A study published online Feb. 16 in the European Journal of Nutrition by scholars from China and the United States suggests that soluble dietary fiber intake in premenopausal women is associated with a significantly lower risk of estrogen receptor (ER)-negative breast cancer. The results of this study need to be confirmed by a larger sample size study. The study is a case-control study of women with breast cancer conducted in Connecticut, USA. A total of 557 cases of incident breast cancer and 536 age-matched controls were enrolled. The investigators used a semi-quantitative food frequency questionnaire to collect dietary information through in-person interviews and translate it into nutrient intake. Results showed that among premenopausal women, a high intake of soluble dietary fiber (intake quartile: maximum vs. minimum) was associated with a reduced risk of breast cancer; when further qualified as ER-negative for breast cancer, the corrected breast cancer risk ratio (OR) for those in the largest quartile of soluble dietary fiber intake was 0.15 (p=0.02). In postmenopausal women, the study did not observe a reduction in breast cancer risk with soluble or insoluble fiber intake in ER-positive or ER-negative patients.