RESUMO
OBJECTIVES: Palmitic acid (PA) constitutes 17% to 25% of the human milk fatty acids, and ~70% is esterified in the sn-2 position of triglycerides (ß-palmitate). In the sn-2 position, PA is not hydrolyzed and thus is efficiently absorbed. The PA in palm oils, commonly used in infant formulas, is esterified in the sn-1 and sn-3 positions. In these positions, PA is hydrolyzed and forms poorly absorbed calcium complexes. The present study assessed whether high ß-palmitate in infant formulas affects the intestinal flora. METHODS: Thirty-six term infants were enrolled: 14 breast-fed (BF group) and 22 formula-fed infants who were randomly assigned to receive formula containing high ß-palmitate (HBP group, n=14), or low ß-palmitate (LBP group, n=8), where 44% and 14% of the PA was ß-palmitate, respectively. The total amount of PA in the formulas was 19% and 22% in the LBP and HBP groups, respectively. Neither formula contained pre- or probiotics. Stool samples were collected at enrollment and at 6 weeks for the quantification of bacteria. RESULTS: At 6 weeks, the HBP and BF groups had higher Lactobacillus and bifidobacteria counts than the LBP group (P<0.01). The Lactobacillus counts at 6 weeks were not significantly different between the HBP and BF groups. Lactobacillus counts were 1.2×10¹°, 1.2×10¹¹, and 5.6×10¹° CFU/g for LBP, HBP, and BF groups, respectively. Bifidobacteria counts were 5.1×109, 1.2×10¹¹, and 3.9×10¹° CFU/g for LBP, HBP, and BF groups, respectively. CONCLUSIONS: HBP formula beneficially affected infant gut microbiota by increasing the Lactobacillus and bifidobacteria counts in fecal stools.