A recent study has allegedly linked higher red meat intake in early adulthood to an increased breast cancer risk, raising questions about how dietary habits adopted before midlife can affect health outcomes. Maryam Farvid, et al., “Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study,” BMJ, June 2014. In addition to analyzing food questionnaire data from 88,803 premenopausal women ages 26-25 who were enrolled in the Nurses’ Health Study II, researchers with the Harvard School of Public Health documented 2,830 cases of breast cancer during 20 years of follow-up. Based on this data, they concluded that not only were higher intakes of total red meat associated with an increased risk of breast cancer overall, but that “higher intakes of poultry, fish, eggs, legumes, and nuts were not related to breast cancer overall. “

“So far, studies have suggested no significant association between red meat intake and breast cancer,” explains a concurrent BMJ press release. “However, most have been based on diet during midlife and later, and many lines of evidence suggest that some exposures, potentially including dietary factors, may have greater effects on the development of breast cancer during early adulthood.”

To this end, the study’s authors reported that the “each serving per day increase in red meat was associated with a 13% increase in risk of breast cancer,” noting that although “this is relatively small risk” when applied to breast cancer, “the absolute number of excess cases attributable to red meat intake would be substantial, and thus a public health concern.” As a result, the authors suggested that replacing red meat with legumes and poultry during early adulthood per American Cancer Society dietary guidelines could reduce breast cancer risk later in life.