Researchers Find Flavonoid-Rich Foods May Protect Against Inherited Breast Cancer Risk

A higher intake of flavonoid-rich foods may be linked to a lower risk of breast cancer, according to a new study published in npj Breast Cancer.

Researchers analyzed data from 93,271 women in the UK Biobank to examine whether the Flavodiet Score (FDS)—a measure of flavonoid-rich food consumption—was associated with breast cancer risk. Participants were followed for a median of 11.8 years, during which 3,110 women developed breast cancer.

The Flavodiet Score included 10 flavonoid-rich foods, such as tea, apples, oranges, grapes, berries, onions, sweet peppers, dark chocolate, grapefruit, and red wine. Researchers also performed additional analyses excluding red wine, and the results remained similar, indicating the association was not driven by alcohol intake.

Women in the highest FDS category had a 15% lower risk of developing breast cancer compared with those in the lowest category. Higher intakes of flavanones and proanthocyanidins—two flavonoid subclasses—were also linked to a reduced risk. Among individual foods, oranges and apples showed the strongest protective associations.

The study also examined genetic susceptibility using a polygenic risk score based on 168 breast cancer-related genetic variants. Women with a high genetic risk and a low flavonoid intake had the greatest likelihood of developing breast cancer. In contrast, those with high flavonoid intake had a lower risk, even among individuals with elevated genetic susceptibility, although no significant interaction between diet and genetics was identified.

Researchers noted that participants with higher flavonoid intake generally had healthier lifestyles, including greater physical activity and lower body weight. Because the study was observational, it cannot establish cause and effect. The authors say further research in more diverse populations and clinical trials is needed to confirm whether flavonoid-rich diets can help reduce breast cancer risk.

REFERENCE: Yang R, Xu YL, Wang Y, et al. (2026). Flavonoid-rich foods, genetic risk, and female breast cancer risk: a prospective cohort study. npj Breast Cancer. DOI: 10.1038/s41523-026-00989-y, https://www.nature.com/articles/s41523-026-00989-y