, and a reduction in mortality
(Keys 1995; Benzie and Wachtel-Galor 2010). As diets that include a
large proportion of fruits and vegetables have been shown to be
healthier than diets that include relatively few of these foods, it has
been estimated that a large number of premature deaths could be
prevented amongst populations that consume large quantities of animal
products by increasing the consumption of plant foods (Scarborough et
al. 2012a).
In the remainder of this appendix I shall focus on
studies that provide evidence for a difference between vegan and other
diets in relation to the morbidity factors of obesity, bone health,
cardio-vascular disease, diabetes, cancer, diverticular disease,
Parkinson’s disease, and insulin-like growth factor 1 (IGF-1) and mTORC1
related diseases.
Obesity
Several studies have shown that
vegan diets are associated with a reduced incidence of obesity as they
tend to include fewer trans-fats (which are found mainly in processed
foods with partially hydrogenated fats), fewer saturated fats (which can
also be found in fully hydrogenated vegetable oils), and more dietary
fibre (Rizzo et al. 2013; ADA 2009, 1274; McEvoy and Woodside 2010, 84;
Spencer et al. 2003; Davey et al. 2003; Haddad et al. 1999). Obesity is a
known risk factor for a wide range of health conditions, including
cardio-vascular disease, type 2 diabetes, some cancers, and
dyslipidaemia (WCRF/AICR 2007, 374–376). In addition, HIV patients may
avoid or reduce lipodystrophy problems by adopting vegan diets (McCarty
2003b). In recent years, many companies in the dairy industry have
responded to the challenges associated with rising rates of obesity by
producing and promoting low fat alternatives. In spite of the reduction
in fat, these products still contain large amounts of calories that are
turned into fatty tissues if they are surplus to human energy
requirements, thus contributing to increases in weight (Lanou 2009).
Bone health
The
Oxford-EPIC study found that UK vegans had a 30% increase in fractures
compared to other dietary groups in the UK and that 45% of the vegan
group consumed less than 525 mg of calcium per day, compared to only 6%
in the other dietary groups (P. Appleby et al. 2007). When vegans whose
consumption averaged more than 525 mg of calcium per day were compared
with other groups, however, fracture rates in this specific vegan group
were about the same as those in the other groups.
Cows’ milk is
frequently recommended for bone health. However, in a study of 72,337
postmenopausal women that followed up participants for hip fractures for
18 years, it was found that neither a high calcium diet nor cows’ milk
consumption was associated with a reduced risk of hip fracture
(Feskanich et al. 2003). An earlier, retrospective study found that hip
fractures are higher in countries with high protein consumption from
animal products (Abelow et al. 1992).
This finding tempted Lanou
(2009, 1639S) to speculate that high consumption of animal products may
undermine bone health. For three reasons, it is hard to conclude this
from the Abelow et al. (1992) study. Firstly, the study estimated
protein consumption for whole populations, rather than for the study
groups; estimated intakes of animal protein may therefore differ greatly
from what those who suffered hip fractures actually consumed. Secondly,
the interpretation ignores that many countries where relatively large
quantities of animal products are consumed tend to have high life
expectancies (Kannus et al. 1996); the fact that rates of hip fractures
are higher in countries where lots of animal products are consumed may
therefore simply be explained by the fact that life expectancies are
higher within those countries. Thirdly, the possibility that cultures
that rely heavily on animal products may have different lifestyle
factors that contribute to fracture risks should not be ignored (Calvez
et al. 2012).
In spite of these reservations, limited evidence in
support of Lanou (2009)’s hypothesis comes from a more recent,
prospective study, which is interesting as it makes a direct comparison
between fracture rates and bone mineral density loss in vegans and
omnivores. The study, which took place in Ho Chi Minh City (formerly
Saigon), compared the rate of femoral neck bone mineral density loss and
morphometric vertebral fractures of 88 vegan and 91 omnivorous women
over the age of 50 two years after baseline measurement. Groups were
matched at baseline, but the vegans had significantly lower dietary
intakes of calcium and vitamin D, as well as of total protein and fats.
In spite of their lower consumption of calcium and vitamin D, this study
found that there was no difference in fracture rates between vegans and
omnivores, but that ‘higher intakes of animal protein and lipid’ (fat)
were associated with greater bone loss (Ho-Pham et al. 2012, 75), a
finding that the authors relate to earlier research that attributes a
causal role in bone loss to the presence of high levels of acid in
animal protein (Barzel and Massey 1998). Given the small number of
participants that were involved and the specific genetic, cultural, and
environmental context, it is not possible, however, to conclude that
vegans are more likely to have healthier bones that are less prone to
fractures than omnivores.
Further research has also revealed that
high consumption of protein may be a risk factor for fractures not per
se, but only when it is combined with low consumption of calcium
(Burckhardt 2013). On the other hand, through increased consumption of
fruits and vegetables, vegans tend to have a lower renal acid load,
which reduces urinary calcium excretion and bone resorption (New 2003).
