Vegetarian nutrition

diets.

Evidence suggests that vegetarians are generally healthier and live longer than non-vegetarians. They have lower rates of coronary heart disease, obesity, hypertension, type 2 diabetes and some forms of cancer. 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.

However, vegetarian diets can sometimes be relatively low in protein, iron, zinc, vitamin B₁₂, calcium and other nutrients. Nonetheless, well-planned 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.

Benefits of a vegetarian diet

Vegetarian diets are usually rich in carbohydrates, omega-6 fatty acids, dietary fibre, carotenoids, folic acid, vitamin C, vitamin E, potassium and magnesium.Key TJ, Appleby PN, Rosell MS: “Health effects of vegetarian and vegan diets” ( [http://www.epic-oxford.org/publications/1368/key-et-al-2006-02-proc-nutr-soc abstract] ). "Proceedings of the Nutrition Society", 2006, 65:35-41. Accessed 4 January 2007.] They contain lower levels of saturated fat, cholesterol, and animal protein.

Studies show that the health of vegetarians compares favourably with that of non-vegetarians.Appleby PN, Thorogood M, Mann JI, Key TJ: “The Oxford Vegetarian Study: an overview”. "American Journal of Clinical Nutrition", 1999, 70:525S-531S.] British vegetarians have lower death rates than non-vegetarians,Key TJ, Appleby PN, Davey GK, Allen NE, Spencer EA, Travis RC: “Mortality in British vegetarians: review and preliminary results from EPIC-Oxford” ( [http://www.epic-oxford.org/publications/1280/key-et-al-2003-09-am-j-clin-nutr abstract] ). "American Journal of Clinical Nutrition", 2003, 78:533S-538S. Accessed 4 January 2007.] 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.Appleby PN, Key TJ, Thorogood M, Burr ML, Mann J: “Mortality in British vegetarians”. "Public Health Nutrition", 2002, 5:29-36.]

Notably, a vegetarian diet avoids the negative health effects of red meat. One review found that mortality from coronary heart disease was 24% lower in vegetarians than in nonvegetarians.Key TJ, Fraser GE, Thorogood M, Appleby PN, Beral V, Reeves G, Burr ML, Chang-Claude J, Frentzel-Beyme R, Kuzma JW, Mann J, McPherson K: “Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies”. "American Journal of Clinical Nutrition", 1999, 70:516S-524S.] 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, [http://www.adajournal.org/article/PIIS0002822303002943/fulltext “Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets”] . "Journal of the American Dietetic Association", 2003, 06. Accessed 4 January 2007.] lower risk of obesity,American Heart Association: [http://www.americanheart.org/presenter.jhtml?identifier=4777 "Vegetarian Diets"] . Accessed 4 January 2007.] 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.

Vegetarians are less likely to die by choking on food since the most common food to obstruct the airway is fish which caused about 4,500 accidents a year in the UK as of 1998. Meat, poultry and bones were cited as the next three most common causes of choking, followed by sweets and non-food objects. [ [http://www.hassandlass.org.uk/query/reports/1998.pdf Home and leisure accident report Summary of 1998 data p.16 Department of Trade and Industry (UK)] ] A 2007 report from San Diego in the US confirms that the most common cause of choking was on meat products. [ [http://www.ingentaconnect.com/content/bsc/jfo/2007/00000052/00000001/art00032 Deaths Associated with Choking in San Diego County (Abstract)] ]

Potential nutrient deficiencies

Poorly planned vegetarian diets can be relatively low in protein, iron, zinc, vitamin B₁₂, calcium, omega-3 fatty acids, retinol (vitamin A), vitamin D, riboflavin (vitamin B₂) and iodine. Vegans 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.

Protein

The typical vegetarian gets adequate protein as long as caloric intake is adequate and a variety of foods is eaten.Akers, Keith: " [http://www.vsc.org/protein.htm But How Do You Get Enough Protein?] ". Vegetarian Society of Colorado. Accessed 11 April 2007.] Vegetarian diets are usually relatively low in protein, which may be beneficial. [Food Navigator USA: [http://www.foodnavigator-usa.com/news/ng.asp?n=72611-protein-cancer "Low-protein diets could protect against cancer, says new study"] . 7 December 2006. Accessed 4 January 2007.] [ [http://www.clinicalevidence.com/ceweb/conditions/dia/0606/0606_I8.jsp Diabetic nephropathy] ]

Combining proteins

— Keith AkersDespite a widespread belief that vegetarians must eat grains and beans within a few hours of each other in order 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. [Lappé, Frances Moore (1981). "Diet for a Small Planet", p. 162. ISBN 0-345-32120-0]

Iron

Meat, fish and poultry are the only sources of heme iron; plants contain only non-heme iron, which is absorbed less efficiently by the human body. However, cereals, eggs, legumes (including peas, beans, chickpeas, lentils and soy foods) and nuts are significant sources of iron, [Nutrition Australia: " [http://www.nutritionaustralia.org/Food_Facts/FAQ/vegetarian_new_detailed_faq.asp FAQ on Vegetarian Diets] ". Accessed 11 April 2007.] so a well planned vegetarian diet should not lead to iron deficiency.

A study in the Journal of the American Dietetic Association found that while iron-deficiency anemia is not more common among vegetarians, "vegetarian children had ... reduced levels of haemoglobin and iron compared to omnivores" due "to the absence of animal iron sources with high utilizability".Krajcovicova-Kudlackova M, Simoncic R, Bederova A, Grancicova E, Magalova T: “ [http://www.adajournal.org/medline/record/MDLN.9399258 Influence of vegetarian and mixed nutrition on selected haematological and biochemical parameters in children] .” "Nahrung", October 1997, 41:311-314.]

