Breast Mammographic Changes Among WomenAdopting a Low-Fat Eating Pattern

Extract

Boyd et al. ( 1 ), in this issue of the Journal, report reductions in the area of mammographically dense tissue among women undertaking a low-fat, high-carbohydrate diet (hereafter, a lowfat eating pattern) in a randomized trial context. The trial involves women in the age range of 30–65 years whose baseline mammographic images showed radiologic densities in at least 50% of the breast area, based on a single craniocaudal view of one randomly selected breast. The women assigned to dietary intervention were taught how to make a major isocaloric dietary change, with a goal of 15%, 20%, and 65% of energy from fat, protein, and carbohydrates, respectively, while the control group consumed a self-selected diet.

The article is based on 817 women (403 in the intervention group and 414 in the control group) from whom follow-up mammographic images were obtained at about 2 years from randomization. Matched baseline and follow-up mammographic images were analyzed in a blinded, computer-assisted fashion to estimate total breast area and total area of dense tissue from each mammographic view. Intervention women experienced a modest, but significantly greater, reduction than control women in both breast area (2.5% in the intervention group and <0.1% in the control group) and area of density (6% in the intervention group and 2.5% in the control group). The difference in total breast area, but not in density area, appeared to be largely attributable to differential weight change (average, 0.3-kg weight loss for intervention women; average, 0.9-kg weight gain for control women). The change in percent of breast area with density did not differ significantly between intervention and control women. The differential reduction in area with density seemed most evident among the 76% of women who were premenopausal at baseline, especially in the subset of 90 women (50 in the intervention group and 40 in the control group) who became postmenopausal during the 2-year follow-up period.