||This article needs more medical references for verification or relies too heavily on primary sources. (March 2015)|
||This article possibly contains original research. (March 2015)|
Vegetarian nutrition is the set of health-related challenges and advantages of vegetarian diets.
If well-planned and fortified to balance their deficiencies, vegetarian and vegan diets can become nutritionally adequate and can be appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence. When fortified, a vegetarian diet can provide adequate protein, iron, zinc, vitamin B12, and calcium intake, though these nutrients can be dangerously low and may compromise children's health and development in non fortified vegetarian diets, and when not enough calories are consumed.
Evidence suggests that vegetarians have lower rates of coronary heart disease, obesity, hypertension, type 2 diabetes, and osteoporosis. Vegetarian diets tend to be rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium. They are generally low in saturated fat, cholesterol, and animal protein.
Effects of a vegetarian diet
The Oxford Vegetarian Study showed that the health of vegetarians compares favourably with that of meat-eaters (excluding pescetarians). British vegetarians have lower death rates than non-vegetarians, although this is at least partly due to non-dietary lifestyle factors, such as a low prevalence of smoking and the generally high socioeconomic status of vegetarians, or to aspects of the diet other than the avoidance of meat and fish.
Loma Linda University School of Public Health has conducted three cohort studies that identify the health benefits of a vegetarian diet. The University is a Seventh-day Adventist health science institution. The first study, funded by the US Public Health Service in 1958 and limited to Adventists in California, included many vegetarians. The next cohort of California Adventists, the Adventist Health Study-1 (AHS-1), collected data from 1974 to 1976. From 2002 to 2007 the Adventist Health Study-2 (AHS-2) collected dietary data from 96,000 church members from the United States and Canada. Many scientific articles have been published on the health and nutrition properties of a vegetarian diet from these cohort studies. The most recent AHS-2 study includes findings on metabolic syndrome, Vitamin D absorption and type-2 diabetes
In prospective studies of adults, compared to non-vegetarian eating patterns, vegetarian-style eating patterns have been associated with improved health outcomes—lower levels of obesity, a reduced risk of cardiovascular disease, and lower total mortality. Several clinical trials have documented that vegetarian eating patterns lower blood pressure.
On average, vegetarians consume a lower proportion of calories from fat (particularly saturated fatty acids); fewer overall calories; and more fiber, potassium, and vitamin C than do non-vegetarians. Vegetarians generally have a lower body mass index. These characteristics and other lifestyle factors associated with a vegetarian diet may contribute to the positive health outcomes that have been identified among vegetarians.
Vegetarians may avoid the negative health effects of processed red meat: A 1999 meta-study of five studies comparing vegetarian and non-vegetarian mortality rates in Western countries found that in comparison with regular meat eaters, mortality from ischemic heart disease was 34% lower in people who ate fish but not meat (pescetarians), 34% lower in ovo-lacto vegetarians, 26% lower in vegans and 20% lower in occasional meat eaters. A 2010 study found that heart disease is not linked with unprocessed red meat.
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. They also state that a lifestyle change incorporating a low fat vegetarian or vegan diet could not only prevent various degenerative diseases, such as coronary artery disease, but reverse them.
Studies of cancer have not shown clear differences in cancer rates between vegetarians and non-vegetarians. There is evidence that vegetarians tend to have a lower body mass index, lower risk of obesity, lower blood cholesterol levels, lower homocysteine levels, lower risk of high blood pressure, and lower risk of type 2 diabetes. One large prospective study found that non-meat-eaters had only half the risk of meat eaters of requiring an emergency appendectomy.
A 2012 study found that too much or too little red meat consumption is tied to anxiety and depression in women. However, another study showed that vegetarian diets are associated with healthy mood states.
