The Power of Human Milk Oligosaccharides (HMOs): Nature’s Unsung Hero in Infant Nutrition and Beyond Human milk has long been recognized as the gold standard in infant nutrition, but one of its most fascinating and powerful components—Human Milk Oligosaccharides (HMOs)—is only now gaining the recognition it deserves. HMOs are the third most abundant solid component in human milk, following lactose and fat, and they hold the key to many of the immune-boosting and developmental advantages breastfed infants receive.