Vegan for Life - Jack Norris [67]
• Some plant foods, like olives and nuts, are high in total fat, but they typically contain healthful types of fat.
• Plant foods are excellent sources of nutrients, such as folate, potassium, and vitamins C and E, all of which may be related to lower risks for chronic disease.
The research on diet and chronic disease is complex and conflicting, though, and trying to find solid proof for the benefits of vegetarian diets—and especially vegan diets—hasn’t been as easy as you might expect.
RESEARCH ON VEGETARIANS AND VEGANS
Much of the available information about the health effects of vegetarian diets comes from just a few large epidemiologic studies. (These studies are expensive, so there aren’t very many of them.)
• The European Prospective Investigation into Cancer and Nutrition-Oxford (EPIC-Oxford) in the United Kingdom has 65,429 participants including a fairly high number of vegetarians.
• A study of Seventh-day Adventists, the AHS-2, started in 2002 and had 96,194 participants as of 2007. It includes subjects from all fifty states and Canada and has provided preliminary findings based on questionnaires filled out by participants. Seventh-day Adventists are the only group of vegetarians or vegans from the United States whose disease rates have been studied. The Adventist church promotes a vegetarian diet to its members, and 38 percent of the AHS-2 study participants follow a vegetarian diet. Because Adventists also have low rates of smoking and drinking, they are a good population in which to compare vegetarians with meat-eaters.
• We also have findings from an analysis of five other studies that includes vegetarians from the United Kingdom, the United States, and Germany.
HEART DISEASE
People who eat plant-based diets consume less saturated fat and cholesterol and more of the compounds that protect against heart disease. One analysis of five large studies showed that the risk of dying from heart disease was 24 percent lower for vegetarians compared with meat-eaters.1
In addition, a number of studies have shown that adopting a vegetarian diet lowers blood cholesterol and the rate of heart disease (we’ll look at this more closely in Chapter 13). There is good evidence that vegetarians have lower blood-cholesterol levels than meat-eaters and that vegans have the lowest blood-cholesterol levels of all.
The table below compares cholesterol levels in vegans, omnivores, lacto-ovo vegetarians, and people who eat fish but no other types of meat to desirable levels recommended by the U.S. government’s National Cholesterol Education Program.
AVERAGE CHOLESTEROL AND TRIGLYCERIDE LEVELS*
2
The levels of LDL-cholesterol and HDL-cholesterol matter more than total cholesterol. LDL is the so-called “bad” cholesterol that is associated with a higher risk of heart disease. HDL-cholesterol is the “good” or protective form of cholesterol. The ratio of total cholesterol to HDL cholesterol is the best indicator of risk; the lower the ratio, the better.
Total cholesterol in vegans tends to be well below the upper limit of 200 milligrams, and vegans also have low LDL-cholesterol levels. Although they have lower levels of protective HDL-cholesterol, their ratio of total to HDL-cholesterol is better than that of lacto-ovo vegetarians, fish eaters, and meat-eaters. Vegans also have lower triglycerides, a type of fat that is linked to higher risk for heart disease.
HYPERTENSION
Interest in the blood pressure–lowering effect of a vegetarian diet dates back to the early part of the twentieth century. In 1926, one researcher reported that the blood pressure of vegetarian college students increased within two weeks of adding meat to their diets.3 More recent studies of Seventh-day Adventists show that vegetarians have lower blood pressures and also lower rates of hypertension than omnivores. 4 Some data indicate that vegans have lower blood pressures than lacto-ovo vegetarians. In one British study, meat-eaters were 2½ times as likely as vegans to suffer from hypertension.5