Effects of low-fat and/or high fruit-and-vegetable diets on plasma levels of 8-isoprostane-F2α in the nutrition and breast health study

Dietary patterns that involve both a decrease in fat and an increase in fruit and vegetable (FV) intake may decrease cancer risks. In this study, a total of 122 premenopausal women with a family history of breast cancer were randomized into one of four diets for 12 mo: nonintervention, low fat (15% of energy from fat), high-FV (9 servings/d), and combination low-fat/high-FV. Fasting blood samples were obtained at baseline and after 3, 6, and 12 mo. Levels of 8-isoprostane-F-2alpha in plasma were determined by immunoassay kits. Statistical analyses indicated that levels of 8-isoprostane-F-2alpha decreased significantly with time in the low-fat arm, which is the only intervention that resulted in weight loss; there were no significant changes in the other three diet arms. It is unlikely that this is due to changes in levels of blood lipids because there was little change over time in plasma total cholesterol, high-density lipoprotein, low-density lipoprotein (LDL), or triglyceride levels in an diet arm, although mean LDL did decrease slightly in women who reduced fat intake after adjustment for change in body mass index (BMI). Levels of baseline 8-isoprostane-F-2alpha were significantly higher in obese women than in over weight or normal weight women, and change in BMI was significantly correlated with change in 8-isoprostane-F-2alpha levels. These results indicate that low-fat diets or high-FV diets are unlikely to affect plasma levels of 8-isoprostane-F-2alpha in healthy, premenopausal women who do not lose weight during dietary change.