Vegetarian Foods: Powerful for Health
World-renowned figures as diverse as philosophers Plato and Nietzsche, political leaders Benjamin Franklin and Gandhi, and pop icons Paul McCartney and Bob Marley have all advocated a vegetarian diet. Science is also on the side of vegetarianism. Multitudes of studies have demonstrated the remarkable health benefits of a vegetarian diet.
“Vegetarian” is defined as avoiding all
animal flesh, including fish and poultry. Vegetarians who avoid
flesh, but do eat animal products such as cheese, milk, and
eggs, are ovo-lacto-vegetarians (ovo = egg; lacto =
milk, cheese, etc.). The ranks of those who abstain from
all animal products are rapidly growing; these people
are referred to as pure vegetarians or vegans.
Scientific research shows that health benefits increase as the amount
of food from animal sources in the diet decreases, so
vegan diets are the healthiest overall.
Preventing Cancer
Vegetarian diets—naturally low in saturated
fat, high in fiber, and replete with cancer-protective
phytochemicals—help to prevent cancer. Large studies in
England and Germany have shown that vegetarians are
about 40 percent less likely to develop cancer compared
to meat-eaters.1-3 In the United States, studies of
Seventh-Day Adventists have shown significant reductions
in cancer risk among th
ose who avoided meat.4,5
Similarly, breast cancer rates are dramatically lower
in nations, such as China, that follow plant-based diets.6
Interestingly, Japanese women who follow Western-style, meat-based
diets are eight times more likely to develop breast cancer
than women who follow a more traditional plant-based
diet.7 Meat and dairy products contribute to
many forms of cancer, including cancer of the colon,
breast, ovaries, and prostate.
Harvard studies that included tens of thousands of
women and men have shown that regular meat consumption
increases colon cancer risk by roughly 300 percent.8,9
High-fat diets also encourage the body’s production of
estrogens, in particular, estradiol. Increased levels of
this sex hormone have been linked to breast cancer. A
recent report noted that the rate of breast cancer among
premenopausal women who ate the most animal (but not
vegetable) fat was one-third higher than that of women who ate the
least animal fat.10 A separate study from Cambridge University also linked diets high in saturated fat to breast cancer.11
One study linked dairy products to an increased risk of
ovarian cancer. The process of breaking down the
lactose (milk sugar) into galactose evidently damages
the ovaries.12 Daily meat consumption triples
the risk of prostate enlargement. Regular milk consumption doubles
the risk and failure to consume vegetables regularly nearly
quadruples the risk.13
Vegetarians avoid the animal fat linked to cancer
and get abundant fiber, vitamins, and phytochemicals that help
to prevent cancer. In addition, blood analysis of
vegetarians reveals a higher level of “natural killer
cells,” specialized white blood cells that attack cancer
cells.14
Beating Heart Disease
Vegetarian diets also help prevent heart disease.
Animal products are the main source of saturated fat and the
only source of cholesterol in the diet. Vegetarians
avoid these risky products. Additionally, fiber helps
reduce cholesterol levels15 and animal
products contain no fiber. When individuals switch to a
high-fiber, low-fat diet their serum cholesterol levels often
drop dramatically.16,17 Studies have demonstrated that a
low-fat, high-fiber, vegetarian or vegan diet combined
with stress reduction techniques, smoking cessation, and
exercise, or combined with prudent drug intervention,
could actually reverse atherosclerosis—hardening of the
arteries.18,19 Heart diets that include lean meat, dairy
products, and chicken are much less effective, usually only slowing
the process of atherosclerosis.
Lowering Blood Pressure
In the early 1900s, nutritionists noted that people who ate no meat had lower blood pressure.20
They also discovered that vegetarian diets could,
within two weeks, significantly reduce a person’s blood
pressure.21 These results were evident regardless
of the sodium levels in the vegetarian diets. People who follow
vegetarian diets typically have lower blood pressure.22-24
No one knows exactly why vegetarian diets work so well,
but probably cutting out meat, dairy products, and
added fats reduces the blood’s viscosity (or
“thickness”) which, in turn, brings down blood pressure.25
Plant products are generally lower in fat and sodium
and have no cholesterol at all. Vegetables and fruits are
also rich in potassium, which helps lower blood pressure.