Potential nutrient deficiencies
Poorly planned vegetarian diets may be low in vitamin B12, calcium, omega-3 fatty acids, vitamin D, iron, zinc, riboflavin (vitamin B2), and iodine, and poorly planned vegan diets may have particularly low intakes of vitamin B12 and calcium. Nonetheless, well-balanced vegetarian and 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. Many tools are available to help vegetarians maintain an adequate nutrient balance including several Vegetarian Diet Pyramids.
The typical vegetarian gets adequate protein as long as caloric intake is adequate and a variety of foods is eaten. Vegetarian diets tend to be lower in protein than non-vegetarian diets but typically meet or exceed daily protein intake recommendations, which is believed to be beneficial. Plant sources of protein include soy beans (and soy products such as tofu, veggie burgers, soy milk, etc.), other legumes, nuts and seeds, and grains.
Despite a widespread belief that vegetarians must eat grains and beans within a few hours of each other to make a 'complete' protein which contains all 9 "essential amino acids", this has never been substantiated by research. The protein-combining theory was brought to popular attention in Frances Moore Lappé's 1971 bestseller Diet for a Small Planet. In later editions of the book, as early as 1981, Lappé withdrew her contention that protein 'combining' is necessary.
In several studies, vegans and other vegetarians were not found to suffer from iron-deficiency more than non-vegetarians. However, while one study agreed that iron-deficiency anemia is not more common among vegetarians, they found "vegetarian children had ... reduced levels of haemoglobin and iron compared to omnivores" due "to the absence of animal iron sources with high utilizability". Another study, in India, found that "strict vegetarian mothers as well as their newborns have a greater incidence and risk of anemia and iron deficiency."
The recommended iron intake for vegetarians is 1.8 times that of nonvegetarians, because plants, dairy, and eggs contain only non-heme iron, and this is absorbed less efficiently than heme iron. Although a lower percentage of non-heme iron is absorbed, greater amounts of non-heme iron are concentrated in many non-meat sources of iron (than the amount of iron per serving in meats), and therefore, cereals, eggs, nuts, seeds, and legumes (including soy foods, peas, beans, chickpeas, and lentils) are significant sources of iron, and a well-planned vegetarian diet should not lead to iron deficiency, but fruitarianism and raw foods diets should not be pursued for infants or children. Meat, fish, and poultry (not dairy or eggs) are the only sources of heme iron; intake of heme iron may be associated with colon cancer. Non-heme iron is more sensitive to both inhibitors and enhancers of iron absorption. Vitamin C is an iron absorption enhancer. The main inhibitors for most people are phytates (e.g. legumes and grains), but other inhibitors include tannins (tea, wine), calcium and polyphenols.
Iron is an integral part of many proteins and enzymes which maintain good health. In humans, iron is an essential component of proteins involved in red blood cells' oxygen transport. Iron also helps regulate cell growth and differentiation.
Western vegetarians and vegans have not been found to suffer from overt zinc deficiencies any more than meat-eaters. However, phytates in many whole-grains and fiber in many foods may interfere with zinc absorption and marginal zinc intake has poorly understood effects. Vegetarians may need more than the US RDA (15 mg) of zinc daily if their diet is high in phytates.
Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soyfoods, nuts, peas, and seeds.
Lacto-ovo vegetarians may get vitamin B12 from eggs and dairy products (milk, cheese, etc.); for some this is adequate but some may still remain B12-deficient. According to the Academy of Nutrition and Dietetics, the form of vitamin B12 sourced from animal-products is protein-bound and not as easily digested, especially as people age, and therefore recommends B12 supplementation for everyone over the age of 50. Pregnant and lactating vegetarians (and breastfed infants if the mother's diet is not supplemented) should also use supplements, whether pills, injections, or B12-fortified foods, if they don't get adequate B12 from animal-products like eggs or dairy.
Generally, humans need 2.4-3 micrograms of B12 each day. Although some argue that developing a disease from B12 deficiency by following a sensible diet is extremely rare—less than one chance in a million, there are cases to suggest that vegetarians and vegans who are not taking vitamin B12 supplements or food fortified with B12, do not consume sufficient servings of B12 and have abnormally low blood concentrations of vitamin B12. This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B12.
