Katie Hinde: Arizona State University

Mother’s milk is more than a food full of essential nutrients and more than a medicine packed with protective immunofactors. Mother’s milk contains maternal signals- hormones- that influence infant metabolism, neurobiology, and behavior. A growing body of evidence demonstrates that hormones from the mother, ingested through milk, bind to receptors within the young. Glucocorticoids in mother’s milk have been associated with offspring temperament, behavior, and cognition in rodents, monkeys, and humans. Among monkeys, glucocorticoids in mother’s milk, predict better cognitive performance and, independent of available milk energy, predict a more Nervous, less Confident temperament in both sons and daughters. Additionally, maternal-origin glucocorticoids in milk predict offspring growth. Taken collectively, emerging results suggest that mothers with fewer somatic resources may be “programming” behaviorally cautious offspring that prioritize growth through hormonal signaling. Glucocorticoids ingested through milk may importantly contribute to the assimilation of available milk energy, development of temperament, and orchestrate, in part, the allocation tradeoffs of maternal milk energy between growth and behavior.