In this respect, high consumption of vegetables and fruits with high
potassium, magnesium, and vitamin K contents may be particularly
desirable (Calvez et al. 2012; Tucker et al. 2001; Booth et al. 2000;
Feskanich et al. 1999). A further reason why vegans may be protected
relates to the fact that vegans do not consume preformed vitamin A,
which is known to cause a reduction in bone mineral density if it is
consumed in large amounts (Burckhardt 2015).
Whereas bone health
is not necessarily undermined by low calcium intakes, it must be
emphasised that calcium is the main mineral in human bones. Adequate
consumption of calcium is one factor that contributes to good bone
health, even if it does not guarantee it as the rate at which calcium is
absorbed is determined largely by other dietary factors. One of these
factors is vitamin D status, the importance of which was highlighted
earlier. Another is adequate protein consumption. The importance of the
latter is borne out by a study of 1,865 women from Canada and the USA
who were followed up over 25 years, where, of the 40% who adopted a
vegetarian diet, those with the highest protein consumption had the
lowest risk of wrist fractures (Thorpe et al. 2008).
Cardio-vascular disease
Cardio-vascular
diseases are the most common causes of mortality. Most cardio-vascular
diseases result from venous or arterial blockages (thrombosis). These
occur by a rupture of atherosclerotic plaque and result in tissue damage
from blood starvation. Cerebrovascular and ischaemic heart diseases are
the two most common types of cardio-vascular disease.
A
meta-analysis that included 124,706 participants recruited for seven
prospective cohort studies that compared vegetarians with omnivores in
the UK, Germany, California, the USA, the Netherlands, and Japan found
that vegetarians had a 29% lower mortality risk for ischaemic heart
disease (T. Huang et al. 2012). This is in line with findings from a
meta-analysis of five prospective studies that compared data for 76,172
people from Germany, the UK, and the USA, which found that the mortality
rate from ischaemic heart disease was 24% lower in vegetarians than in
non-vegetarians after a mean follow-up of just over ten years and a half
(Key et al. 1999). Although the death rate for ischaemic heart disease
was slightly higher for the vegans than for the vegetarians in this
latter meta-analysis, the risk ratio for death from cerebrovascular
disease for vegans was only about half that for those who ate animals’
flesh at least once a week.
Two large, and ongoing, cohort
studies in particular have been widely reported with regard to
diet-associated cardio-vascular disease risk. The first is the
Oxford-EPIC study; the second a study (‘the AHS-2 study’) from the USA
and Canada with a cohort of 73,308 Seventh-day Adventists who were
recruited at churches between 2002 and 2007 and followed up over more
than five years (Orlich et al. 2013).
The Oxford-EPIC study has
documented that self-reported hypertension was lowest amongst vegans,
whilst a study of blood pressure in a sub-cohort of 8,663 participants
who reported not to suffer from hypertension found that the 612 vegans
in that sub-cohort showed lower systolic and diastolic blood pressures
than people in any other dietary category in that sub-cohort, which
could only partly be attributed to differences in body mass, i.e. the
fact that the vegans tended to be leaner (P. Appleby et al. 2002). In
2013, the authors of the study reported that a vegetarian group (which
included vegans), which comprised 34% of a total sub-cohort of 44,561
people living in England and Scotland, had a 32% lower risk of ischaemic
heart disease after a follow-up of just over 11 years than the
omnivores in the same sub-cohort when adjustment for all confounding
factors apart from body mass index (BMI) was performed, and a 28% lower
risk when BMI was factored in (Crowe et al. 2013).
Similar
findings are reported in the AHS-2 study (Orlich et al. 2013). Compared
to the group of omnivores, deaths from ischaemic heart disease and
cardio-vascular disease were, respectively, 10% and 9% lower amongst the
group of 3,533 ‘vegan’—defined here as those who reported to consume
animal products less than once a month—women, whereas the group of 2,015
‘vegan’ men experienced risk reductions of, respectively, 55% and 42%.
For a sub-group of this cohort, comprising 500 white subjects, it was
found that the group of 49 ‘vegans’ had a 63% lower risk of suffering
from hypertension (where someone suffering from hypertension was defined
as someone who either took medication for it or someone who had a
systolic blood pressure exceeding 139 mmHg or a diastolic blood pressure
exceeding 89 mmHg), which was only partly accounted for by differences
in body mass (where ‘vegans’ tended to be leaner) (Pettersen et al.
2012).
Whereas the Oxford-EPIC and the AHS-2 studies concern
Western populations, similar results were obtained in a Chinese study,
where healthy men who consumed no animal products other than milk were
found to have lower risks of cardio-vascular disease than omnivorous men
(Yang et al. 2012).
