Healthful plant-based diet helps fight aggressive breast cancer

Women who follow a healthful plant-based diet have a lower risk of developing breast cancer, especially aggressive tumours, a recent study suggests.

The study followed 76,690 women from the Nurses' Health Study (NHS, 1984–2016) and 93,295 women from the NHSII (1991–2017). Researchers used previously developed indices to evaluate adherence to an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI).

Over 4,841,083 person-years of follow-up, a total of 12,482 incident cases of invasive breast cancer were documented.

Multivariable Cox proportional hazards models showed that greater adherence to PDI was associated with a modest reduction in the risk of breast cancer (quartile 5 vs 1: hazard ratio [HR], 0.89, 95 percent confidence interval [CI], 0.84–0.95). The same was noted for hPDI (quartile 5 vs 1: HR, 0.89, 95 percent CI, 0.83–0.94).

There was a significant heterogeneity by oestrogen receptor (ER) status. Specifically, the beneficial effect of hPDI on the risk of breast cancer was strongly observed for ER-negative tumours (quartile 5 vs 1 of adherence to hPDI: HR, 0.77, 95 percent CI, 0.65–0.90; p_trend<0.01). There also was an inverse association between extreme quintiles of healthy plant foods and ER-negative breast cancer (HR, 0.74, 95 percent CI, 0.61–0.88; p_trend<0.01).

Plant-based diets are known to help fight various diseases, including type 2 diabetes, cardiovascular disease, and other cardiometabolic risk factors. The present data provide evidence of a relationship between hPDI and the risk of total and subtype-specific breast cancer.