Preventing and Reversing Diabetes
Non-insulin-dependent (adult-onset) diabetes can be
better controlled and sometimes even eliminated through a
low-fat, vegetarian diet along with regular exercise.26
Such a diet, low in fat and high in fiber and complex
carbohydrates, allows insulin to work more effectively.
The diabetic person can more easily regulate glucose
levels. While a vegetarian diet cannot eliminate the need
for insulin in people with type 1 (insulin-dependent) diabetes,
it can often reduce the amounts of insulin used. Some
scientists believe that insulin-dependent diabetes may
be caused by an auto-immune reaction to dairy proteins.27,28
Gallstones, Kidney Stones, and Osteoporosis
Vegetarian diets have been shown to reduce one’s
chances of forming kidney stones and gallstones. Diets that are
high in protein, especially animal protein, tend to
cause the body to excrete more calcium, oxalate, and
uric acid. These three substances are the main
components of urinary tract stones. British researchers
have advised that persons with a tendency to form kidney stones
should follow a vegetarian diet.29 The American
Academy of Family Physicians notes that high animal
protein intake is largely responsible for the high
prevalence of kidney stones in the United States and
other developed countries and recommends protein restriction for
the prevention of recurrent kidney stones.30
Similarly, high-cholesterol, high-fat diets—the
typical meat-based diet—are implicated in the formation of
gallstones. The consumption of meaty diets, compared to
vegetarian diets, has been shown to nearly double the
risk of gallstones in women.31
For many of the same reasons, vegetarians are at a
lower risk for osteoporosis. Since animal products force
calcium out of the body, eating meat can promote bone
loss. In nations with mainly vegetable diets (and
without dairy product consumption), osteoporosis is less
common than in the U.S.,even when calcium intake is
also less than in the U.S.32 Calcium is important,
but there is no need to get calcium from dairy products. For more
information on protecting your bones, contact PCRM for
additional reference materials or visit StrongBones.org.
Asthma
A 1985 Swedish study demonstrated that individuals
with asthma practicing a vegan diet for a full year have a
marked decrease in the need for medications and in the
frequency and severity of asthma attacks. Twenty-two of
the 24 subjects reported improvement by the end of the
year.33
Common Concerns
Some people still worry about whether a vegetarian
diet can provide all essential nutrients. However, it is very
easy to have a well-balanced diet with vegetarian
foods, since these foods provide plenty of protein.
Careful combining of foods is not necessary. Any normal
variety of plant foods provides more than enough protein
for the body’s needs. Although there is somewhat less
protein in a vegetarian diet than a meat-eater’s diet,
this is actually an advantage. Excess protein has been linked to
kidney stones, osteoporosis, and possibly heart disease and
some cancers. A diet focused on beans, whole grains, and
vegetables contains adequate amounts of protein without
the “overdose” most meat-eaters get.
Calcium is easy to find in a vegetarian diet. Many
dark green leafy vegetables and beans are loaded with
calcium, and some orange juices, non-dairy “milks,” and
cereals are calcium-fortified. Iron is plentiful in
whole grains, beans, and fruits.
Vitamin B12
Vitamin B12 is a genuine issue for vegans,
although very easy to deal with. Found mainly in animal
products, small amounts may be found in plant products
due to bacterial contamination.34,35 However,
these plant and fermented foods, such as spirulina, sea
vegetables, tempeh, and miso, do not provide an active and reliable
source,36 so vitamin B12 must be obtained elsewhere in the diet. Regular intake of vitamin B12
is important to meet nutritional needs. Good sources
include all common multiple vitamins (including vegetarian
vitamins), fortified cereals, nutritional yeast, and fortified
soymilk. It is especially important for pregnant women,
breast-feeding mothers, and children to get enough
vitamin B12.
Special Concerns: Pregnancy, Infants, and Children
During pregnancy, nutritional needs increase. The
American Dietetic Association has found vegan diets adequate
for fulfilling nutritional needs during pregnancy, but
pregnant women and nursing mothers should supplement
their diets with vitamins B12 and D.36
Most doctors also recommend that pregnant women supplement
their diet with iron and folic acid, although vegetarians normally
consume more folic acid than meat-eaters.