Why is it that vegans may be less prone to
cardio-vascular disease than omnivores? Both obesity and hypertension
may play a role in this difference, as both high BMI and high blood
pressure have been associated with elevated risk. Another reason relates
to levels of cholesterol. Low density lipoprotein (LDL) and high
density lipoprotein (HDL) are the main cholesterol components that are
found in our blood; a low level of the former and a high level of the
latter are generally thought to benefit cardio-vascular health. LDL can
oxidise, promoting plaque formation and hardening of the arteries, but
this can be undermined by high levels of HDL. Vegan diets may protect
against cardio-vascular disease because they do not contain animal
products, which tend to be relatively high in substances that elevate
LDL cholesterol, including total and saturated fat (Fung et al. 2010;
Bernstein et al. 2010; Norouzy et al. 2011). Vegan diets are also
generally higher in fibre, which has been found to reduce LDL
cholesterol (Jenkins et al. 2001). In relation to this, research has
found that the consumption of whole grains, which—unlike refined
grains—include the bran, germ, and endosperm, and are relatively rich in
fibre, reduces cardio-vascular risk factors (Liu et al. 1999; Park et
al. 2011). Vegan diets also tend to be relatively low in bio-available
phosphate, where high phosphate levels are associated with increased
risk (McCarty 2003a). Vegans must be careful, however, to avoid
overconsumption of refined carbohydrates (as for example white-flour
products, white rice, and sugar), as this reduces HDL, which removes
excess LDL cholesterol from the bloodstream (O’Neill 2010, 202–203). As
mentioned before, they must also be careful to maintain adequate levels
of vitamins B12 and D, as well as a good balance of n-6 over n-3 fatty
acids, as deficiencies in these domains have been associated with
elevated risks of cardio-vascular disease (Li 2011; Woo et al. 2014;
Bouillon and Verlinden 2014).
Vegans may benefit not only from
lower LDL levels, but also from the fact that they tend to remove
detrimental components (‘atherogenic remnants’) more quickly from the
blood (Vinagre et al. 2013). In addition, several studies have
associated reduced risks of cardio-vascular disease with high intakes of
fruits, vegetables, and nuts (Finks et al. 2012; Takachi et al. 2008;
He et al. 2006; Mozaffarian et al. 2011; Hu 2003; Jenkins et al. 1997;
Sacks et al. 1999). This stems at least in part from the fact that diets
that are high in nuts and in plant sterols are known to reduce total
and LDL cholesterol levels (Katan et al. 2003; Mukuddem-Petersen et al.
2005; Sabaté et al. 2010).
Diabetes
Although some studies
have linked the development of type 1 diabetes to the consumption of
dairy products (Dahl-Jørgensen et al. 1991; Banwell et al. 2008), a
meta-analysis of studies pointed out that no causal link has been
established (Agostoni and Turck 2011). However, a more recent study
suggests that consumption of cows’ milk very early in life may trigger
type 1 diabetes if it is accompanied by exposure to enterovirus
infections in early life (Lempainen et al. 2012).
More evidence
exists on the positive benefits of vegan diets for the prevention and
treatment of type 2 diabetes, as well as of the associated
cardio-vascular diseases (Kahleova and Pelikanova 2015; Tonstad et al.
2009; Marsh and Brand-Miller 2011; Salas-Salvadó et al. 2011). As weight
is a major risk factor for the development of this condition, vegans
are less likely to develop type 2 diabetes because of their lower weight
(Fung et al. 2004; Trapp and Levin 2012). However, several studies show
that there are other factors why vegan diets may prevent type 2
diabetes, such as the fact that no red and processed flesh is consumed,
and that more whole grain foods and nuts may be consumed, all of which
factors have been associated with reduced diabetes risk (Pan et al.
2011; Marsh 2011).
Vegan diets have also been shown to help in
the treatment of type 2 diabetes by lowering total and LDL cholesterol
and by controlling lipid levels, for example by reducing triglycerides, a
type of fat that is also associated with a greater risk of heart
disease (Jenkins et al. 2006; Barnard et al. 2006; Barnard et al. 2009,
1594S; Tonstad et al. 2009; Vinagre et al. 2013). Many vegan diets have a
low glycaemic index (GI) and a fairly low glycaemic load. The GI is a
measure of the effect of carbohydrate-containing foods on blood glucose
response (i.e. how quickly the body converts carbohydrates into energy)
after their consumption (Jenkins et al. 1981), and the glycaemic load is
the product of the amount of foods consumed and their glycaemic index
(Finks et al. 2012, e70). People who consume large quantities of foods
that have a high GI are thought to be at increased risk not only of
diabetes and cardio-vascular disease, but also of a number of
conditions—sometimes grouped under the label of ‘metabolic
syndrome’—including obesity, hypertriglyceridemia, and low HDL
cholesterol (Finley et al. 2010; Ludwig 2002; Finks et al. 2012). It has
also been found that obesity reduces tolerance of diets with high
glycaemic load (Liu et al. 2000). In relation to diabetes, diets with
high GI values are associated with greater insulin resistance and a
greater incidence of hypoglycaemia amongst those who are treated with
insulin (Willett et al. 2002; Ebbeling et al. 2007).
