Scientific Update

A Review of Recent Scientific Papers Related to Vegetarianism

School Lunch Update

More than 30 million children participate in the School Lunch Program each day. Meals eaten at school can have considerable impact on a child's health and eating experiences. Since 1991, a massive study of school meal programs has been conducted approximately every 6-7 years. The third U.S.D.A. School Nutrition Dietary Assessment Study (SNDA-III) was conducted in 2004-2005 and involved 398 schools in 36 states. Here are some key findings:

  • Only 6 percent of schools met all of the SNDA-III standards, including those for total calories, fat, sat- urated fat, protein, vitamin A, vitamin C, calcium, and iron.
  • Only 5 percent of menus included whole grain breads other than as part of an entrée, and only 10 percent included legumes.
  • Very few schools (less than 8 percent) offered lunches or breakfasts that met the SNDA-III stan- dard for fiber.
  • No schools offered lunches that met the SNDA-III standard for sodium.
  • Most schools offered lunches that were higher in fat and saturated fat than recommended; 81 per- cent of schools exceeded the standard for fat and 72 percent exceeded the standard for saturated fat. Major sources of fat and saturated fat included hamburgers, chicken patties, pizza, tacos, and whole and 2% cow's milk.
  • Fresh fruit or raw vegetables were not offered on a daily basis in 42 percent of schools. These foods were significantly less common in schools with a higher percentage of low-income students.
  • Less than a third of menus offered orange or dark green vegetables, such as raw carrots and broccoli. Vegetables were much more likely to be starchy vegetables, like corn, French fries, and other potatoes.
  • Approximately half of high school lunch menus included French fries or similar products; 20 percent of elementary school menus included these foods.
  • Elementary school students in schools that offered French fries more than once a week and those in schools offering desserts more than once a week were more likely to be obese.

Although there are definite improvements since SNDA- II, these results paint a fairly dismal picture of the School Lunch Program. Recommendations for improving the program include more whole grains, fresh fruits, dark green and/or orange vegetables, and legumes, as well as more meatless entrées. Improved funding for this program and for programs to educate children about healthy food choices is also recommended.

Gordon AR, Crepinsek MK, Briefel RR, et al. 2009. The Third School Nutrition Dietary Assessment Study: summary and implications. J Am Diet Assoc 109 (Suppl 1):S129-35.

Teens Want More Locally Grown, Organic, Non-Genetically Engineered,and Unprocessed Food

Some adults choose foods that are locally grown, organic, or unprocessed. Have these types of choices also influenced teens and young adults? Researchers surveyed more than 2,500 people aged 15-23 years and asked them how important it was that their food be locally grown, organic, or unprocessed. They were also asked if they were currently a vegetarian. Responses to this question indicated some confusion about what a vegetarian is, with 46 percent of self-described vegetarians eating fish and 25 percent eating chicken.

Of those surveyed, 34 percent felt that it was important for their food to not be genetically engi- neered, while 30 percent valued unprocessed food. Organic food was important for 23 percent of respon- dents, and locally grown food was important for 21 percent. These numbers indicate a strong interest in food with a lower impact on the environment among young adults. Those who more strongly supported these food production practices were more likely to have healthy diets and less likely to eat fast food. In addition, those with an interest in more sustainable food production practices were more likely to be either African-American or Asian, to be from a lower income family, and to be vegetarian. The researchers suggest that adolescents who have greater awareness about the use of pesticides in agriculture and who participate more in food shopping and preparation are more likely to support use of locally grown and organic foods. Furthermore, they suggest that both vegetarians and those who value more sustainable food production are more likely to choose foods that promote both individual and environmental health.

Robinson-O'Brien R, Larson N, Neumark-Sztainer D, et al. 2009. Characteristics and dietary pat- terns of adolescents who value eating locally grown, organic, nongenetically engineered, and nonprocessed food. J Nutr Educ Behav 41:11-18.

Impact of "Modernization" on a Traditional Near-Vegetarian Community

Ten years ago, the Tepehuanos Indians, who live in northern Mexico, followed their traditional diet based on foods that they grew and produced, includ- ing abundant green vegetables, beans, potatoes, breads, and tortillas made from a mixture of roots. They rarely ate meat and generally followed a vegetarian diet. No one was obese, although close to 10 percent of people were overweight. No one surveyed had a specific meta- bolic syndrome or diabetes, and less than 2 percent had high blood pressure.

In 2000, as part of a social assistance program, Western foods were introduced, either free or at very low cost. Local stores featured sugar, pasta, instant soup, cheese, and soft drinks. The Indians were given free food packages that included rice, coffee, sugar, pasta, maize flour, cookies, and junk foods. As a result of these changes, the Indians ate fewer green vegeta- bles, beans, potatoes, and homemade tortillas and ate more meat, cheese, and maize flour tortillas. Six or seven years after the new foods were introduced, 22 percent of those surveyed were either obese or overweight, 10 percent had the metabolic syndrome, and 3.5 percent had high blood pressure. Use of alcohol and cigarettes also had increased. This is clearly an example of what has happened in many traditional cultures where a low-meat, high-vegetable diet has been modified to include many more processed foods, animal products, and soft drinks. The result of this is inevitably an increase in risk factors for diabetes, heart disease, and high blood pressure.

Rodriguez-Moran M, Guerrero-Romero F, Rascon- Pacheco RA, et al. Dietary factors related to the increase of cardiovascular risk factors in traditional Tepehuanos communities from Mexico. A 10 year follow-up study. Nutr Metab Cardiovasc Dis 2009 Jan 16 [Epub ahead of print]

Post-Menopausal Asian Women Who Consumed Soy Had Reduced Risk of Colorectal Cancer

Cancer of the colon and rectum is less common in Asian countries than in Western countries. One possible factor for this difference in disease may be the higher intake of soy products in Asian countries. A large study in Shanghai examined close to 70,000 women aged 40-70 years. The women completed questionnaires measuring their intake of soy foods (soymilk, tofu, dried tofu, fresh soybeans, dry soy beans, and soy sprouts) at the beginning and the end of the study. The number of women who developed colorectal cancer over the approximately 6-year-long study was determined. After adjusting for age, women who ate more soy foods had a reduced risk of colorectal cancer. Every ounce of tofu eaten per day reduced colorectal cancer risk by approximately 8 percent. The reduced risk of cancer was mainly seen in post- menopausal women, where the risk of colorectal cancer was 30 percent lower among women with the highest intakes of soy foods compared with women with the lowest soy foods intake. The soy foods that were studied were fresh soy products, as opposed to fermented products, such as miso and tempeh, or processed foods, like soy burgers. These fresh soy products are typical of the diet of the women in this study. We do not know if the results would have changed if other types of soy products had been used. However, the results of this study suggest that soy food consumption may reduce the risk of colorectal cancer, especially among women after menopause.

Yang G, Shu X-O, Li H, et al. 2009. Prospective cohort study of soy food intake and colorectal cancer risk in women. Am J Clin Nutr 89:577-83