Associations of low‐carbohydrate diets with breast cancer survival

Abstract

AbstractBackgroundThe objective of this study was to evaluate the role of low‐carbohydrate diets after breast cancer diagnosis in relation to breast cancer–specific and all‐cause mortality.MethodsFor 9621 women with stage I–III breast cancer from two ongoing cohort studies, the Nurses’ Health Study and Nurses’ Health Study II, overall low‐carbohydrate, animal‐rich low‐carbohydrate, and plant‐rich low‐carbohydrate diet scores were calculated by using food frequency questionnaires collected after breast cancer diagnosis.ResultsParticipants were followed up for a median 12.4 years after breast cancer diagnosis. We documented 1269 deaths due to breast cancer and 3850 all‐cause deaths. With the use of Cox proportional hazards regression and after controlling for potential confounding variables, we observed a significantly lower risk of overall mortality among women with breast cancer who had greater adherence to overall low‐carbohydrate diets (hazard ratio for quintile 5 vs. quintile 1 [HRQ5vsQ1], 0.82; 95% CI, 0.74–0.91; ptrend = .0001) and plant‐rich low‐carbohydrate diets (HRQ5vsQ1, 0.73; 95% CI, 0.66–0.82; ptrend < .0001) after breast cancer diagnosis but not animal‐rich low‐carbohydrate diets (HRQ5vsQ1, 0.93; 95% CI, 0.84–1.04; ptrend = .23). However, greater adherence to overall, animal‐rich, or plant‐rich low‐carbohydrate diets was not significantly associated with a lower risk of breast cancer–specific mortality.ConclusionsThis study showed that greater adherence to low‐carbohydrate diets, especially plant‐rich low‐carbohydrate diets, was associated with better overall survival but not breast cancer–specific survival among women with stage I–III breast cancer.