Differences in vitamin E and C profile between infant formula and human milk and relative susceptibility to lipid oxidation.

The vitamin E isoforms and vitamin (vit) C content of infant formulas were compared to human milk and related to relative susceptibilities to lipid peroxidation. We report that a highly distinct vitamin E and C profile exists between formula and human milk. Whileα-tocopherol (α-Toc) is the dominant vit E isoform in human milk, formula contains a substantial amount of α-Toc and δ-Toc that was greater than the level found in human milk (12- and 32-fold, respectively). Vitamin C was also two- fold higher in infant formula compared to human milk. Despite the higher vitamin E and C content, we also observed higher rates of lipid oxidation in the formula when compared to human milk. Storing human milk for one day at refrigeration temperatures did not produce hexanal in human milk, but this storage resulted in an increase in hexanal in formulas. We conclude that the higher concentrations of γ-Toc and δ-Toc in infant formulas did not provide similar protection from lipid oxidation as human milk. We also observed that vit C content was reduced during storage in both infant formula and human milk, which did not occur with the Toc isoforms.