A Review of Recent Scientific Papers Related to Vegetarianism
Colorectal cancer is the third most common cancer in the United States and the second most common cause of cancer deaths. The American Cancer Society estimates that colorectal cancer caused more than 56,000 deaths in 2005. Obesity, physical inactivity, and high alcohol consumption are some of the factors associated with an increased risk of colorectal cancer. An estimated 70 percent of colorectal cancers in Western countries could be avoided by lifestyle changes. Some studies have shown that one of these changes could be switching to a vegetarian diet; vegetarians have been shown to have a lower risk of colon cancer than non-vegetarians. A recent study of more than 478,000 men and women from 10 European countries examined the effect of meat, poultry, and fish intake on colorectal cancer risk. In this group of mainly non-vegetarians, higher fish intake was associated with a lower risk of colorectal cancer; poultry consumption did not appear to affect cancer risk. People with high intakes (more than 5 ounces per day) of red meat (beef, veal, pork, and lamb) and processed meat (ham, bacon, sausage, lunch meat, etc.) had a higher risk of developing colorectal cancer than did people averaging less than an ounce of red and processed meat daily. Veggie burgers, anyone?
Cataract (clouding of the lens of the eye) is the number one cause of blindness worldwide. Currently, nearly one in five Americans age 40 or older has cataracts. Medicare spends more than $3.4 billion per year for treatment of this condition. If dietary changes could reduce the risk of developing cataracts, the impact on health care costs would be staggering. Very few studies have examined dietary risk factors for cataract.
Recently, two studies were published, one which examined fruit and vegetable consumption and cataract risk and another which examined carbohydrate consumption and cataract risk. Both studies were of middle-aged and older women. Women who ate more than 3.4 servings of fruits and vegetables daily had a slightly lower (10-15 percent) risk of developing cataracts and having surgery to remove them. While these results are modest, increased fruit and vegetable intake can’t hurt, may reduce risk of cataracts, and certainly helps to reduce the risk of many other diseases.
The second study found that higher carbohydrate intakes were associated with an increased risk of one type of cataract called cortical cataracts. Since this type of cataract represents only a small proportion of cataracts that are surgically removed, the practical implications of these results are uncertain. At this point, increasing fruit and vegetable intake appears to be one way to reduce the risk of developing cataracts.
In 1976, 1,225 vegetarians and 679 ‘health-conscious’ non-vegetarians in Germany were recruited for a long-term study. The group being studied included vegans (3 percent), lacto-ovo vegetarians (61 percent), and non-vegetarians (36 percent). Twenty-one years later, researchers determined which of the subjects had died and what had caused their deaths. Overall, this group had a much lower rate of death than the general population, mainly because of many fewer deaths from heart disease. Vegetarians had lower rates of death from heart disease than non-vegetarians, even in this study where non-vegetarians were health-conscious. Death rates from cancer were similar in both groups. Individuals who were moderately or highly physically active were less likely to die from cancer or heart disease than those who were more sedentary. There was a trend of increased risk of dying from heart disease as meat consumption increased. Eating fish more than once a month was also associated with an increased risk of death from heart disease. Many results of this study are in accord with studies of British vegetarians and of Seventh-day Adventist vegetarians in the United States.
Recently, a study of men and women living in British Columbia, Canada, showed that vegetarians were more physically active than non-vegetarians and were more likely to consider improving or maintaining their health when choosing foods. This was a population-based study using the British Columbia Health Registry, so the participants mirror the general British Columbian population. This study is also significant because few population-based studies have compared dietary intake and behavior between vegetarians and non-vegetarians.
Of the 1,817 participants, approximately 6 percent identified themselves as vegetarian. However, of this 6 percent, 75 percent consumed fish at least occasionally, 58 percent consumed poultry at least occasionally, and 22 percent consumed red meat at least occasionally. Vegetarians in this population tended to be mainly lacto-ovo vegetarians, and they tended to be younger, female, and low-income in status. Female vegetarians tended to engage in moderate to strenuous physical activity most days of the week and were less likely to be classified as overweight or obese compared to female non-vegetarians. Both male and female vegetarians were less likely to be smokers.
Both male and female vegetarians had more fiber, magnesium, and potassium in their diets and used more supplements than non-vegetarians. This study also found female vegetarians were less likely to have inadequate intakes of folate, vitamin B6, thiamin, and vitamin C compared to non-vegetarians. Vegetarians of both genders consumed more fruits and vegetables and were more likely to consider health when choosing or avoiding food compared to non-vegetarians. Taken altogether, vegetarians were, as readers might expect, more health conscious as evidenced by their increased awareness and practice of dietary and lifestyle considerations that are important in maintaining good health.
This review of a study examining the dietary habits and lifestyle choices of British Columbian vegetarians was written by Melissa Wong, VRG Dietetic Intern.
The Vegetarian Journal published here is not the complete issue, but these are excerpts from the published magazine. Anyone who wishes to see everything should subscribe to the magazine.
Thanks to volunteer Stephanie Schueler for converting this article to HTML.
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