Scientific Update

How often do you think high school students in the United States eat fruits or vegetables? If you guessed ‘once a day’, you'd be close to reality. On average, high school students eat fruits 1.2 times daily and vegetables 1.2 times a day. Even more sobering is the finding that a third of high school students don’t even eat one vegetable a day, and more than a quarter don't even eat one serving of fruit. The vegetable category does include potatoes but does not include fries or chips. A minimum recommendation is approximately 1 1/2 servings of fruit and 2 1/2 servings of vegetables for high school girls and 2 servings of fruit and 3 servings of vegetables for boys. Hopefully, vegetarian students do better than the more than 11,000 high school students in this study. One suggestion for increasing students' fruit and vege-table intake is to have more salad bars in schools. The Let’s Move Salad Bars to Schools initiative has a goal of placing 6,000 salad bars in schools in three years.

Several studies have suggested that individuals with eating disorders decide to become ‘vegetarian’ to have a socially acceptable reason for eating less. On closer examination, so-called ‘vegetarians’ in these studies actually continue to eat chicken and/or fish. A recent study looked at women attending the College of William and Mary and asked them to self-identify as vegetarian (vegan, lacto-vegetarian, lacto-ovo vegetarian), pesco-vegetarian (eats fish), semi-vegetarian (does not eat red meat), flexitarian (eats chicken and fish, occasionally eats red meat), or non-vegetarian. Subjects were asked about specific foods, and group assignment was corrected as necessary. For instance, someone self-identifying as vegetarian who ate fish would be moved to the pesco-vegetarian group. Subjects also answered questions about their motivations and their personality traits. Vegetarians and pesco-vegetarians were more open to new experiences and less afraid of new foods than were non-vegetarians. Restraint (the degree to which someone avoids eating to lose or maintain weight) was similar in vegetarians and non-vegetarians and higher in semi-vegetarians and flexitarians. Food choices of these groups were primarily motivated by weight control; vegetarians and pesco-vegetarians reported that their motivations were mainly ethical. This focus on weight control in semi-vegetarian and flexitarians raises concerns about a possible higher risk for eating disorders.

A recent study of Seventh-day Adventists examined the effect of vegetarian diets on the development of diabetes. The study surveyed more than 41,000 Black and non-Black Adventists in various regions of the United States about their eating and lifestyle habits, medication history, and physical activity. Two years later, study participants were contacted, and those who had developed diabetes were identified. Vegans, lacto-ovo vegetarians, and low meat-eaters (those who ate red meat and poultry less than once a week) were less likely to develop diabetes than were study participants who ate meat more than once a week. The risk of diabetes in those eating fish (but not eating other meat) was not significantly different from that of non-vegetarians. When subjects were examined by ethnicity, vegan, vegetarian, and low-meat diets decreased the risk of diabetes among non-Blacks; only vegan and vegetarian diets reduced the risk of a diabetes diagnosis among Blacks. This study indicates that a vegetarian diet may aid in the prevention of diabetes even among a population already practicing more healthful behaviors. Additionally, this study suggests that vegetarian diets have the potential to help ease the diabetes epidemic.

Many people who do not use dairy products use soy-milk. Fortified soymilk provides calcium, protein, and vitamin D — nutrients that are needed for healthy bones. Furthermore, the isoflavones found in soy may offer some protection from osteoporosis. Researchers from Loma Linda University studied more than 300 post-menopausal women. The women were asked about their diet, and measurements of bone health were made. Women who drank soymilk at least once a day (approximately 1.3 cups of soymilk daily) had a 56 percent lower risk of osteoporosis than did women who did not drink soymilk. (We do not know if the soymilk was fortified.) Similarly, women who used dairy products at least once a day had an almost identical reduction in risk of osteoporosis. These results of this small study suggest that regular use of soymilk can reduce risk of osteoporosis in women.

Our bodies produce vitamin D following sunlight exposure. Melanin, a skin pigment, reduces vitamin D production so that people with darker skin require more sunlight exposure to produce adequate vitamin D than those with lighter skin. A British study examined vitamin D production in people of South Asian (Indian, Pakistani, and Bangladeshi) ancestry. Study subjects were exposed to simulated summer sunlight equivalent to what they would receive by being outside for 30 minutes three times a week for six weeks in the summer wearing a T-shirt and knee-length shorts. This amount of sunlight exposure was not sufficient to achieve adequate vitamin D status in the study subjects. Subjects also had a low dietary vitamin D intake. The results of this study suggest that recommendations for sunlight exposure for dark-skinned South Asian adults might be as much as four times higher than those for fairer skin types and that food or supplemental vitamin D may be needed to meet vitamin D needs.

A traditional method for supporting people who are trying to lose weight is a combination of group classes and individual sessions. This method can be successful but is very labor-intensive and costly, and it is difficult for many people in terms of scheduling. What if, instead of face-to-face meetings, people enrolled in a weight loss program could get support from phone calls, e-mails, and the Internet? Researchers at The Johns Hopkins University tested this idea. Study participants, all of whom were obese, were enrolled in the study for a two-year period with a goal of losing 5 percent of their weight in six months and maintaining that weight loss for the remaining 18 months. They were randomly assigned to one of three groups. One group received support remotely by telephone, e-mail, and a study website. Another received in-person support along with the remote support. The third group was self-directed and did not receive support. After two years, both groups receiving support had lost an average of more than 10 pounds while the group not receiving support had lost an average of less than two pounds. Close to 40 percent of participants receiving support, whether remotely or in person, had achieved the goal weight loss of 5 percent. These results suggest that weight loss programs that provide support through phone calls and e-mail can be as effective as programs providing in-person support. Remote support offers greater scheduling flexibility and may cost less than in-person support.