It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B12 (such as nutritional yeast or other yeast extracts, vegetable stock, veggie burger mixes, textured vegetable protein, soy milks, vegetable and sunflower margarines, and breakfast cereals). B12 that is to be used in these supplements is typically grown from vegan sources (such as bacteria). Soybean and barley seeds grown in soils amended with cow dung (which is naturally rich in B12), or with pure B12 had a higher B12 content than those grown without this supplementation. There is a patent for cultivating plants in a solution containing vitamin B12 so that the crop contains more B12.
Omega-3 fatty acids
Vegetarian diets can be low in omega-3 fatty acids (O3FA). Major vegetarian 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 fish, eggs, or generous amounts of sea vegetables (seaweed) generally lack a direct source of long-chain O3FA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Vegetarian 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 vegetarian O3FA sources, to EPA and DHA. Short-term supplemental ALA has been shown to increase EPA levels but not DHA levels, suggesting poor conversion of the intermediary EPA to DHA. DHA supplements derived from DHA-rich microalgae are available, but the human body can only inefficiently convert DHA to EPA.
While there is no scientific consensus on the role of omega-3 fatty acids, they may reduce the risk of coronary heart disease, 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. 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. 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.
The human body can synthesize vitamin D when skin is exposed to ultraviolet radiation from the sun. Vegans who do not eat foods or pills fortified with synthetic vitamin D and with little exposure to the sun's ultraviolet radiation (e.g., 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.
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." 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.
- China–Cornell–Oxford Project
- Vegetarian cuisine
- Vegan nutrition
- The China Study
- American Dietetic, Association; Dietitians Of, Canada (2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association 103 (6): 748–65. doi:10.1053/jada.2003.50142. PMID 12778049.
- Black, Maureen (June 2008). "Effects of vitamin B12 and folate deficiency on brain development in children". US National Library of Medicine National Institutes of Health 29 (2 Suppl): S126–31. PMC 3137939. PMID 18709887.
- Incidence of osteoporosis in vegetarians and omnivores
- Appleby, Paul N; Thorogood, Margaret; Mann, Jim I; Key, Timothy JA (1999). "The Oxford Vegetarian Study: An overview". The American journal of clinical nutrition 70 (3 Suppl): 525S–531S. PMID 10479226.
- Appleby, Paul N; Key, Timothy J; Thorogood, Margaret; Burr, Michael L; Mann, Jim (2007). "Mortality in British vegetarians". Public Health Nutrition 5 (1): 29–36. doi:10.1079/PHN2001248. PMID 12001975.
- Adventist Health Studies
- List of scientific publications from the Adventist Health Studies
- Rizzo, N. S.; Sabate, J.; Jaceldo-Siegl, K.; Fraser, G. E. (2011). "Vegetarian Dietary Patterns Are Associated with a Lower Risk of Metabolic Syndrome: The Adventist Health Study 2". Diabetes Care 34 (5): 1225–7. doi:10.2337/dc10-1221. PMC 3114510. PMID 21411506.
- Chan, J.; Jaceldo-Siegl, K.; Fraser, G. E (2009). "Serum 25-hydroxyvitamin D status of vegetarians, partial vegetarians, and nonvegetarians: The Adventist Health Study-2". American Journal of Clinical Nutrition 89 (5): 1686S. doi:10.3945/ajcn.2009.26736X. PMID 19339396.
- Tonstad, S.; Butler, T.; Yan, R.; Fraser, G. E. (2009). "Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes". Diabetes Care 32 (5): 791–6. doi:10.2337/dc08-1886. PMC 2671114. PMID 19351712.
- United States Department of Agriculture; United States Department of Health and Human Services (December 2010). "Building Healthy Eating Patterns". Dietary Guidelines for Americans, 2010 (7th ed.). Washington, DC: U.S. Government Printing Office. pp. 43–54.
