A variety of vegan foods

Vegan nutrition refers to the unique set of advantages and challenges that are part of vegan diets. The American Dietetic Association and Dietitians of Canada regard the vegan diet as appropriate for all stages of the life-cycle and as offering protection against cardiovascular disease, cancer, and other diseases. They caution that poorly planned vegan diets can be deficient in vitamin B₁₂, vitamin D, calcium, iodine, iron and omega-3 fatty acids.^[1] Just as with omnivorous and vegetarian diets, ensuring a balanced diet is key.

Background[edit]

Brendan Brazier, vegan triathlete.

Doctors Dean Ornish, T. Colin Campbell, John A. McDougall, Michael Klaper, Caldwell Esselstyn, Michael Greger, Joel Fuhrman, and Neal D. Barnard claim that high animal fat and protein diets, such as the standard American diet, are detrimental to health.^[2][3][4] They also state that a lifestyle change incorporating a vegan whole foods diet could not only prevent various degenerative diseases, such as coronary artery disease, but reverse them.^{[5][6][7][8][9]} A number of documentary films, such as Fat, Sick and Nearly Dead, Planeat and Forks over Knives, focus on the purported health benefits of plant-based diets. Although there is general consensus amongst doctors advocating plant-based diets, Joel Fuhrman and Michael Greger have disagreed with Campbell and Esselstyn on the use of nuts and seeds.^[10]

Some top athletes, such as Brendan Brazier, follow a vegan diet, including raw veganism.^[11] Vegan diets tend to be higher in dietary fibre, magnesium, folic acid, vitamin C, vitamin E, iron, and phytochemicals, and lower in calories, saturated fat, cholesterol, long-chain omega-3 fatty acids, vitamin D, calcium, zinc, and vitamin B12.^[12] Because uncontaminated plant foods do not provide vitamin B12 (which is produced by microorganisms such as bacteria), researchers agree that vegans should eat foods fortified with B12 or take a daily supplement.^[13]

Nutrition[edit]

Poorly planned vegan diets may be low in vitamin B₁₂, omega-3 fatty acids, vitamin D, calcium, iron and iodine. Nonetheless, well-balanced vegan diets can meet all these nutrient requirements and are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence.^[14]

Vitamin B₁₂[edit]

This vegan food pyramid is based on suggestions from the American Dietetic Association

Vitamin B₁₂ deficiency is potentially extremely serious, leading to megaloblastic anemia, nerve degeneration and irreversible neurological damage.

Evidence suggests that vegans who are not taking vitamin B₁₂ supplements do not consume sufficient servings of B₁₂ and often have abnormally low blood concentrations of vitamin B₁₂.^[15][16] This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B₁₂.

The Vegan Society and Vegan Outreach recommend that vegans eat foods fortified with B12 or take a supplement.^[17]

Protein[edit]

Proteins are composed of amino acids, and a common though unfounded concern with protein acquired from vegetable sources is an adequate intake of the essential amino acids, which cannot be synthesised by the human body. While dairy and egg products provide complete protein sources for ovo-lacto vegetarians, the only vegetable sources with significant amounts of all eight types of essential amino acids are lupin beans, soy,^[18] hempseed, chia seed,^[19] amaranth,^[20] buckwheat,^[21] and quinoa.^[22] However, the essential amino acids can also easily be obtained by eating a variety of complementary plant sources that, in combination, provide all eight essential amino acids (e.g. brown rice and beans, or hummus and whole wheat pita, though protein combining in the same meal is not necessary). A 1994 study found a varied intake of such sources can be adequate.^[23]

Omega-3 fatty acids[edit]

Flax seed is a rich source of ALA, the precursor to DHA and EPA, the omega-3 fatty acids the FDA considers to be healthful.