In a
randomised controlled trial of a duration of five months, whereby 99
people with diabetes were divided into a group of 49 who were asked to
follow a vegan diet and a group of 50 who were asked to follow a diet
recommended by the American Diabetes Association, the overall GI of the
vegan group’s diet was significantly lower than that of the other
group’s diet (Turner-McGrievy et al. 2011). The associated reduction in
body weight, together with the reduced fat content (and the associated
reduction in intramyocellular lipid—a contributor to insulin resistance)
and increased fibre content of the vegan diet, was thought to result in
better glycaemic control (Turner-McGrievy et al. 2011, 1472). The vegan
group also managed to reduce their medication significantly more than
those who belonged to the other group, a significant finding in light of
the fact that some hypoglycaemic drugs contribute to weight gain
(Barnard et al. 2006; Barnard et al. 2009). All this does not imply that
one’s dietary glycaemic index is necessarily lowered by the adoption of
a vegan diet, as Norris and Messina (2011, 185) rightly point out that
‘the key is to choose carbohydrate-rich foods with low GIs, which means
eating more unprocessed, whole plant foods in place of refined
carbohydrates’.
Cancer
It is highly probable that many
vegan diets are less likely to cause cancer than other diets are. The
Oxford Vegetarian Study and the Oxford-EPIC study provide evidence for
this claim (Key et al. 2009a). The former study recruited 11,140
vegetarian and non-vegetarian participants throughout the United Kingdom
between 1980 and 1984. The latter study recruited a much larger number
of participants between 1993 and 199, and is part of a much larger,
multicentre, prospective study with 519,978 subjects overall, carried
out in 23 centres from 10 European countries (Denmark, France, Germany,
Greece, Italy, the Netherlands, Norway, Spain, Sweden, and the United
Kingdom). Data from the Oxford Vegetarian Study and the Oxford-EPIC
study were combined, resulting in a cohort of 61,566 people (15,571 men
and 45,995 women) who were followed up to 2007; participants were
separated into three dietary groups on the basis of their answers to
four questions, collected by means of an intake questionnaire: 32,403
omnivores, 8,562 fish eaters (who did not eat any other animals’ flesh),
and 20,601 vegetarians (Key et al. 2009a).
Before looking at the
evidence of this combined study, it must be recognised that this study
is not free from methodological concerns. Since it is a longitudinal
study, it is quite possible that dietary patterns varied significantly
over the large number of years that participants were followed up. A
second problem is that actual diets may differ from reported diets. From
a personal lunch-time conversation with a participant in the EPIC
study, I found out, for example, that he had chosen the vegetarian
group, whereas he actually ate fish. A third problem is that the more
subtle distinctions between the kinds of foods that people eat are
ignored by the fact that the questionnaire only aimed to distinguish
between three dietary categories, omitting a vegan diet category. A
fourth problem is that participants appeared to be particularly health
conscious whichever diet they adopted, as death rates were significantly
lower (at 52% of the general population’s death rates in the
Oxford-EPIC study) than that in the general British population (Key et
al. 2009b). These problems impair the ability to generalise results from
this study group to other people.
In spite of these
difficulties, it is significant that the study found that the overall
cancer incidence amongst vegetarians was about 12% lower than the
incidence amongst omnivores (Key et al. 2009a), which is in line with
the 18% reduction that was found in a recent meta-analysis of seven
prospective cohort studies that compared vegetarians with omnivores in
the UK, Germany, California, the USA, the Netherlands, and Japan (T.
Huang et al. 2012). The combined Oxford study found lower incidences in
the vegetarian group for ovarian and bladder cancers, as well as for
cancers of the lymphatic and haematopoietic tissues and for stomach
cancers (of which there were only 49 cases), but the risk of cervical
cancer—of which there were only 50 cases—was more than twice as high in
the vegetarian group than in the group of omnivores. The authors
speculate that this higher observed incidence of cervical cancer might
be related to non-dietary factors, for example differences between
groups in attendance for cervical cancer screening. They did not find a
significant difference between dietary groups in relation to the
incidence of colorectal cancer, which contrasts with a study that
aggregated EPIC data from 10 European countries, which found that high
consumption of red and processed flesh was associated with a higher risk
of colorectal cancer (Gonzalez and Riboli 2006, 229). Similarly, an
expert systematic review in the USA deemed that the evidence of the
increased risk for colorectal cancer associated with consuming red and
processed flesh was convincing (WCRF/AICR 2007, 116, 382). The same
review judged that there was limited evidence for a positive association
between the consumption of red and/or processed flesh and increased
risks of cancers of the oesophagus, stomach, pancreas, lung,
endometrium, and prostate (WCRF/AICR 2007, 116). Another expert review
adds breast, bladder, and oral cancer (Anand et al. 2008).
The
link between the consumption of animal products and cancer has also been
studied by Ganmaa and Sato (2005), who correlated the incidence rates
for breast, ovarian, and corpus uteri cancers (using data detailing
cancer incidence between 1993 and 1997) with food intake in 40
countries—even if food consumption was merely estimated by means of
1961–97 FAOSTAT data. They found a positive link between the consumption
of animal products and these hormone-dependent cancers, a finding that
is corroborated by other studies (Larsson et al. 2006). Ganmaa and Sato
(2005) express particular concern with the consumption of milk from
pregnant cows. As many cows in the dairy industry are almost
continuously pregnant, their milk expresses high levels of oestrogen and
progesterone (hormones which are known to stimulate the mammary gland),
which are hypothesised to increase the risks associated with these
cancers (Ganmaa and Sato 2005).
