Vegan nutrition

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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, though they caution that poorly planned vegan diets can be deficient in vitamin B12, vitamin D, calcium, iodine, iron and omega-3 fatty acids.[1]

Contents

[edit] Benefits of a vegan diet

Doctors Dean Ornish, T. Colin Campbell, John A. McDougall, Caldwell Esselstyn 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 low fat vegan diet could not only prevent various degenerative diseases, such as coronary artery disease, but reverse them.[5][6][7][8][9]

[edit] Nutrition

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

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.

[edit] Vitamin B12

Further information: Vitamin B12 deficiency

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.[10] This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B12.

However recent studies (such as the Framingham study) have shown that many omnivores are also deficient in vitamin B12—in fact around 40% of Americans. This is attributed to various things, including the inability to produce the intrinsic factor which is required to successfully metabolize B12.

[edit] Omega-3 fatty acids

Flax seed is a rich source of ALA, but contains negligible amounts of 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). Vegan diets 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.[11] DHA supplements derived from DHA-rich microalgae are available,[1] and the human body can also convert DHA to EPA.[12]

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.[11] 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.[13]

[edit] Vitamin D

Further information: Hypovitaminosis D

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.

[edit] Calcium

It is recommended that vegans eat three servings per day of a high-calcium food, such as fortified soy milk, almonds, hazelnuts, and take a calcium supplement as necessary.[1] The EPIC-Oxford study suggested that vegans have an increased risk of bone fractures over meat eaters and vegetarians, likely because of lower dietary calcium intake, but that vegans consuming more than 525 mg/day had a risk of fractures similar to other groups.[14] A 2009 study of bone density found the bone density of vegans was 94 percent that of omnivores, but deemed the difference clinically insignificant.[15] 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.[16] 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."[17] 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. [18] [19] [20]

[edit] Iodine

Further information: Iodine deficiency

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."[21] 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.

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.

[edit] Iron

It is recommended for vegans to eat iron-rich foods and vitamin C daily.[22] In several studies, vegans were not found to suffer from iron-deficiency any more than non-vegans.[23]

[edit] Choline

It is recommended for vegans to eat food rich in choline, as plant based sources of choline are limited[24]. 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.[25]