- Key, T. J.; Fraser, G. E.; Thorogood, M; Appleby, P. N.; Beral, V; Reeves, G; Burr, M. L.; Chang-Claude, J; Frentzel-Beyme, R; Kuzma, J. W.; Mann, J; McPherson, K (1999). "Mortality in vegetarians and nonvegetarians: Detailed findings from a collaborative analysis of 5 prospective studies". The American journal of clinical nutrition 70 (3 Suppl): 516S–524S. doi:10.1079/phn19980006. PMID 10479225.
- Micha, R.; Wallace, S. K.; Mozaffarian, D. (2010). "Red and Processed Meat Consumption and Risk of Incident Coronary Heart Disease, Stroke, and Diabetes Mellitus: A Systematic Review and Meta-Analysis". Circulation 121 (21): 2271–83. doi:10.1161/CIRCULATIONAHA.109.924977. PMID 20479151. Lay summary – Harvard School of Public Health (May 17, 2010).
- Segelken, Roger (2001-06-28). "China Study II: Switch to Western diet may bring Western-type diseases". Cornell Chronicle. Retrieved 2006-09-15.
- "China-Cornell-Oxford Project On Nutrition, Environment and Health at Cornell University". Division of Nutritional Sciences. Cornell University. Retrieved 2006-09-15.
- Barnard, Neal D. (2007). Dr. Neal Barnard's Program for Reversing Diabetes. New York: Rodale. pp. 40–50.
Set aside animal products
- Ornish, D.; Brown, S.E.; Billings, J.H.; Scherwitz, L.W.; Armstrong, W.T.; Ports, T.A.; McLanahan, S.M.; Kirkeeide, R.L.; Gould, K.L.; Brand, R.J. (1990). "Can lifestyle changes reverse coronary heart disease?". The Lancet 336 (8708): 129–33. doi:10.1016/0140-6736(90)91656-U. PMID 1973470.
- Goldhamer, Alan C.; Lisle, Douglas J.; Sultana, Peter; Anderson, Scott V.; Parpia, Banoo; Hughes, Barry; Campbell, T. Colin (2002). "Medically Supervised Water-Only Fasting in the Treatment of Borderline Hypertension". The Journal of Alternative and Complementary Medicine 8 (5): 643–50. doi:10.1089/107555302320825165. PMID 12470446.
- McDougall, John; Bruce, Bonnie; Spiller, Gene; Westerdahl, John; McDougall, Mary (2002). "Effects of a Very Low-Fat, Vegan Diet in Subjects with Rheumatoid Arthritis". The Journal of Alternative and Complementary Medicine 8 (1): 71–5. doi:10.1089/107555302753507195. PMID 11890437.
- Esselstyn, Caldwell B (1999). "Updating a 12-year experience with arrest and reversal therapy for coronary heart disease (an overdue requiem for palliative cardiology)". The American Journal of Cardiology 84 (3): 339–41, A8. doi:10.1016/S0002-9149(99)00290-8. PMID 10496449.
- Barnard, N. D.; Cohen, J.; Jenkins, D. J.A.; Turner-Mcgrievy, G.; Gloede, L.; Jaster, B.; Seidl, K.; Green, A. A.; Talpers, S. (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.
- Key, Timothy J.; Appleby, Paul N.; Rosell, Magdalena S. (2007). "Health effects of vegetarian and vegan diets". Proceedings of the Nutrition Society 65 (1): 35–41. doi:10.1079/PNS2005481. PMID 16441942.
- American Heart Association: Vegetarian Diets. Retrieved 4 January 2007.
- Jacka, Felice N.; Pasco, Julie A.; Williams, Lana J.; Mann, Neil; Hodge, Allison; Brazionis, Laima; Berk, Michael (2012). "Red Meat Consumption and Mood and Anxiety Disorders". Psychotherapy and Psychosomatics 81 (3): 196–8. doi:10.1159/000334910. PMID 22433903. Lay summary – PsychCentral (March 21, 2012).