In many situations, men may not
benefit from the consumption of dairy products either. A World Cancer
Research Fund (WCRF) and American Institute for Cancer Research (AICR)
joint expert review concluded that ‘there is limited evidence suggesting
that high consumption of milk and dairy products is a cause of prostate
cancer’, but also that cows’ ‘milk probably protects against colorectal
cancer’ (WCRF/AICR 2007, 129). This is more or less the opposite of
what was found in a longitudinal study of 4,383 English and Scottish
children who participated in a family food study between 1937 and 1939:
no positive link between high cows’ milk consumption and prostate cancer
risk was found, but the study did find a near-tripling in the odds of
colorectal cancer amongst those who had been raised in households with
high dairy consumption (van der Pols et al. 2007). Some other studies,
however, also found a positive link between high consumption of dairy
and prostate cancer risk (N. Allen et al. 2008; Chan et al. 2005;
Torfadottir et al. 2011). Much has been written on the latter issue, but
little clarity has been provided because of the high likelihood of
confounding factors. An analysis of pooled data from 45 observational
studies, supported by a grant from National Dairy Council (Rosemont,
Illinois), found no increased risk (Huncharek et al. 2008).
Apart
from the fact that no dairy products are consumed, many other reasons
have been provided in support of the view that vegan diets are
cancer-protective. One is the fact that vegans are less likely to be
obese (WCRF/AICR 2007). Expert reviews also indicate that diets that are
high in fruits and vegetables are associated with decreased cancer risk
because of the higher levels of health-promoting substances (such as
ascorbic acid, carotenoids, and flavonoids) and a lower level of some
carcinogenic components that have been found in some animal products,
such as dioxins (WCRF/AICR 2007; Craig 2009; Dewell et al. 2008; ADA
2009).
A significant concern with many studies that explore
relative cancer risks of different populations is that they fail to
distinguish between vegetarians and vegans. Consequently, relatively
little is known as yet about the benefits or disadvantages of vegan
diets. The vegetarian group in the study that combined data from the
Oxford Vegetarian Study and the EPIC-Oxford cohort, for example,
included both vegetarians and vegans, resulting in a failure to identify
the relative cancer risk of the latter (Key et al. 2009a). To alert the
reader to this issue, the authors write that to explore the hypothesis
that the consumption of dairy products may increase prostate cancer risk
‘we would need to examine the cancer rates among vegans’, but they are
not consistent in their failure to separate vegans from vegetarians as
they add that ‘there are currently too few cancers [amongst vegans in
their study] to be informative’ (Key et al. 2009a, 195); what they may
have meant to say is that there were too few vegans in the study to
allow for generalisations to be made about vegan diets. As stated in the
paper, however, the claim is informative. In spite of the fact that
generalisations from studies of small populations are inappropriate, the
fact that very few cancers were identified amongst vegans must be
considered to be good news. In 2014, the Oxford team did report findings
separately for the 2,246 vegans who were part of a sub-cohort of 61,647
British people who were followed up for almost 15 years (Key et al.
2014). During this time, there were 4,998 incidents of cancer, and the
incidence was 19% lower in the vegan group than in the omnivorous group.
Another study that has looked at vegans as a separate group is the
AHS-2 study, which has reported a 16% reduction of risk amongst vegan
Adventists compared to omnivorous Adventists (Orlich et al. 2013).
Overall,
it is safe to conclude that many vegan diets are associated with a
lower incidence of cancer than many other diets, even if the jury is
still out on what the ideal diet might be to protect against cancer
(Norris and Messina 2011, 176–178).
Diverticular disease
Diverticular
disease includes two diseases of the colon (large intestine or large
bowel): diverticulosis (the presence of pockets or pouches) and
diverticulitis (infected or inflamed pockets or pouches). A study
published in 1979 explored the incidence of diverticular disease in two
groups of southern English people who did not experience any symptoms of
the disease: 56 vegetarians were compared with 264 non-vegetarian
volunteers. When radiographs of the participants’ colons were analysed
by a consultant radiologist who knew neither the participants nor their
diets, 12% of the former group and 33% of the latter group were
diagnosed to suffer from diverticular disease (Gear et al. 1979). In the
Oxford-EPIC cohort, a sub-cohort of 15,459 participants, combining
vegetarians and vegans, was found to have a 30% reduced risk of
diverticular disease compared with the sub-cohort of 31,574 omnivores
(Crowe et al. 2011). When the vegan participants were isolated from the
vegetarians, the researchers found a 72% lower risk for the former
compared to the omnivores in the study. While these findings have
primarily been associated with the fact that vegetarians and vegans tend
to consume more fibre, different studies (with, arguably, participants
less health-conscious than participants in the Oxford-EPIC studies)
found that, after adjusting for differences in dietary fibre between
study participants, high consumption of total fat or of red flesh
(Aldoori et al. 1994), the consumption of flesh from sheep and cows as
well as milk products (Manousos et al. 1985), and the ‘long-term and
frequent’ consumption of flesh (Lin et al. 2000) were linked with
diverticular disease. Whereas only the Aldoori et al. (1994) study was a
prospective cohort study—the ones by Manousos et al. (1985) and by Lin
et al. (2000) being small case-control studies—these findings lend
strong support for the view that vegan diets that tend to be high in
fibre are much less likely to cause diverticular disease than many
omnivorous diets.
