Researchers at Roswell Park Cancer Institute (RPCI) evaluated myeloperoxidase (MPO), a major enzyme involved in generating ROS. The results, reported in the October 15 issue of Cancer Research, indicate that a specific type of MPO gene appears to reduce breast cancer risk in women who consumed higher amounts of fruits and vegetables, and that this reduction was most pronounced in premenopausal women.

Jiyoung Ahn, MS, RD, and Christine Ambrosone, PhD, Division of Cancer Prevention and Population Sciences, evaluated this hypothesis in a population-based, case-control study of 1,037 women with breast cancer and 1,086 healthy subjects in Nassau and Suffolk Counties, New York. The study was originally conducted by Marilie Gammon, PhD and colleagues from the University of North Carolina.

A specific type of MPO gene was present in 38 and 41 percent of breast cancer cases and population-based controls respectively. Analysis of data found women with this gene type who followed a diet high in fruits and vegetables (more than four servings per day) had a 25 percent lower risk of developing breast cancer. Women with this gene type who ate fewer fruits and vegetables had no risk reduction. Furthermore, when the data was analyzed by menopausal state, premenopausal women who followed diets high in fruits and vegetables had a 60 percent reduction in their risk of breast cancer.

This study adds to the growing body of evidence on the importance of diet, said Ms. Ahn. While we can not control our DNA, this study demonstrates women can effectively modify their risk of breast cancer by eating a diet high in fruits and vegetables.

This is the first paper to examine the role of specific MPO genes and breast cancer risk, noted Dr. Ambrosone. These findings are significant because they may be helpful in the development of new breast cancer prevention strategies.

roswellpark

Calorie restriction also did not result in improved performance on a fear-conditioning task. When a tone is matched with an electric shock, young mice eventually learn to "freeze" when they hear the tone. Old mice, regardless of diet, were much worse at this. In fact, the researchers noticed a trend that suggests mice on calorie restriction diets were even worse than old mice on normal diets. The researchers are not sure, though, whether this poor performance is a sign of learning deficits or of hearing problems that often develop in older mice.

"It's interesting to me that calorie restriction does not seem to reverse age-related cognitive impairments," says David Wozniak, Ph.D., research associate professor of psychiatry, who supervised the behavioral studies. "We need to do bigger, more extensive studies to fully understand these findings, but the bottom line is that you don't get uniformly positive results from calorie restriction. I don't think anyone has really stressed this point before, particularly with regard to the lack of effects on cognition."

In addition to validating these findings in larger groups of mice, the team also is exploring the possibility that adjusting other dietary factors may enhance and add to the calorie restriction diet's benefits. The researchers also have begun testing the protective effects of potent antioxidants on aging mice fed normal diets to see whether they too can prevent or reverse some of the effects of aging.

"We believe sensitive signaling pathways that are particularly important in the brain are disrupted by high levels of free radicals and that these disruptions may explain why, under normal circumstances, brain function declines over time," Dugan says. "Fortunately, it would be much easier to reverse a misregulation in signaling than it would to reverse cell damage."

medinfo.wustl/