Prospective study suggests that consumption of soy foods, or soy protein or soy isoflavones may reduce the risk of colorectal cancer in postmenopausal women
Researchers at Vanderbilt University School of Medicine in Nashville note that soy and some of its constituents such as isoflavones have been shown to inhibit cancer in experimental studies. Data from epidemiologic studies linking usual soy food intake with colorectal cancer are limited and inconsistent. They prospectively examined 68,412 women aged 40–70 years and free of cancer and diabetes at enrollment. Usual soy food intake was assessed at baseline and reassessed during the first follow-up period.
During a mean follow-up of 6.4 y, 321 colorectal cancer cases were identified. After adjustment for potential confounding factors, total soy food intake was inversely associated with colorectal cancer risk. Each one ounce increase in daily soy food intake was associated with an 8% reduction in colon cancer risk. Women in the highest tertile of intake had a 33% decreased risk o compared with those in the lowest tertile. This inverse association was primarily confined to postmenopausal women. Similar results were also found for intakes of soy protein and isoflavones. The study is published in the November 2nd, 2008 issue of the American Journal of Clinical Nutrition.