February 7, 2006
Contact: Tom Capezzuto
NEWARK—Postmenopausal women who adhered to a low-fat diet did not significantly reduce the incidence of breast cancer, heart disease, or risk of colorectal cancer, says a researcher at the University of Medicine and Dentistry of New Jersey, who was a principal investigator in the nationwide study conducted by the National Institutes of Health.
The results of the largest national clinical trial of low-fat diet are reported in three papers published in the February 8 edition of the Journal of the American Medical Association.
Among the 48,835 women between the ages of 50 and 79 who participated in the NIH-sponsored trial between 1993 and 2005, there were no significant differences in the rates of colorectal cancer, heart disease or stroke
between the group who maintained a low-fat dietary plan and those who did not, said Dr. Norman L. Lasser, a preventive cardiologist and director of the Women's Health Initiative study at the UMDNJ-New Jersey Medical School in Newark.
"We found that the postmenopausal women in the study who reduced their total fat intake had only about a 9 percent lower risk of contracting breast cancer than did women who made no dietary changes," Dr. Lasser said. "The difference was not large enough to be statistically significant, meaning it could have been attributable to chance."
The study was funded by the National Heart, Lung and Blood Institute, an NIH unit responsible for organizing and overseeing research associated with the Women's Health Initiative study. It was conducted at 40 sites in the United
States, including the UMDNJ-New Jersey Medical School. A total of 1,800 women registered in the Newark-based study led by Dr. Lasser; women were followed for an average of 8.1 years.
"This study does not lead us to alter our recommendations on disease prevention," said Dr. Lasser. "Women should continue regular mammograms, colorectal cancer screenings and maintain low-fat diets."
The study diet focused on reducing total fat and, unlike diets used to reduce heart disease risk, did not differentiate between the "good fats," found in fish, nuts and vegetable oils, and "bad fats," like saturated fat and trans fat found in processed foods, meats and some dairy products.
The study theory tested the widely-held belief that the reduction of total fat would reduce risks of breast or colorectal cancers. For heart disease, the reduction in total fat was expected to include a decrease in saturated
fats, which are known to increase the risk of heart disease. However, reducing total fat intake did not go far enough to have an impact on heart disease risk, since the reduction in bad cholesterol was small.
By the end of the first year, Dr. Lasser noted that the low-fat diet group reduced their average total fat intakes to 24 percent of calories from fat, but did not reach the study's goal of 20 percent. The comparison group averaged 35 percent of calories from fat at year one. The low-fat diet group also increased their consumption of vegetables, fruits and grains.
To arrange an interview with Dr. Lasser, call Tom Capezzuto at (973) 972-3000.