Zinc

Western vegetarians and vegans have not been found to suffer from overt zinc deficiencies any more than meat-eaters. [Freeland-Graves J. H., Bodzy P. W., Epright M. A.: “Zinc status of vegetarians”. "Journal of the American Dietetic Association", 1980, 77:655-661] However, phytates in many whole-grains and fiber in many foods may interfere with zinc absorption and marginal zinc intake has poorly understood effects.

Vitamin B₁₂

Vitamin B₁₂ deficiency is potentially extremely serious, leading to pernicious anemia, nerve degeneration and irreversible neurological damage. A regular source of vitamin B₁₂ is particularly important for those over the age of 50 years, and pregnant and lactating women (and for breastfed infants if the mother's diet is not supplemented).

Evidence suggests that vegetarians and vegans who are not taking vitamin B₁₂ supplements or B₁₂-fortified foods do not consume sufficient servings of B₁₂ and often have abnormally low blood concentrations of vitamin B₁₂. [See, for example, Hokin BD and Butler T: “ [http://www.ajcn.org/cgi/content/full/70/3/576S 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: “ [http://content.karger.com/produktedb/produkte.asp?typ=fulltext&file=anm44135 Homocysteine Levels in Vegetarians versus Omnivores] ” in "Annals of Nutrition & Metabolism", 2000, 44:135-138; and VeganHealth.org: " [http://www.veganhealth.org/b12/hcy B12 and Chronic Disease: Homocysteine] ". Accessed 26 April 2007.] This is because, unless fortified, plant foods do not contain significant amounts of active vitamin B₁₂.

It is essential, therefore, that vegetarians consume adequate amounts of dairy products, eggs, dietary supplements or foods that have been fortified with B₁₂ (such as certain yeast extracts, vegetable stock, veggie burger mixes, textured vegetable protein, soy milks, vegetable and sunflower margarines, and breakfast cereals).The Vegetarian Society. " [http://www.vegsoc.org/info/b12.html Information Sheet: Vitamin Bssub|12] ". Accessed 26 April 2007.]

nori(Seaweed) contains B₁₂ very abundantly. [ [http://www.mext.go.jp/b_menu/shingi/gijyutu/gijyutu3/toushin/05031802/002/009.pdf ALGAE] from " [http://www.mext.go.jp/b_menu/shingi/gijyutu/gijyutu3/toushin/05031802.htm STANDARD TABLES OF FOOD COMPOSITION IN JAPAN Fifth Revised and Enlarged Edition 2005] "] However, plant sources of B₁₂ (or analogues) have not yet been shown to benefit humans. There is a patent for a cultivation method of a mycelium's enriching vitamin B₁₂ of the vegetable. [ [http://www.wikipatents.com/ca/2431442.html Seed and plant containing vitamin B12 and method of producing the same ] ]

Omega-3 fatty acids

Vegetarian sources of omega-3 fatty acids include flaxseeds and flaxseed oil, olive oil, walnuts, canola (rapeseed) oil, avocado, and eggs.

. [ [http://www.seafish.org/pdf.pl?file=seafish/file/consumerHealthInfo.pdf Revised Seafood Briefing DocOct03 ] ]

While there is no scientific consensus on the role of omega-3 fatty acids, it is generally believed that 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.

Vitamin D

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.

Iodine

According the British Journal of Nutrition there is 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." [Thomas Remer, Annette Neubert and Friedrich Manz: “ [http://docstore.ingenta.com/cgi-bin/ds_deliver/1/u/d/ISIS/34393885.1/cabi/bjn/1999/00000081/00000001/art00009/3E55FC91FC3793AE1167931465C2FF219D4F166CC9.html?link=http://www.ingentaconnect.com/error/delivery%3Bjsessionid=1270sjtai37ar.henrietta&format=html Increased risk of iodine deficiency with vegetarian nutrition] ”. "British Journal of Nutrition", 1999, 81:45-49. Accessed 4 January 2007.] Iodine, however, is usually supplied by iodized salt and other sources in first world countries.Additionally, it should be noted that any iodine found in animal products is sourced from plant life (see: ).

Riboflavin

According to the American Dietetic Association, “Some studies have shown vegans to have lower intakes of riboflavin, compared with nonvegetarians; however, clinical riboflavin deficiency has not been observed.”

References

ee also

* Nutrition
* Vegetarian cuisine
* Vegetarianism
* Veganism
* Vegan cuisine
* The China Study

Further reading

* [http://www.mayoclinic.com/invoke.cfm?id=HQ01596 Mayo Clinic's synopsis] .
* [http://www.vrg.org Vegetarian Resource Group]
* [http://www.vegparadise.com/protein.html Protein Basics Chart]
* [http://www.epic-oxford.org/gen_vegpapers.html Focus on vegetarians] research from EPIC-Oxford.

* The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-Term Health (2005) by: T. Colin Campbell ISBN 1-932100-66-0
* [http://www.earthtimes.org/articles/show/13988.html Becoming a 'Veggie' : The Smart Move]
* [http://www.nal.usda.gov/fnic/pubs/bibs/gen/vegetarian07.pdf Vegetarian Nutrition Resource List - USDA, NAL Food and Nutrition Information Center (PDF|72 KB)]