Multidimensional evaluation of the similarity between infant formulas and human milk based on macronutrients, fatty acid composition and positional distribution, and sn-2 palmitoyl triacylglycerols

A multidimensional similarity evaluation was conducted between 12 commercial infant formulas (6 1,3-dioleoyl-2-palmitoylglycerol [OPO]-fortified samples; 6 nonfortified samples) and 205 human milk samples from Hainan Island, China, in this study. The results showed that 12 brands of infant formulas had high similarity scores to human milk at the nutrient composition and energy supply (G_NE > 88), total fatty acid composition (G_FA > 80), and sn-2 palmitoyl triacylglycerol (G_OPO and G_OPL > 82) levels. However, the similarity scores of infant formulas at the sn-2 FA level were generally low (G_{sn-2 FA} < 69). Further analysis showed that, in terms of sn-2 FA levels, arachidonic acid and docosahexaenoic acid were the main reasons for the low similarity score across 12 infant formulas. Furthermore, 4-dimensional multivariate statistical analysis further visually demonstrated that OPO-fortified infant formulas had higher similarities to human milk than nonfortified samples did. In summary, although fortifying OPO can improve the overall similarity between infant formulas and human milk, there are still significant differences in the sn-2 FA between the two. It is suggested that future studies should focus on optimizing the positional distribution of FA (especially arachidonic acid and docosahexaenoic acid) in infant formulas, rather than merely emphasizing their content, so as to achieve a comprehensive and scientific infant formula design.