Sample Online Lesson:
WHAT IS A VEGETARIAN DIET?

Health Benefits of a Vegetarian Diet

If you, one of your friends, or a family member decided to become a vegetarian, what would your first reaction be?   What will you eat?  How will you go out to restaurants?  As someone who is interested in health and nutrition, your reaction may be different from others'.   Where will you get your protein?  Your iron?  Your calcium?  The general public and some health professionals often worry that vegetarian diets are lacking in many nutrients and suggest that they have to be carefully planned, with every bite monitored to be safe and nutritionally adequate.  What most people don't realize is that vegetarian diets not only contain all the vitamins (with the exception of vitamin B₁₂ for vegans, which we will discuss in another lecture), minerals, and protein we need, but they also help prevent and treat diseases.  Some effort is required to meet all your nutrient needs on any type of diet.  Hopefully, after you complete this course, some of the myths of vegetarian diets will be dispelled.  And, if someone you know decides to become a vegetarian, your reaction will be "You're eating the healthiest diet around!"

Below is an overview of some of the top diseases in the United States and how a vegetarian diet can treat and prevent them.  In later lectures, we will cover these topics in more detail.

Preventing Cancer

A vegetarian diet helps prevent cancer.  Numerous epidemiological and clinical studies have shown that vegetarians are nearly 50 percent less likely to die from cancer than non-vegetarians.¹ Similarly, breast cancer rates are dramatically lower in nations such as China that follow primarily plant-based diets.  Interestingly, Japanese women who follow Western-style, meat-based diets are eight times more likely to develop breast cancer than those women who follow a more traditional plant-based diet.² Vegetarians also have lower rates of colon cancer than meat-eaters.¹ Animal products are usually high in fat and always devoid of fiber.  Meat and dairy products contribute to many forms of cancer, including cancer of the colon, breast, and prostate.  Colon cancer has been directly linked to meat consumption.  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.  One recent study linked dairy products to an increased risk of ovarian cancer.  The process of breaking down the milk sugar lactose into galactose seems to damage the ovaries.³ Numerous studies have also examined the correlation between diet and prostate cancer, finding a possible link between high-fat diets and diets high in dairy products.

Vegetarians avoid the animal fat linked to cancer and get abundant fiber and vitamins that help prevent the disease.  In addition, blood analyses of vegetarians reveal a higher level of Natural Killer cells, specialized white blood cells that attack cancer cells.⁴

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 levels,⁵ and animal products contain no fiber.  Dr. Dean Ornish demonstrated that a low-fat, high-fiber, vegetarian diet combined with stress reduction techniques, smoking cessation, and exercise could actually reverse atherosclerosis.⁶ Dr. Caldwell Esselstyn found similar results using a low-fat, vegetarian diet paired with medication.⁷  "Heart-healthy" diets that include animal products 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.⁷  It was also discovered that vegetarian diets, within two weeks, could significantly reduce a person's blood pressure.⁸ These results were evident regardless of the sodium levels in the meat-free diets.

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.   Because such a diet is low in fat and high in fiber and complex carbohydrates, it 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 insulin-dependent (childhood-onset) 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.^9,10

Gallstones, Kidney Stones, and Osteoporosis

Vegetarian diets have been shown to reduce a person'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.¹¹  Similarly, high-cholesterol, high-fat diets—the typical meat-based diet—are implicated in the formation of gallstones.

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 vegetarian diets (and without dairy product consumption), osteoporosis is less common than in the United States—even when calcium intake is also less than in the United States.¹² Calcium is important, but there is no need to get calcium from dairy products.  We will talk more about calcium in a later lecture.

Asthma

A 1985 Swedish study demonstrated that asthmatics who follow a vegan diet for a full year have a marked decrease in their need for medications and in their frequency and severity of asthma attacks.  Twenty-two of the 24 subjects reported improvement by the end of the year.¹³ Dairy allergies may be part of the reason.

Common Concerns

Some people still worry about the ease with which a vegetarian diet can provide all essential nutrients.  The fact is, it is very easy to have a well-balanced diet with vegetarian foods.  They provide plenty of protein, and 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 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 address.  Traditionally, getting this vitamin has not been difficult.  In cultures with plant-based diets, the microorganisms that produce B₁₂ grow in the soil and cling to root vegetables, and traditional Asian miso and tempeh contain large amounts of the vitamin.  But, with industrialized production and improved hygiene, this source of B₁₂ has been eliminated.  Meat-eaters get B₁₂ through microorganisms living in the animals they eat.

Although cases of B₁₂ deficiency are very uncommon, it is important to ensure a reliable source of the vitamin.  Good sources include all common multiple vitamins (including vegetarian vitamins), fortified cereals, and fortified soymilk.  It is especially important for pregnant women and breast-feeding mothers 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.  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 purer breast milk.  Analyses of vegetarians' breast milk show that the levels of environmental contaminants in their milk are much lower than in non-vegetarians.¹⁴ 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.¹⁵ Mothers who drink milk pass cow antibodies that can cause colic along to their nursing infants through their breast milk.

Vegetarian children also have high nutritional needs, but, these, too, are met within a vegetarian diet.  Do be sure to include a reliable source of vitamin B₁₂ in the diet.

References
1.  Phillips RL.  Role of lifestyle and dietary habits in risk of cancer among Seventh-day Adventists.  Cancer Res (Suppl) 1975;35:3513-22.
2.  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;53:187-92.
3.  Cramer DW, Harlow BL, Willett WC.  Galactose consumption and metabolism in relation to the risk of ovarian cancer.  Lancet 1989;2:66-71.
4.  Malter M, Schriever G, Eilber U.  Natural killer cells, vitamins, and other blood components of vegetarian and omnivorous men.  Nutr Cancer 1989;12:271-8.
5.  Sacks FM, Castelli WP, Donner A, Kass EH.  Plasma lipids and lipoproteins in vegetarians and controls.  N Engl J Med 1975;292:1148-52.
6.  Ornish D, Brown SE, Scherwitz LW.  Can lifestyle changes reverse coronary heart disease?  Lancet 1990;336:129-33.
7.  Esselstyn CB Jr. Updating a 12-year experience with arrent and reversal therapy for coronary artery disease (an overdue requiem for palliative cardiology). Am J Cardio 1999;84:339-41.
8.  Salie F.  Influence of vegetarian food on blood pressure.  Med Klin 1930;26:929-31.
9. Donaldson AN.  The relation of protein foods to hypertension.  Calif West Med 1926;24:328-31.
10.  Scott FW.  Cow milk and insulin-dependent diabetes mellitus: is there a relationship?  Am J Clin Nutr 1990;51:489-91.
11.  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;327:302-7.
12.  Robertson WG, Peacock M, Heyburn PJ.  Should recurrent calcium oxalate stone formers become vegetarians?  Br J Urol 1979;51:427-31.
13.  Hegsted DM.  Calcium and osteoporosis.  J Nutr 1986;116:2316-9.
14.  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.
15.  Hergenrather J, Hlady G, Wallace B, Savage E.  Pollutants in breast milk of vegetarians (letter).  N Engl J Med 1981;304:792.
16.  Allergies in infants are linked to mother's diets.  New York Times, 30 August 1990.

Home  |  Sample Online Lesson Topics