Personal and professional correlates of US medical students' vegetarianism

Nutrition Research Newsletter, Feb, 2007

Plant-based and vegetarian diets are potentially therapeutic, and are correlated with some physicians' likelihood to provide patient nutrition counseling. Vegetarian, versus omnivorous, diets have been associated in large survey and prospective cohort studies with lower body weights and lower rates of overweight BMIs, fewer diabetic complications and less self-reported diabetes, and lower mortality from ischemic heart disease and certain cancers. In US clinical intervention trials, a low-fat vegetarian diet has been shown (even without the effects of exercise) to reduce diabetic complications, serum cholesterol, and symptoms of rheumatoid arthritis and fibromyalgia. In addition to these findings, vegetarianism has been associated with eating less saturated fat, and more complex carbohydrates, fruits and vegetables, fiber, folate, and other phytochemicals.

Exploring the characteristics associated with vegetarianism in a health-educated population such as medical students will help determine if this dietary trend is associated with other healthful personal and clinical practices. More healthful dietary patterns are associated with increased nutrition counseling attitudes and practices of physicians and medical students. Specifically, nutrition counseling is more frequent among those following a "prudent diet," eating less fat, and eating more fruits and vegetables. The Women Physicians' Health Study is a study of 4501 women physicians' personal and clinical health practices. Women vegetarian physicians in this study report performing nutrition counseling for patients more frequently than do nonvegetarian women physicians. Some small studies demonstrate that training interventions may improve both medical students' personal dietary behaviors and disease-prevention counseling attitudes. Building on these preliminary associations, the authors of this paper implemented the Healthy Doe-Healthy Patient study, to describe medical students' attitudes and behaviors regarding personal and clinical prevention, and the relationship between their personal and clinical practices. The preliminary objective of this article is to provide vegetarian prevalence data on US medical students throughout their education; this includes comparing various definitions of, and reasons for, vegetarianism. The primary objective of this article is to examine dietary and other personal health characteristics, as well as mentoring and clinical characteristics, for association with US medical students' vegetarianism.

All Class of 2003 medical students at 17 representative US schools were eligible for participation in this study at each of three questionnaire administrations (given at freshman orientation in 1999, at ward orientation, and during senior year).

Within each Healthy Doe-Healthy Patient study questionnaire, a brief FFQ queried consumption (from zero to six times per day, week, or month) of 40 food/beverage and three supplement items. Self-identified vegetarianism was assessed on each Healthy Doe-Healthy Patient questionnaire: "Do you consider yourself a vegetarian? (yes, no)." Vegetarianism was secondarily characterized by a reported zero intake of meat items on each FFQ administration, where "meat" refers to all nonfowl, nonfish flesh.

During medical school, 7.2% of students self-identified as vegetarians; this percentage declined over time. Those who were vegetarians for health reasons (66% of vegetarians) ate more fruits and vegetables than those who were vegetarians for non_health reasons. Vegetarians were more likely than nonvegetarians to eat more fruits and vegetables; be women; be Hindu, Buddhist, or Seventh Day Adventist; be politically liberal; have a BMI d"25; or, as freshmen, to perceive nutrition counseling as highly relevant to their intended practices. Vegetarian students were no more likely to counsel patients about nutrition than were nonvegetarians.

The prevalence of vegetarianism was higher among medical students than among other US adults. This sample was 7.2% vegetarian and nationally, in 2000, the estimated prevalence of self-identified vegetarianism was 2.5%. In 2003, the percentage of 18- to 24-year-olds reporting never eating meat, fish, or fowl was also smaller (2.0%) than the analogous percentage of similarly aged medical students in this study (4.0%). The percentage of vegetarians declined during medical school; this parallels students' declines during medical school in other health-related habits: fruit and vegetable consumption, vitamin/mineral supplement use, and physical exercise. Vegetarianism prevalence among freshmen was not maintained despite increased medical education, new data from clinical interventions and reviews confirming the benefits of vegetarian diets, and other secular trends. The declines in personal healthful behaviors may reflect the disruption clinical rotations create, for example, in students' typical or preferred eating patterns.

Plant-based diets are healthful, and vegetarian diets share many of these health benefits (but also carry some risks). The prevalence of vegetarianism in a highly health-educated population, such as medical students, may provide a benchmark for such health habits in young adults. Although the prevalence of vegetarianism was higher among US medical students than among other young US adults, the percentage of medical student vegetarians decreased during their training. In addition, although freshmen vegetarians were more likely to think that nutrition counseling would be highly relevant to their intended specialty, by ward orientation their opinion on the relevance of such counseling was indistinguishable from that of their omnivorous peers. Regarding counseling frequency, this sample was not large enough to detect true variation between vegetarians and nonvegetarians. Fewer than 210 senior students of any dietary regimen reported usually/ always counseling on nutrition issues. Among the 6% of seniors who reported being vegetarian, only 13% (n=10) also reported frequently providing nutrition counseling to their typical general medicine patients. Although documenting the association between nutrition counseling and vegetarianism may merit larger studies, the researchers found that vegetarian (versus omnivorous) medical students were less likely to be overweight, more likely to eat more fruits and vegetables, and somewhat less likely to binge drink or use tobacco.