Human milk fat substitutes: Past achievements and current trends.

The first commercial infant formula, invented in 1867, contained lipids mainly from cow's milk. We now know that human milk fat differs from the milk fat of other mammals and even more from vegetable oils. Human milk fat is one of the most complex natural lipid mixtures with a unique fatty acid composition, distribution, and numerous complex lipids. Therefore, to mimic human milk fat, human milk fat substitutes (HMFSs) have been produced through the enzymatic/chemical modification of natural lipids. Researchers have become increasingly interested in use of HMFSs as functional lipids due to their nutritional effects on the growth and development of formula-fed infants. This paper discusses the history and recent advances in HMFSs. A comprehensive summary of the composition of human milk fat (fatty acids, sn-2 fatty acids, triacylglycerols, and complex lipids) and its structure (human milk fat globules), as well as the changes during the lactation period. Nutritional bases, preparation methods, and applications of HMFSs (long-chain polyunsaturated fatty acids, sn-2 palmitate, medium-chain triacylglycerols, and milk fat globule membrane supplements) have been reviewed. Legislation relating to the fat fraction of infant formulae are also presented in this paper.