Parkinson’s disease
On the basis of
population-based studies, McCarty (2001b) found that Parkinson’s disease
was less prevalent in sub-Saharan Africa, rural China, and Japan. A
similar observation was made by de Lau and Breteler (2006), who report
that the incidence of Parkinson’s is lower in East Asian populations,
including Chinese, Taiwanese, and Japanese populations, than in Western
populations. McCarty (2001b) also reported that the incidence of
Parkinson’s amongst African Americans was very similar to that of white
Americans, suggesting that the low incidence of Parkinson’s amongst
sub-Saharan Africans may not stem from genetic factors. As sub-Saharan
and East Asian populations consume relatively few animal products,
McCarty (2001b) suggests that vegan diets may be protective and that
they may even be therapeutically beneficial through a number of
mechanisms, including the promotion of vascular health and blood-brain
transport of L-dopa, as well as through caloric restriction, which was
found to protect the central dopaminergic neurons of mice. A different
study, funded by Syngenta Crop Protection, reviewed the epidemiological
literature, as well as the literature on risks and protective factors,
concluding that little is known as yet about the aetiology of
Parkinson’s disease, but that there is some evidence that the
consumption of dairy products increases risk (Wirdefeldt et al. 2011). A
very small Indian study, however, did not find a reduction in
Parkinson’s for those who adopted a vegetarian diet (Behari et al.
2001). In his review of the literature, Giovanni (2009, 326) comments
that ‘data regarding the prevalence of Parkinson’s disease in vegetarian
or vegan groups or relative clinical findings are not available as
yet’. Accordingly, the view that a vegan diet might be protective of
Parkinson’s is no more than an interesting hypothesis at the present
time.
Insulin-like growth factor 1 (IGF-1) and mTORC1 related diseases
Insulin-like
growth factor 1 (IGF-1) is a growth-stimulating hormone that is found
in the human body. ‘mTORC1’ refers to mammalian target of rapamycin
complex 1, a nutrient-sensitive enzyme that responds to a range of
signals in the human body, including IGF-1.
Overproduction of
IGF-1 has been associated with many diseases (Hoppe et al. 2006). IGF-1
is a key factor involved with episodes of rapid growth during childhood;
the growth acceleration hypothesis claims that IGF-1 contributes to the
development of a range of diseases that may not manifest themselves
until much later in life (Singhal and Lucas 2004). Diets that increase
IGF-1 levels in the blood have also been associated with some cancers,
including colorectal and breast cancer (O’Neill 2010, 200).
Studies
that compared vegan with other study participants have found that
vegans had lower levels of IGF-1 (Fontana et al. 2006; N. Allen et al.
2002). Two cross-sectional analyses of the EPIC-study found that the
production of IGF-1 was particularly stimulated by the consumption of
dairy products (Norat et al. 2007; Crowe et al. 2009). The same
conclusion was reached in a much larger study that combined findings
from 15 cross-sectional studies and 8 randomised controlled trials (Qin
et al. 2009). Dairy products have come under increased scrutiny not only
because of their role in IGF-1 stimulation, but also because they, as
well as animals’ flesh, contain large quantities of calories and
leucine. Together with products that have a high glycaemic load
(including hyperglycaemic carbohydrates), products that are high in
calories and leucine and that stimulate IGF-1 are thought to play a
major, synergistic role in the activation of mTORC1 (Melnik 2012). This
has been held to cause or worsen acne, a skin disease that prevails
amongst more than 85% of teenagers in Western countries, and that is
absent amongst people who eat palaeolithic diets, such as the
inhabitants of Kitava, one of the Trobriand Islands of Papua New Guinea
(Melnik 2012, 20–21; Lindeberg et al. 1999). Increased mTORC1-signalling
has also been linked with a number of other Western health concerns,
including obesity and type 2 diabetes (Shaw and Cantley 2006; Zoncu et
al. 2011). Men who suffer from severe, long-lasting acne have also been
found to have an increased risk of developing prostate cancer later in
life (Sutcliffe et al. 2007). Laboratory experiments, including
experiments with mice, have suggested that this may stem from the
possibility that long-term hyperstimulation of mTORC1-signalling
promotes the development of cancer tumours (Nardella et al. 2009; Wang
et al. 2011).
Critical scrutiny of the Kitavans’ diet around 1990
reveals that they ate a diet that contained mainly tubers that provide
carbohydrates with a low glycaemic index (such as yam, sweet potato,
taro, and manioc), as well as fruits, vegetables, coconuts, and fish
(Lindeberg et al. 1999, 1216). In a randomised controlled trial with
patients who suffered from ischaemic heart disease combined with either
glucose intolerance or type 2 diabetes, such a diet has also been shown
to improve glucose tolerance more than a Mediterranean-style diet that
included whole grains and low-fat dairy products (Lindeberg et al.
