News from the Fourth International Congress on Vegetarian Nutrition.

In August 2002, The Fourth International Congress on Vegetarian Nutrition was held in Loma Linda, CA. More than 400 people from over 40 different countries attended this congress to learn about recent research on vegetarianism. The proceedings of this congress were published in a 170-page supplement to the American Journal of Clinical Nutrition. Here are a few reports that seemed especially interesting:

Are Some Vegetarians Really Meat-Free? Or Do They Just Say They Are?

Researchers from Loma Linda University used data from a large survey of people in the United States conducted by the USDA. One survey question asked if respondents considered themselves to be vegetarian. Of the 13,313 respondents, 334 considered themselves vegetarians. Respondents kept a record of what they ate for two days. When these records were examined, only 120 people who defined themselves as vegetarian actually did not eat meat, fish, or poultry. The diets of those who did not eat meat were different, nutritionally speaking, from those who did eat meat. This study shows how important it is for researchers and dietitians to clarify what someone means when they say they are vegetarian.

Haddad EH, Tanzman JS. 2003. What do vegetarians in the United States eat? Am J Clin Nutr 78 (suppl):626S-32S.

Iron and Zinc Rarely a Problem for Western Vegetarians

Janet Hunt, a noted researcher on iron and zinc, concluded that adverse health effects from lower iron and zinc absorption in vegetarians living in developed countries have not been demonstrated. She recommended monitoring iron status of vegetarian children and premenopausal women and prescribing iron supplements only when iron deficiency is seen.

Hunt JR. 2003. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr 78 (suppl):633S-39S.

Achieving Optimal Fatty Acid Status

Vegetarian diets are often low in some key fatty acids like DHA, EPA, and alpha-linolenic acid. A session at the congress presented guidelines for achieving optimal fatty acid status in vegetarians. These include eating a variety of whole plant foods; getting most fat from whole foods like olives, nuts, seeds, and soy foods; selecting olive, canola, and nut oils for cooking; limiting intake of processed foods and deep-fried foods; choosing foods rich in alpha-linolenic acid like flaxseed, flaxseed oil, hempseed oil, walnuts, canola oil, and soy products; and considering use of a DHA supplement derived from microalgae.

Davis BC, Kris-Etherton PM. 2003. Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications. Am J Clin Nutr 78 (suppl):640S-46S.

Environmental Impact of Various Diets

One symposium focused on the ecologic and environmental impacts of different diets. Claus Leitzmann, a German researcher, concluded that "vegetarian diets are well suited to protect the environment, to reduce pollution, and to minimize global climate changes." He recommended using organically grown, regionally produced, in-season food. (1) Two researchers from Cornell University analyzed the use of land and energy resources needed for a meat-based diet compared to a lacto-ovo vegetarian diet. The meat-based diet required more energy, land, and water resources. (2) Researchers from The Netherlands and the United States also found an environmental advantage to vegetarian diets. They report, however, that a vegetarian diet consisting mainly of exotic foods transported long distances by plane, frozen vegetables, or vegetables grown in fossil fuel-heated greenhouses may lead to a greater environmental burden than that of locally produced organic meat. (3)

(1) Leitzmann C. 2003. Nutrition ecology: the contribution of vegetarian diets. Am J Clin Nutr 78 (suppl): 657S-59S.

(2) Pimentel D, Pimentel M. 2003. Sustainability of meat-based and plant-based diets and the environment. Am J Clin Nutr 78 (suppl):660S-63S.

(3) Reijnders L, Soret S. 2003. Quantification of the environmental impact of different dietary protein choices. Am J Clin Nutr 78 (suppl):664S-68S.