[edit] See also

[edit] References

  1. ^ a b c d e For an overview, see "Position of the American Dietetic Association and Dietitians of Canada: vegetarian diets", Canadian Journal of Dietetic Practice and Research. Summer 2003, 64(2):62-81; also available here, accessed January 31, 2011.
    • For vitamin B12, Norris, Jack. "Vitamin B12: Are you getting it?", Vegan Outreach, July 26, 2006, accessed February 4, 2011: "B12 is generally found in all animal foods (except honey). Contrary to rumors, there are no reliable, unfortified plant sources of vitamin B12, including tempeh, seaweeds, and organic produce. The overwhelming consensus in the mainstream nutrition community, as well as among vegan health professionals, is that plant foods do not provide vitamin B12, and fortified foods or supplements are necessary for the optimal health of vegans, and even vegetarians in many cases. Luckily, vitamin B12 is made by bacterial fermentation such that it does not need to be obtained from animal products."
    • For vitamin D, see "Bones, Vitamin D, and Calcium", Vegan Outreach, January 9, 2007, accessed February 4, 2011: "If you get exposed to the following amounts of midday sun (10 am to 2 pm), without sunscreen, on a day when sunburn is possible (i.e., not winter or cloudy), then you do not need any dietary vitamin D that day." On other days, take a supplement; see page for recommendations.
    • For calcium, see "Bones, Vitamin D, and Calcium", Vegan Outreach, January 9, 2007, accessed February 4, 2011: "Based on research showing that vegans who consumed less than 525 mg per day of calcium had higher bone fracture rates than people who consumed more than 525 mg per day (14), vegans should make sure they get a minimum of 525 mg of calcium per day. It would be best to get 700 mg per day for adults, and at least 1,000 mg for people age 13 to 18 when bones are developing. This can most easily be satisfied for most vegans by eating high-calcium greens on a daily basis and drinking a nondairy milk that is fortified with calcium."
    • For vitamin D and calcium, also see Appleby, P. et al. "Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford", European Journal of Clinical Nutrition, volume 61, issue 12, February 2007. doi:10.1038/sj.ejcn.1602659
    • For iodine, see "Iodine", Vegan Outreach, December 26, 2006, accessed February 4, 2011: "Iodine is needed for healthy thyroid function which regulates metabolism. Both too much, and too little iodine can result in abnormal thyroid metabolism. ... Studies have shown that vegans in Europe (where salt is either not iodized or not iodized at high enough levels) who do not supplement (as well as those who oversupplement) have indications of abnormal thyroid function."
    • For iron, "Iron deficiency—adults", Better Health Channel, Government of Victoria, Australia, accessed February 4, 2011: "High-risk groups such as vegetarians, adolescent girls and women athletes need to eat iron-rich foods each day (combined with foods that are high in vitamin C). ... Vegetarians who exclude all animal products from their diet may need almost twice as much dietary iron each day as non-vegetarians. Sources include dark green leafy vegetables—such as spinach—and raisins, nuts, seeds, beans, peas, and iron-fortified cereals, breads and pastas."
    • For omega-3 fatty acids, see "Omega-3 Fatty Acid Recommendations for Vegetarians", Vegan Outreach, accessed February 4 2011: "Without diet planning, vegans and vegetarians have low omega-3 intakes and blood levels; and in some cases, elderly vegans have close to none." Vegans should therefore take supplements; use low omega-6 oils like olive, avocado, peanut, or canola; and consume 0.5 g of uncooked alpha-linolenic acid (ALA) daily (e.g. 1/4 teaspoon of flaxseed oil). See page for details.
  2. ^ Segelken, Roger (2001-06-28). "China Study II: Switch to Western diet may bring Western-type diseases". Cornell Chronicle. http://www.news.cornell.edu/Chronicle/01/6.28.01/China_Study_II.html. Retrieved 2006-09-15. 
  3. ^ "China-Cornell-Oxford Project On Nutrition, Environment and Health at Cornell University". Division of Nutritional Sciences. Cornell University. http://www.nutrition.cornell.edu/ChinaProject/. Retrieved 2006-09-15. 
  4. ^ Barnard, Neal D. (2007). Dr. Neal Barnard's Program for Reversing Diabetes. New York: Rodale. pp. 40–50. "Set aside animal products" 
  5. ^ Ornish D, Brown SE, Scherwitz LW, et al. (July 1990). "Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial". Lancet 336 (8708): 129–33. doi:10.1016/0140-6736(90)91656-U. PMID 1973470. 
  6. ^ Campbell TC, et al. (Oct 2002). "Medically supervised water-only fasting in the treatment of borderline hypertension". J Altern Complement Med. 8 (5): 643–50. doi:10.1089/107555302320825165. PMID 12470446. 
  7. ^ McDougall J, et al. (Feb 2002). "Effects of a very low-fat, vegan diet in subjects with rheumatoid arthritis". J Altern Complement Med. 8 (1): 71–5. doi:10.1089/107555302753507195. PMID 11890437. 
  8. ^ Esselstyn CB Jr. (Aug 1999). "Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology)". Am J Cardiol. 84 (3): 339–41. doi:10.1016/S0002-9149(99)00290-8. PMID 10496449. 
