Breastfeeding is widely associated with health benefits for mothers and babies, but its protective effect against breast cancer is not universal. A recent study led by researchers from The Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai explored this phenomenon. Published in Nature Communications, the study focused on mice, which also show varied susceptibility to breast cancer despite lactation.
The research revealed that the protective response to breastfeeding may depend on mitochondrial variations. “In mice with specific types of mitochondria, the researchers found, lactation allowed a certain group of cells similar to those found in postpartum breast cancer in humans to expand and grow,” explained Edmund Jenkins, PhD, Assistant Professor of Medicine (Hematology and Medical Oncology) at Mount Sinai.
Senior author Doris Germain, PhD, highlighted that breastfeeding’s effectiveness in reducing breast cancer risk varies based on individual metabolism: “We’ve always thought that breastfeeding is good for all women when it comes to lowering breast cancer risk,” she said. “But our study shows that it really depends on a woman’s metabolism and how her body responds to lactation at the cellular level.”
A promising aspect of the study was discovering that a natural dietary supplement could alter harmful responses during breastfeeding into protective ones. Mrittika Chattopadhyay, PhD, first author and Assistant Professor of Medicine (Hematology and Medical Oncology) at Mount Sinai noted: “Our research raises the possibility that one day, doctors might be able to identify women whose breastfeeding response puts them at risk and then offer them a simple, natural dietary intervention to change that.”
The team plans further research involving human breast milk metabolites and potential dietary interventions post-lactation. The National Institutes of Health funded this research.