Vegetarian women have a lower incidence of pre-eclampsia
in pregnancy and significantly more pure breast milk.
Analyses of vegetarians’ breast milk show that the
levels of environmental contaminants in their milk are
much lower than in non-vegetarians.37 Studies
have also shown that in families with a history of food
allergies, when women abstain from allergenic foods, including milk,
meat, and fish, during pregnancy, they are less likely to
pass allergies onto the infant.38 Mothers who
drink milk pass cow antibodies along to their nursing
infants through their breast milk. These antibodies can
cause colic.
Vegetarian children also have high nutritional needs,
but these are met within a vegetarian diet. A vegetarian
menu is life extending. As young children, vegetarians
may grow more gradually, reach puberty somewhat later,
and live substantially longer than do meat-eaters.
Further Reading
For more information on vegetarian diets, PCRM recommends:
• Breaking the Food Seduction, by Neal Barnard, M.D.
• Foods That Fight Pain, by Neal Barnard, M.D.
• Eat Right, Live Longer, by Neal Barnard, M.D.
• Food for Life, by Neal Barnard, M.D.
• The McDougall Plan, by John McDougall, M.D.
• Dr. Dean Ornish’s Program for Reversing Heart Disease, by Dean Ornish, M.D.
References• Breaking the Food Seduction, by Neal Barnard, M.D.
• Foods That Fight Pain, by Neal Barnard, M.D.
• Eat Right, Live Longer, by Neal Barnard, M.D.
• Food for Life, by Neal Barnard, M.D.
• The McDougall Plan, by John McDougall, M.D.
• Dr. Dean Ornish’s Program for Reversing Heart Disease, by Dean Ornish, M.D.
1.Thorogood M, Mann J, Appleby P, McPherson K. Risk of death from cancer and ischaemic heart disease in meat and non-meat eaters. Br Med J. 1994;308:1667-1670.
2. Chang-Claude J, Frentzel-Beyme R, Eilber U. Mortality patterns of German vegetarians after 11 years of follow-up. Epidemiology. 1992;3:395-401.
3. Chang-Claude J, Frentzel-Beyme R. Dietary and lifestyle determinants of mortality among German vegetarians. Int J Epidemiol. 1993;22:228-236.
4. Phillips RL. Role of lifestyle and dietary habits in risk of cancer among Seventh-Day Adventists. Cancer Res. (Suppl) 1975;35:3513-3522.
5. Barnard ND, Nicholson A, Howard JL. The medical costs attributable to meat consumption. Prev Med. 1995; 24:646-655.
6. Campbell, TC, Chen J. Diet and chronic degenerative diseases: Perspectives from China. Am J Clin Nutr. 1994;59:1153S–1161S.
7. Trichopoulos D, Yen S, Brown J, Cole P, MacMahon B. The effect of westernization on urine estrogens, frequency of ovulation, and breast cancer risks: a study in ethnic Chinese women in the Orient and in the U.S.A. Cancer. 1984;53:187-192.
8. Giovannucci E, Rimm EB, Stampfer MJ, Colditz GA, Ascherio A, Willett WC. Intake of fat, meat, and fiber in relation to risk of colon cancer in men. Cancer Res. 1994;54:2390-2397.
9. Willett WC, Stampfer MJ, Colditz GA, Rosner BA, Speizer FE. Relation of meat, fat, and fiber intake to the risk of colon cancer in a prospective study among women. N Engl J Med. 1990;323:1664-1672.
10. Cho E, Speigelman D, Hunter DJ, Chen WY, Stampfer MJ, Colditz GA, Willett WC. Premenopausal fat intake and risk of breast cancer. J Natl Cancer Inst. 2003;95:1079-1085.
11. Bingham SA, Luben R, Welch A, Wareham N, Khaw KT, Day N. Are imprecise methods obscuring a relation between fat and breast cancer? Lancet. 2003;362:212-214.
12. Cramer DW, Harlow BL, Willett WC. Galactose consumption and metabolism in relation to the risk of ovarian cancer. Lancet. 1989;2:66-71.