2007). Compared to a Swedish control group, it was also found that
Kitavans consumed a much smaller amount of mono-unsaturated fats and a
higher amount of n-3 fatty acids (Lindeberg et al. 1999). In light of
these studies and the connection between mTORC-1 and a range of Western
diseases that are rare or absent amongst Kitavans, the adoption of a
vegan diet that is similar to the palaeolithic diet that was adopted by
the Kitavans around 1990 has been recommended (Melnik 2012). One reason
why such a diet is low in foods with a high glycaemic index is that it
contains little fructose—which is present in many processed foods
through the widespread use of high fructose corn syrup (Melnik 2012, 29;
McCarty 2011; Seneff et al. 2011).
A vegan diet that is similar
to the traditional Kitavan diet may also protect against a number of
ageing-associated diseases, including Alzheimer’s disease (Seneff et al.
2011; McCarty 2001a; McCarty 2003c). Alzheimer’s disease patients have
been shown to have elevated levels of IGF-1 (Melnik 2011). This may help
to explain why, when 2,148 New Yorkers without a diagnosis of dementia
who were at least 65 were followed up over a period of nearly four
years, it was found that the incidence of Alzheimer’s was greater
amongst those who ate the largest quantity of animal products (Gu et al.
2010).
Other benefits and concerns
A further benefit for
young children is that a vegan diet avoids the consumption of cows’
milk, which not only is low in iron, but also causes occult intestinal
blood loss in about 40% of children below the age of one, and which
contains high quantities of calcium as well as casein and other proteins
that all inhibit the absorption of dietary non-haem iron (Ziegler 2011,
38S–40S). Casein has also been found to inhibit the absorption of zinc
(Lönnerdal 2000). These concerns may help to explain why nutritionists
do not recommend the consumption of cows’ milk for children below the
age of one (Millward and Garnett 2010, 104). Middle ear infection
(otitis media) has also been found to be more severe and more common
amongst children with cows’ milk allergies (Juntti et al. 1999). Such
allergies are by no means restricted to children as many people are
lactose intolerant, lacking sufficient quantities of the lactase enzyme
within the lining of the small intestine to allow the body to abs
absorb
lactose, whilst some people are also allergic to other components in
dairy products (Millward and Garnett 2010, 104–105). In light of their
hypothesis that the continued production of lactase throughout adulthood
may only have developed in northern Europeans about a thousand years
ago, Norris and Messina (2011, 43) argue that the concept of ‘lactose
intolerance’ stems from a Western bias as good lactose tolerance may be
the exception, rather than the rule.
Limited evidence has been
presented to support the view that vegan diets may also reduce the risk
of cataracts, dementia, gallstones, kidney disease, and rheumatoid
arthritis (B. Davis and Melina 2014, 72–80). As many toxic substances
accumulate inside the bodies of animals, vegan diets also tend to have
lower levels of many toxic substances, including
biodegradation-resistant organic environmental pollutants, such as
polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans
(PCDFs), and polychlorinated biphenyls (PCBs), as well as of toxic
heavy metals, such as mercury (Schecter et al. 1997; O’Neill 2010, 201).
In
spite of these benefits, recent research that included a sample of 422
vegans from the Oxford-EPIC cohort revealed that vegans had relatively
high circulating concentrations of uric acid, which may contribute to
the development of gout, chronic kidney disease, cardio-vascular
disease, and cancer; these high concentrations of uric acid are
attributed to the exclusion of dairy products and to low calcium
consumption (J. Schmidt et al. 2013). The authors are cautious, however,
about the possible existence of causal connections between uric acid
and these diseases, and they add that concentrations can be lowered
through increased calcium consumption.
An additional concern for
people with small stomach capacities, such as small children, is that
vegan diets can be bulky due to increased consumption of dietary fibre,
which can cause early satiety. Accordingly, McEvoy and Woodside (2010,
86–87) advise that vegan children take frequent meals and snacks, and
that foods that are high in fat, such as nuts and nut butters, be used
to provide sufficient calories and protein. For those who suffer from
nut allergies, however, adequate substitutes must be used.
4. Conclusion
After
a brief introduction, I argued in the second part of this appendix that
vegan diets can be nutritionally adequate, but that vegans must make
sure to consume foods that contain adequate amounts of vitamin B12 and
omega-3 fatty acids as the former cannot be obtained from plants and the
latter are present in significant quantities only in a few common vegan
foods. The former can be obtained by consuming products that contain
the B12 vitamin. Adequate consumption of the latter is facilitated by
the consumption of plants and plant foods that have relatively high
levels of omega-3, such as chia, flax, canola (rapeseed), hemp, walnuts,
perilla, olive oil, blackcurrant seed oil, and plants in the Echium
genus, as well as by the consumption of brown algae (kelp) oils. People
with specific dietary requirements, such as young and old people, must
make sure that they eat sufficient foods that are relatively rich in
calories and relatively easy to digest, such as cooked foods.