- Beezhold, Bonnie L; Johnston, Carol S; Daigle, Deanna R (2010). "Vegetarian diets are associated with healthy mood states: A cross-sectional study in Seventh Day Adventist adults". Nutrition Journal 9 (1): 26. doi:10.1186/1475-2891-9-26. PMC 2887769. PMID 20515497.
- Loma Linda University Vegetarian Food Pyramid
- The Oldways Vegetarian Diet Pyramid
- Akers, Keith: But How Do You Get Enough Protein?. Compassionate Spirit. Retrieved 25 June 2010.[unreliable medical source?]
- Fontana, L; Klein, S; Holloszy, J. O. (2006). "Long-term low-protein, low-calorie diet and endurance exercise modulate metabolic factors associated with cancer risk". The American journal of clinical nutrition 84 (6): 1456–62. PMID 17158430. Lay summary – Nutra Ingredients (December 7, 2006).
- Diabetic nephropathy
- Feskanich, D; Willett, W C; Stampfer, M J; Colditz, G A (1997). "Milk, dietary calcium, and bone fractures in women: A 12-year prospective study". American Journal of Public Health 87 (6): 992–7. doi:10.2105/AJPH.87.6.992. PMC 1380936. PMID 9224182.
- Feskanich, D; Willett, W. C.; Colditz, G. A. (2003). "Calcium, vitamin D, milk consumption, and hip fractures: A prospective study among postmenopausal women". The American journal of clinical nutrition 77 (2): 504–11. PMID 12540414.
- Cumming, R. G.; Klineberg, R. J. (1994). "Case-control study of risk factors for hip fractures in the elderly". American Journal of Epidemiology 139 (5): 493–503. PMID 8154473.
- Grandison, Richard C.; Piper, Matthew D. W.; Partridge, Linda (2009). "Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila". Nature 462 (7276): 1061–4. Bibcode:2009Natur.462.1061G. doi:10.1038/nature08619. PMC 2798000. PMID 19956092. Lay summary – The Telegraph (December 3, 2009).
- Craig, Winston J.; Pinyan, Laura (2001). "Nutrients of Concern in Vegetarian Diets". In Sabate, Joan. Vegetarian Nutrition. CRC Press. pp. 299–332. ISBN 978-1-4200-3683-1.
- Lappé, Frances Moore (1981). Diet for a Small Planet. p. 162. ISBN 0-345-32120-0.
- Larsson, C. L.; Johansson, G. K. (2002). "Dietary intake and nutritional status of young vegans and omnivores in Sweden". The American journal of clinical nutrition 76 (1): 100–6. PMID 12081822.
- Messina MJ, Messina VL. The Dietitian's Guide to Vegetarian Diets: Issues and Applications. Gaithersburg, MD: Aspen Publishers; 1996.[page needed]
- Craig, W. J. (1994). "Iron status of vegetarians". The American journal of clinical nutrition 59 (5 Suppl): 1233S–1237S. PMID 8172127.
- Ball, M. J.; Bartlett, M. A. (1999). "Dietary intake and iron status of Australian vegetarian women". The American journal of clinical nutrition 70 (3): 353–8. PMID 10479197.
- Krajcovicová-Kudlácková, M; Simoncic, R; Béderová, A; Grancicová, E; Magálová, T (1997). "Influence of vegetarian and mixed nutrition on selected haematological and biochemical parameters in children". Die Nahrung 41 (5): 311–4. doi:10.1002/food.19970410513. PMID 9399258.
- Sharma, D. C.; Kiran, Raj; Ramnath, Vijaywantee; Khushiani, Krishna; Singh, P. P. (1994). "Iron deficiency and anemia in vegetarian mothers and their newborns". Indian Journal of Clinical Biochemistry 9 (2): 100–2. doi:10.1007/BF02869583.
