Recently published in the International Journal of Environmental Research and Public Health were the results of the largest to-date meta-analysis of 8 cohort studies examining the relationship between dietary change and mortality following a diagnosis of invasive breast cancer. Previously published data suggest that most women do not substantially change eating patterns following a diagnosis; for example, 72% of postmenopausal women in the Women’s Health Initiative had a relatively stable diet following diagnosis, while 19% and 9% increased or decreased their diet quality, per the Healthy Eating Index (HEI). Yet clear and specific dietary guidelines for breast cancer survivors are lacking, and this meta-analysis was conducted to find any effect of diet quality scores on breast cancer-specific or all-cause mortality, with the goal of shaping such guidelines.
The results indicated that an increase in dietary quality following diagnosis could reduce the risk of all-cause mortality by 21% and breast cancer mortality by 15%. Among the diet quality indices reviewed in the meta-analysis, the DASH (Dietary Approach to Stop Hypertension) and CHFP (Chinese Food Pagoda guidelines) were associated with the greatest reduction in breast cancer mortality (HR of 0.79 and 0.64 when comparing the highest vs. lowest diet quality of DASH and CHFP, respectively). In addition, a post-diagnosis increase in the HEI and Mediterranean Diet scores (along with DASH and CHFP) was associated with all-cause mortality reductions. Specific benefits were also identified; for example, there may be a greater benefit in older women, those with a higher BMI, and ER-positive tumors.