13. Araki H, Watanabe H, Mishina T, Nakao M. High-risk group for benign prostatic hypertrophy. Prostate. 1983;4:253-264.
14. Malter M, Schriever G, Eilber U. Natural killer cells, vitamins, and other blood components of vegetarian and omnivorous men. Nutr Cancer. 1989;12:271-278.
15. Sacks FM, Castelli WP, Donner A, Kass EH. Plasma lipids and lipoproteins in vegetarians and controls. N Engl J Med. 1975;292:1148-1152.
16. Barnard RJ, Inkeles SB. Effects of an intensive diet and exercise program on lipids in postmenopausal women. Women’s Health Issues. 1999;9:155-161.
17. Barnard ND, Scialli AR, Bertron P, Hurlock D, Edmonds K, Talev L. Effectiveness of a low-fat vegetarian diet in altering serum lipids in healthy premenopausal women. Am J Cardiol. 2000;85:969-972.
18. Ornish D, Brown SE, Scherwitz LW. Can lifestyle changes reverse coronary heart disease? Lancet. 1990;336:129-133.
19. Esselstyn CB Jr, Ellis SG, Medendorp SV, Crowe TD. A strategy to arrest and reverse coronary artery disease: a 5-year longitudinal study of a single physician’s practice. J Fam Pract. 1995;41:560-568.
20. Salie F. Influence of vegetarian food on blood pressure. Med Klin. 1930;26:929-931.
21. Donaldson AN. The relation of protein foods to hypertension. Calif West Med. 1926;24:328-331.
22. Rouse IL, Beilin LJ. Editorial review: vegetarian diet and blood pressure. J Hypertension. 1984;2:231-240.
23. Lindahl O, Lindwall L, Spangberg A, Stenram A, Ockerman PA. A vegan regimen with reduced medication in the treatment of hypertension. Br J Nutr. 1984;52:11-20.
24. Appleby PN, Davey GK, Key TJ. Hypertension and blood pressure among meat eaters, fish eaters, vegetarians and vegans in EPIC-Oxford. Public Health Nutr. 2002;5:645-654.
25. Ernst E, Pietsch L, Matrai A, Eisenberg J. Blood rheology in vegetarians. Br J Nutr. 1986;56:555-560.
26. Nicholson AS, Sklar M, Barnard ND, et al. Toward improved management of NIDDM: A randomized, controlled, pilot intervention using a low-fat, vegetarian diet. Prev Med. 1999;29:87-91.
27. Scott FW. Cow milk and insulin-dependent diabetes mellitus: is there a relationship? Am J Clin Nutr. 1990;51:489-491.
28. Karjalainen J, Martin JM, Knip M, et al. A bovine albumin peptide as a possible trigger of insulin-dependent diabetes mellitus. N Engl J Med. 1992;327:302-307.
29. Robertson WG, Peacock M, Heyburn PJ. Should recurrent calcium oxalate stone formers become vegetarians? Br J Urol. 1979;51:427-431.
30. Goldfarb DS, Coe FL. Prevention of Recurrent Nephrolithiasis. Am Fam Physician. 1999;60:2269–2276.
31. Pixley F, Wilson D, McPherson K, Mann J. Effect of vegetarianism on development of gall stones in women. Br Med J (Clin Res Ed). 1985;291:11-12.
32. Hegsted DM. Calcium and osteoporosis. J Nutr. 1986;116:2316-2319.
33. Lindahl O, Lindwall L, Spangberg A, Stenram A, Ockerman PA. Vegan regimen with reduced medication in the treatment of bronchial asthma. J Asthma. 1985;22:45-55.
34. Herbert V. Vitamin B-12: plant sources, requirements, and assay. Am J Clin Nutr. 1988;48:852-858.
35. Rauma A, Torronen R, Hanninen O, Mykkanen H. Vitamin B-12 status of long-term adherents of a strict uncooked vegan diet (“living food diet”) is compromised. J Nutr. 1995;125:2511-2515.
36. Position of the American Dietetic Association: vegetarian diets. J Amer Diet Assoc. 2003;103(6):748-765.
37. Hergenrather J, Hlady G, Wallace B, Savage E. Pollutants in breast milk of vegetarians (letter). N Engl J Med. 1981;304:792.
38. Allergies in infants are linked to mother’s diets. New York Times, 30 August 1990.
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