- Nutrition Australia: FAQ on Vegetarian Diets'.' Retrieved 11 April 2007.
- Pierre, Fabrice; Peiro, Géraldine; Taché, Sylviane; Cross, Amanda J.; Bingham, Sheila A.; Gasc, Nicole; Gottardi, Gaëlle; Corpet, Denis E.; Guéraud, Françoise (2006). "New Marker of Colon Cancer Risk Associated with Heme Intake: 1,4-Dihydroxynonane Mercapturic Acid". Cancer Epidemiology Biomarkers & Prevention 15 (11): 2274–9. doi:10.1158/1055-9965.EPI-06-0085. PMID 17119057.
- Freeland-Graves, J. H.; Bodzy, P. W.; Eppright, M. A. (1980). "Zinc status of vegetarians". Journal of the American Dietetic Association 77 (6): 655–61. PMID 7440860.
- The Vegetarian Society. Information Sheet: Vitamin B12. Retrieved 26 April 2007.
- "Dietary Supplement Fact Sheet: Vitamin B12". USA.gov. Office of dietary supplements. Retrieved 14 March 2012.
- "Vitamin B12 Deficiency—the Meat-eaters’ Last Stand". McDougall Newsletter Archive Vol. 6, No. 11. Dr. McDougall. Retrieved 14 March 2012.[unreliable medical source?]
- "Vegans and the Vitamin B12 Deficiency Myth". Vegetarianism. pamrotella. Retrieved 14 March 2012.[unreliable medical source?]
- "Worried About Vitamin B12 Deficiency?". Raw Food Health. RAW FOOD HEALTH. Retrieved 14 March 2012.[unreliable medical source?]
- Hokin, B. D.; Butler, T (1999). "Cyanocobalamin (vitamin B-12) status in Seventh-day Adventist ministers in Australia". The American journal of clinical nutrition 70 (3 Suppl): 576S–578S. PMID 10479234.
- Krajčovičová-Kudláčková, M.; Blažíček, P.; Kopčová, J.; Béderová, A.; Babinská, K. (2000). "Homocysteine Levels in Vegetarians versus Omnivores". Annals of Nutrition and Metabolism 44 (3): 135–8. doi:10.1159/000012827. PMID 11053901.
- VeganHealth.org: B12 and Chronic Disease: Homocysteine. Retrieved 26 April 2007.
- Mozafar, A. (1994). "Enrichment of some B-vitamins in plants with application of organic fertilizers". Plant and Soil 167 (2): 305–311. doi:10.1007/BF00007957.
- Seed and plant containing vitamin B12 and method of producing the same
- Sanders, Thomas A.B. (2009). "DHA status of vegetarians". Prostaglandins, Leukotrienes and Essential Fatty Acids 81 (2–3): 137–141. doi:10.1016/j.plefa.2009.05.013.
- Davis, B. C.; Kris-Etherton, P. M. (2003). "Achieving optimal essential fatty acid status in vegetarians: Current knowledge and practical implications". The American journal of clinical nutrition 78 (3 Suppl): 640S–646S. PMID 12936959.
- 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.
- Remer, Thomas; Neubert, Annette; Manz, Friedrich (2007). "Increased risk of iodine deficiency with vegetarian nutrition". British Journal of Nutrition 81 (1): 45–9. doi:10.1017/S0007114599000136. PMID 10341675.
- William Harris (1993) Scientific Basis of Vegetarianism
- George Eisman (1999) A Basic Course in Vegetarian and Vegan Nutrition
- Joan Sabaté (2001) Vegetarian Nutrition
- United States Department of Agriculture. Vegetarian Diets.
- Food and Nutrition Information Center, USDA. Vegetarian Nutrition Resource List.
- Mayo Clinic. Vegetarian diet: How to get the best nutrition.
- Medline Plus. Vegetarian Diet.