Vegan diets can be low in omega-3 fatty acids (O3FA). Major vegan sources of O3FA include algae, hempseeds and hempseed oil, walnuts, flaxseeds and flaxseed oil, olive oil, canola (rapeseed) oil, avocado and chia seeds. However, diets lacking generous amounts of sea vegetables (seaweed) generally lack a direct source of long-chain O3FA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).^{[citation needed]} Vegan diets, like the standard American diet, may also have a high ratio of O6FA to O3FA, which inhibits the conversion of short-chain fatty acids such as alpha-Linolenic acid (ALA), found in most vegan O3FA sources, to EPA and DHA.^[1] Short-term supplemental ALA has been shown to increase EPA levels but not DHA levels, suggesting poor conversion of the intermediary EPA to DHA.^[24] DHA supplements derived from DHA-rich microalgae are available,^[1] and the human body can also convert DHA to EPA.^[25]

Walnuts are a source of omega-3 fatty acids

While there is no scientific consensus on the role of omega-3 fatty acids, they may reduce the risk of coronary heart disease,^[1] lower triglycerides, stabilize mood and help prevent depression, help reduce symptoms of ADD, reduce joint pain and other rheumatoid problems, and reduce the risk of dementia in older age.^{[citation needed]} While there is little evidence of adverse health or cognitive effects due to DHA deficiency in adult vegetarians or vegans, fetal and breast milk levels remain a concern.^[24] EPA and DHA supplementation has been shown to reduce platelet aggregation in vegetarians, but a direct link to cardiovascular morbidity and mortality, which is already lower for vegetarians, has yet to be determined.^[26]

Vitamin D[edit]

The human body can synthesize vitamin D when skin is exposed to ultraviolet radiation from the sun. If vegans cannot obtain enough vitamin D from exposure to sunlight, it is recommended that they eat foods or pills fortified with synthetic vitamin D2 (vitamin D3 supplements are animal-derived, mainly from lanolin). Those who don't expose their extremities for at least 15–30 minutes per day or those living at latitudes close to the poles) are vulnerable to vitamin D deficiencies.

Vitamin D acts as a hormone, sending a message to the intestines to increase the absorption of calcium and phosphorus, which produces strong bones. Vitamin D also works in concert with a number of other vitamins, minerals, and hormones to promote bone mineralization. Research also suggests that vitamin D may help maintain a healthy immune system and help regulate cell growth and differentiation.

Calcium[edit]

It is recommended that vegans eat three servings per day of a high-calcium food, such as fortified soy milk, almonds, hazelnuts, kale, collard greens, Chinese greens, and take a calcium supplement or other calcium-fortified foods as necessary.^[1]

Many studies have examined possible correlation between veganism, calcium intake and bone health. The EPIC-Oxford study suggested that vegans who consumed 525mg or less of calcium per day have an increased risk of bone fractures over meat eaters and vegetarians, but that vegans consuming more than 525 mg/day had a risk of fractures similar to other groups. Overall, the entire group of vegans had a higher risk of fractures.^[27] A 2009 study of bone density found the bone density of vegans was 94 percent that of omnivores, but deemed the difference clinically insignificant.^[28] Another study in 2009 by the same researchers examined over 100 vegan post-menopausal women, and found that their diet had no adverse effect on bone mineral density (BMD) and no alteration in body composition.^[29] Biochemist T. Colin Campbell suggested in The China Study (2005) that osteoporosis is linked to the consumption of animal protein because, unlike plant protein, animal protein increases the acidity of blood and tissues, which is then neutralized by calcium pulled from the bones resulting in hypercalciuria. Cornell wrote that his China-Oxford-Cornell study of nutrition in the 1970s and 1980s found that, in rural China, "where the animal to plant ratio [for protein] was about 10 percent, the fracture rate is only one-fifth that of the U.S."^[30]

Calcium is one component of the most common type of human kidney stones, calcium oxalate. Some studies suggest that people who take supplemental calcium have a higher risk of developing kidney stones, and these findings have been used as the basis for setting the recommended daily intake (RDI) for calcium in adults.^[31][32][33]

Iodine[edit]

One study reported a "potential danger of iodine deficiency disorders due to strict forms of vegetarian nutrition, especially when fruits and vegetables grown in soils with low [iodine] levels are ingested."^[34] Iodine, however, is usually supplied by iodized salt and other sources in first world countries. Other significant sources of iodine include sea vegetables (seaweed) and bread made with dough conditioners.^{[citation needed]}

However, Raw Vegans who eat a high fruit diet and abstain from eating overt salt, can find enough iodine in foods such as bananas, permitting that caloric needs are met.^{[citation needed]}

