IN FAT~R:The fat component that mimics the special fat structure of human milk

摘要

Human milk is considered the gold standard in infant nutrition. The World Health Organization (WHO) recommends exclusive breastfeeding up to 6 months of age, with continued breastfeeding along with appropriate complementary foods up to 2 years of ageor beyond. Human breast milk provides the optimal nutrition for infants. Designed to provide perfectly balanced nutrition, human breast milk naturally meets the needs of growing infants in the first months of life. The fat in human milk, and in most infant formulas, provides about 50% of the energy newborns require for proper development and growth. More than 98% of this fat is in the form of triglycerides, which contain saturated and unsaturated fatty acids esterified to a glycerol backbone. Triglyceride synthesis occurs in the mammary glands, and the fatty acids are specifically positioned at certain locations called sn-1, sn-2 and sn-3 on the glycerol backbone. Two fatty acids are particularly abundant in human milk. Palmitic acid (C16:0) is the main saturated fatty acid, comprising 17-25% of the fatty acids in mature human milk, while oleic acid is the main unsaturated fatty acid (C18:1), comprising around 28-30% of all fatty acids in human milk. A report from the 1960s suggested that human milk triglycerides have a unique structure, where the palmitic acid is attached primarily (70-75%) to the sn-2 position of the triglyceride, suggesting preferential positioning of palmitic acid at the sn-2 position. This is surprising, since this very specificpositioning differs from that in other human tissue and plasma lipids. This special structure is also different from the structure of vegetable oils that are common in human diets and in the fat blends used in the manufacture of infant formula. Additionally, researchers found that this fatty acid position is conserved in all women, regardless of their ethnic origin or nutrition, suggesting that this special structure may also be beneficial for infants.