  9. ^ Barnard ND, et al. (Aug 2006). "A low-fat vegan diet improves glycemic control and cardiovascular risk factors in a randomized clinical trial in individuals with type 2 diabetes". Diabetes Care 29 (8): 1777–83. doi:10.2337/dc06-0606. PMID 16873779. 
  10. ^ See, for example, Hokin BD and Butler T: “Cyanocobalamin (vitamin B-12) status in Seventh-day Adventist ministers in Australia” in American Journal of Clinical Nutrition, September 1999, 70:576S-578S; and Krajcovicova-Kudlackova M, Blazicek P, Kopcova J, Bederova A and Babinska K: “Homocysteine Levels in Vegetarians versus Omnivores” in Annals of Nutrition & Metabolism, 2000, 44:135-138; and VeganHealth.org: B12 and Chronic Disease: Homocysteine. Retrieved 26 April 2007.
  11. ^ a b Sanders, Thomas A.B. (August–September 2009). "DHA status of vegetarians". Prostaglandins, Leukotrienes, and Essential Fatty Acids (International Society for the Study of Fatty Acids and Lipids) 81 (2–3): 137–141. doi:10.1016/j.plefa.2009.05.013. ISSN 0952-3278. PMID 19500961. 
  12. ^ http://content.health.msn.com/content/article/91/101125.htm?GT1=5100[dead link]
  13. ^ Mezzano, Diego; Karin Kosiel, Carlos Martínez, Ada Cuevas, Olga Panes, Eduardo Aranda, Pablo Strobel, Druso D. Pérez, Jaime Pereira, Jaime Rozowski and Federico Leighton (1 November 2000). "Cardiovascular Risk Factors in Vegetarians: Normalization of Hyperhomocysteinemia with Vitamin B12 and Reduction of Platelet Aggregation with n-3 Fatty Acids". Thrombosis Research 100 (3): 153–160. doi:10.1016/S0049-3848(00)00313-3. PMID 11108902. 
  14. ^ P Appleby; A Roddam, N Allen and T Key (February 2007). "Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford" (fee required). European Journal of Clinical Nutrition 61 (12): 1400–6. doi:10.1038/sj.ejcn.1602659. PMID 17299475. http://www.nature.com/ejcn/journal/v61/n12/full/1602659a.html. Retrieved 2007-02-25. 
  15. ^ Ho-Pham, L.T., et al. "Effect of vegetarian diets on bone mineral density: a Bayesian meta-analysis", Am J Clin Nut, October 2009, volume 90, issue 4, pp. 943–9hg50.
  16. ^ Ho-Pham. L.T. "Veganism, bone mineral density, and body composition: a study in Buddhist nuns", Osteoporos Int, volume 20, issue 12, December 2009, pp. 2087–2093.
  17. ^ Campbell, T. Colin. The China Study. Benbella Books, 2006, pp. 205–208.
  18. ^ *Brody, Jane E. "Huge Study Of Diet Indicts Fat And Meat", The New York Times, May 8, 1990
  19. ^ *Junshi, Chen; Campbell; T. Colin; Junyao, Li; and Peto, R. (eds). Diet, lifestyle, and mortality in China: a study of the characteristics of 65 Chinese counties. Oxford University Press; Cornell University Press; People's Medical Publishing House, 1990.
  20. ^ *See review: Byers, Tim (Centers for Disease Control). "Diet, lifestyle, and mortality in China: a study of the characteristics of 65 Chinese counties", American Journal of Epidemiology, accessed February 3, 2011.
  21. ^ Thomas Remer, Annette Neubert and Friedrich Manz: “Increased risk of iodine deficiency with vegetarian nutrition”. British Journal of Nutrition, 1999, 81:45-49. Retrieved 4 January 2007.
  22. ^ "Iron deficiency—adults". http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/iron_deficiency_adults?open. "High-risk groups such as vegetarians, adolescent girls and women athletes need to eat iron-rich foods each day (combined with foods that are high in vitamin C). ... Vegetarians who exclude all animal products from their diet may need almost twice as much dietary iron each day as non-vegetarians. Sources include dark green leafy vegetables—such as spinach—and raisins, nuts, seeds, beans, peas, and iron-fortified cereals, breads and pastas" 
  23. ^ see: (1.) [Larsson CL, Johansson GK. Dietary intake and nutritional status of young vegans and omnivores in Sweden. Am J Clin Nutr. 2002;76:100–106. MEDLINE | http://www.adajournal.org/medline/record/ivp_00029165_76_100]. (2.) Messina MJ, Messina VL. The Dietitian's Guide to Vegetarian Diets: Issues and Applications. Gaithersburg, MD: Aspen Publishers; 1996. (3.) Am J Clin Nutr. 1994;59 (suppl):1233S-1237S. (4.) [ Ball MJ, Bartlett MA. Dietary intake and iron status of Australian vegetarian women. Am J Clin Nutr. 1999;70:353–358. | http://www.adajournal.org/medline/record/ivp_00029165_70_353]
  24. ^ Entry for "Beans, kidney, all types, mature seeds, cooked, boiled, without salt" in the USDA Nutrients database
  25. ^ http://www.iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Vitamins.ashx

[edit] Documentaries

[edit] 1990s

[edit] 2000s

[edit] 2010s

[edit] Further reading

[edit] 1980s

[edit] 1990s

  • William Harris (1993) Scientific Basis of Vegetarianism
  • Neal Pinckney (1996) Healthy Heart Handbook
  • Dean Ornish (1996) Dr. Dean Ornish's Programme for Reversing Heart Disease
  • John A. McDougall (1996) The McDougall Program for a Healthy Heart
  • George Eisman (1999) A Basic Course in Vegetarian and Vegan Nutrition
  • J. Robert Hatherill (1999) Eat To Beat Cancer

[edit] 2000s

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