Iron[edit]

It is recommended for vegans to eat iron-rich foods and vitamin C daily.^[35] In several studies, vegans were not found to suffer from iron-deficiency any more than non-vegans.^{[36][37][38][39]}

Choline[edit]

It is recommended for vegans to eat food rich in choline, as plant based sources of choline are limited.^[40] Soy lecithin, cauliflower, spinach, wheat germ, firm tofu, kidney beans, quinoa and amaranth are vegan sources of choline. The Adequate Intake (AI) of choline is 425 mg (milligrams) per day for adult women; higher for pregnant and breastfeeding women. The AI for adult men is 550 mg/day.^[41]

See also[edit]

• Nutritional medicine
• Raw veganism
• The China Study
• Vegetarian nutrition

Documentaries[edit]

1990s[edit]

• Diet for a New America (1991) by John Robbins; featuring Michael Klaper, T. Colin Campbell and John A. McDougall
• A Diet for All Reasons (1993) by Michael Klaper

2000s[edit]

• Eating (2002) by Mike Anderson; featuring Caldwell Esselstyn and John A. McDougall
• Total Health Solution (2003) by John A. McDougall
• Simply Raw: Reversing Diabetes in 30 Days (2009) by Gabriel Cousens; featuring Joel Fuhrman

2010s[edit]

• Latest in Clinical Nutrition (2010) by Michael Greger
• Fat, Sick and Nearly Dead (2010) by Joe Cross; featuring Joel Fuhrman
• Planeat (2010) by Shelley Lee Davies and Or Shlomi; featuring T. Colin Campbell and Caldwell Esselstyn
• Forks over Knives (2011) by Lee Fulkerson; featuring T. Colin Campbell, Caldwell Esselstyn and Neal D. Barnard
• Vegucated (2011) by Marisa Miller Wolfson; featuring T. Colin Campbell and Joel Fuhrman

Further reading[edit]

This article lacks ISBNs for the books listed in it. Please make it easier to conduct research by listing ISBNs. If the {{Cite book}} or {{citation}} templates are in use, you may add ISBNs automatically, or discuss this issue on the talk page. (June 2012)

1980s[edit]

• John Robbins (1987) Diet for a New America
• Michael Klaper (1987) Vegan Nutrition

1990s[edit]

• Dean Ornish (1996) Dr. Dean Ornish's Programme for Reversing Heart Disease
• John A. McDougall (1996) The McDougall Program for a Healthy Heart

2000s[edit]

• Physicians Committee for Responsible Medicine (2002) Healthy Eating for Life to Prevent and Treat Cancer
• Joel Fuhrman (2003) Eat to Live
• T. Colin Campbell (2005) The China Study
• Michael Greger (2005) Carbophobia!
• Will Tuttle (2005) World Peace Diet
• Neal D. Barnard (2007) Dr. Neal Barnard's Program for Reversing Diabetes
• Caldwell Esselstyn (2008) Prevent and Reverse Heart Disease
• Barnard, Neal D; Cohen, Joshua; Jenkins, David JA; Turner-Mcgrievy, Gabrielle; Gloede, Lise; Green, Amber; Ferdowsian, Hope (2009). "A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: A randomized, controlled, 74-wk clinical trial". American Journal of Clinical Nutrition 89 (5): 1588S–1596S. doi:10.3945/ajcn.2009.26736H. PMC 2677007. PMID 19339401. 
• Jacobs, David R; Gross, Myron D; Tapsell, Linda C (2009). "Food synergy: An operational concept for understanding nutrition". American Journal of Clinical Nutrition 89 (5): 1543S–1548S. doi:10.3945/ajcn.2009.26736B. PMC 2731586. PMID 19279083. 
• Fraser, Gary E (2009). "Vegetarian diets: What do we know of their effects on common chronic diseases?". American Journal of Clinical Nutrition 89 (5): 1607S–1612S. doi:10.3945/ajcn.2009.26736K. PMC 2677008. PMID 19321569. 

References[edit]

External links[edit]

• Nutritional guidelines by the Vegan Society
• Shattering The Meat Myth: Humans Are Natural Vegetarians by Kathy Freston, The Huffington Post, June 11, 2009