On diet and cancer risks.

Dath rates from cancer among Seventh Day Adventists in the Los Angeles area are only about half those of the general population, according to Padmanabhan Nair, a chemist at the Lipid Nutrition Laboratory. Nair, who collaborated with a team of researchers headed by Roland Phillips, who is at Loma Linda (Calif.) University, studied dietary factors that differentiated these Seventh Day Adventists from the general population. Most of the Adventists were teetotalers, the study found, and roughly 70 percent were either strict vegetarians or ovalacto vegetarians, whose diets include milk and eggs.

This vegetarianism contributed to the Adventists' low consumption of fat; Nair says only 25 to 35 percent of their calories were fat-derived, as opposed to 41 percent in the standard U.S. diet. Vegetarianism also contributed to the Adventists' low cholesterol intake; Nair sas the 100 to 150 milligrams they consumed daily was less than half the national average.

Studies have shown that colon-cancer death rates are higher among meat eaters than among ovalacto vegetarians. Data on strict vegetarians also suggest lower rates but are preliminary, Nair says. Fat may be one reason for the lower rates, he says, pointing out that several studies have shown "a close association between both colon- and breast-cancer mortality and the amount of fat consumed."

Spurred in part by these data on Adventists, Nair and his colleagues in Beltsville have begun a series of year-long studies to explore how diets that differ in the proportion of fat-derived calories alter human body chemistry -- such as cholesterol metabolism or hormone cycles -- in ways that might change the risk of cancer.