The
question whether vegan diets might be healthier than other diets was
addressed in the third part. The evidence to support the possibility
that vegan diets might be healthier is limited. Factors that complicate
the development of our understanding include the facts that relatively
few people adopt vegan diets, that some people’s adoption of vegan diets
may be triggered by psychological illness, and that many are biased
against vegan diets. In spite of these limitations, there is sufficient
evidence to conclude that many diets that are high in fruits and
vegetables are associated with many health benefits, including
reductions in cardio-vascular disease and some types of cancer.
Whereas
this appendix has discussed scientific evidence for and against vegan
diets, it has not answered the question of what a good vegan diet is, at
least not in detail. For those who seek more practical advice on what
kind of vegan diet to adopt to meet nutritional requirements, I
recommend the books Becoming Vegan (B. Davis and Melina 2014) and,
particularly, Vegan for Life (Norris and Messina 2011).
Publication Details
Copyright
Text © Jan Deckers 2016.
This
work is licensed under the Creative Commons Attribution 4.0
International License. To view a copy of this license, visit
http://creativecommons. org/licenses/by/4.0/ or send a letter to
Creative Commons, 444 Castro Street, Suite 900, Mountain View,
California, 94041, USA. This license allows for copying any part of the
work for personal and commercial use, providing author attribution is
clearly stated.
Publisher
Ubiquity Press, London
NLM Citation
Deckers
J. Animal (De)liberation: Should the Consumption of Animal Products Be
Banned? London: Ubiquity Press; 2016. Might a Vegan Diet Be Healthy, or
Even Healthier?
free online download all
individual and International organisations encouraging humans to search
for food just like birds, animals etc., to overcome hunger the worst
illness with pictures and videos
REGISTRATION OF COOPERATIVES (source: Cooperative …
Search domain
How to Apply for Grants | GRANTS.GOV
Search domain
CIPC :: Registering your Co-operative
Search domain
Register your Co-operative A very simple definition of a co-operative would be to say it is a business where a group of people get together voluntary to address their common needs. A co-operative is a distinct form of enterprise that provides services and/or products to its members.
What Is A Cooperative? And How Do You Start One?
Search domain
How to Start an Association Step by Step
Search domain
How to Start a Farm, Your Complete Guide to Success
Search domain
PDF monitoring and evaluation (M&E) guide - IFRC
Search domain
How to Write a Small Farm Business Plan - Treehugger
Search domain
(PDF) CO-OPERATIVE ACCOUNTING | Dr. Moses Gweyi - Academia.edu
Search domain
1. The society records a cheque of sh. 4,000 being rental income on properly leased out 2. The society earned interest on fixed deposit account with Co-operative Bank of sh. 3,000 pO P r o v i d i n g Q u a l i t y C o -o p e r a t i v e A c c o u n t i n g Page 43 3.
AARP® Official Site - Join & Explore the Benefits
Search domain
free online step by step guide to register an International multi purpose vegan farmers cooperative society
Image
Web results
Step by step guide to setting up a co-operative society - iPleaders
05-Sep-2017 — The laws governing the societies are “THE co-operative … The objectives of commercial organization and … Step 4: Application has to be made to the Registration …
Missing: free vegan
Image
How to Register Co-operative Society | Step by Step Guide
Members of Co-operative Societies. Co- operative society of which all the members are individuals, by at least fifty persons from each of the states …
Missing: online vegan farmers
Image
Society Registration in India - Online Procedure & Documents Required
19-Mar-2021 — A Society Registration is an association of several individuals combined using a … Start your free trial now! … This act was implemented with the purpose of augmenting the legal …
Missing: vegan farmers
Image
06-Sep-2019 — Since its formal launch in 1904 in India, the Indian Cooperative Movement has played very important role in the Indian economy …
Missing: free step vegan
Image
Prohibition against the use of the word “Co- operative”. 113. Address of a co-operative society. 114. Copy of Act, rules and bye-laws to be open to …
150 pages·1 MB
Image
Primary Agricultural Cooperative Society Registration Criteria (Checklist) … society is free from the said law … (vi) Farming Societies … Login to this website as per the instructions on the screen.
25 pages·3 MB
Image
FAQs on Enforcement. Compliance Imports Standards NCCP Codex Regulation Licensing / Registration. Q 1. What is enforcement of FSS Act , …
The Global Warming Issue
Backpacker · Vol. 35, No. 252 · Magazine
The revolutionary new 3-step system that supports optimal performance by … Marmot JETBOIL Shop online at basspro.com For a FREE catalog … USE COMMON SENSE AS YOUR GUIDE …
Image
Los Angeles Magazine · Vol. 48, No. 11 · Magazine
Down a flight of stone steps, the cavelike GONZALES candles (E14 Olvera St., … A planned. community might be for you. We build … He compiled these into a bound manual and three notebooks.
Image
Backpacker · Vol. 28, No. 184 · Magazine
to the use of their names and/or likenesses for advertising and publicity … MEADE4 Call 1-800 - 62- MEADE for a free copy of Meade Telescope … Latest step in the IntegraFitTM revolution.
FARMER PRODUCER ORGANISATIONS - NABARD
Producer Organisation Registered as Cooperative Society. 15 … The Objective of this Manual is to act as a guide to Producer Organisation … submission online by the authorized person of the