Early Diet May Determine Risk.

• Position: Brief Article

Increasing evidence reveals that fetal and childhood diets may have a greater impact on lifetime breast cancer risk than diets during adulthood, says Leena Hilakivi-Clarke of the Lombardi Cancer Center at Georgetown University, Washington, D.C. Previous research has linked diets that raise levels of estrogen in the blood with greater risk for breast cancer. However, Hilakivi-Clarke and her colleagues suggest that the link between estrogen and cancer risk is more complex than previously thought, and that a new variable--time of life--seems to play an all-important role.

"At certain stages of a woman's life, particularly in the womb and after menopause, diets that introduce high estrogen levels do indeed seem to increase her risk of getting breast cancer. During reproductive years, however, high estrogen levels show no effect at all," Hilakivi-Clarke explains. Moreover, laboratory and human studies indicate that at still another time--childhood--high estrogen levels seem to play a powerful protective role against breast cancer. "These are surprising results, because most of the scientific literature to date suggests that high-fat diets tend to raise breast cancer risk, not lower it. But it's important to remember that research has only begun to study the importance of childhood diets on cancer risk."

Hilakivi-Clarke cautions that many variables remain to be studied before responsible dietary recommendations can be made. "We know that Asian women, who consume high amounts of soy, have very low rates of breast...