The influence of dietary palmitic acid triacylglyceride position on the fatty acid, calcium and magnesium contents of at term newborn faeces

The distribution of long-chain saturated fatty acids in triglycerides is different in infant formulas to that in human milk. In human milk, palmitic acid is predominantly esterified in the sn-2 position (β-position) of the triglycerides, whereas in infant formulas, it is esterified mainly in the sn-1,3 positions (α,α′-positions). The specific distribution of the fatty acids in the triglyceride plays a key role in lipid digestion and absorption. We studied fatty-acid, calcium and magnesium composition in the faeces of three groups of at term newborn infants fed different diets: Group A ( n=12) was fed from birth to 2 months with human milk (66% palmitic acid in β-position), Group B ( n=12) was fed with formula α (19% palmitic acid esterified in β-position) for 2 months, and Group C ( n=12) was fed with formula α during the first month and with formula β (44.5% palmitic acid in β-position) during the second month. Samples were taken at the end of the first month ( t 0) and at the end of the second month ( t 1). Groups A and C presented significantly lower contents of palmitic acid in faeces at t 1 than at t 0, whereas in Group B, amounts remained similar. Faecal calcium in Groups A and C decreased in the second month ( t 1), although the fall was no statistically significant. In Group B, calcium amounts showed no change. We found that infant formula β when compared with infant formula α reduced significantly the contents of total fatty acids and palmitic acid in faeces. We conclude that palmitic acid in β-position is, therefore, beneficial for term infants.