Plasma sphingomyelins and carnitine esters of infants consuming whole goat or cow milk-based infant formulas or human milk.

BACKGROUND: Infant formulas are typically manufactured using skimmed milk, whey proteins, and vegetable oils, which excludes milk fat globule membranes (MFGM). MFGM contains polar lipids including sphingomyelin (SM).

OBJECTIVE: Comparison of infant plasma SM and acylcarnitine species between infants who are breastfed or receiving infant formulas with different fat sources.

METHODS: In this explorative study we focused on SM and acylcarnitine species concentrations measured in plasma samples from the TIGGA study (ACTRN12608000047392), where infants were randomized to receive either a cow milk-based infant formula (CIF) with vegetable oils only or a goat milk-based infant formula (GIF) with a goat milk fat (including MFGM) and plant oil mixture at least up to the age of 4 months. Breastfed infants were followed as a reference group. Using tandem mass spectrometry, SM species in the study formulas and SM and acylcarnitine species in plasma samples collected at the age of four months were analyzed.

RESULTS: Total SM concentrations (around 42 μmol/L) and patterns of SM species were similar in both formulas. The total plasma SM concentrations were not different between the formula groups, but were 15 % (CIF) and 21% (GIF) lower in the formula groups than in the breast fed group. Between the formula groups, differences in SM species were statistically significant but small. Total carnitine and major (acyl) carnitine species were not different between the groups.

CONCLUSIONS: The higher total SM concentration in breastfed than in formula-fed infants might be related to a higher SM content in human milk, differences in cholesterol metabolism, dietary fatty acid intake or other factors not yet identified. SM and acylcarnitine species composition in plasma is not closely related to the formula fatty acid composition.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED: ACTRN12608000047392 https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=82514&isReview=true.