Recently various attempts have been made aiming at bringing infant formula content closer to that of human milk. Palmitic-acid (PA) constitutes 17-25% of human milk fatty acids, and is mainly (~70%) esterified to the middle (sn-2) position of the triglycerides (beta-palmitate). PA in vegetable oils, commonly used for infant formulas, is esterified to the sn-1 and sn-3 positions. Our aim was to explore the effect of beta-palmitate in formula on composition of the intestinal microbiota of infants.
Thirty-six infants were included: 22 formula-fed and 14 breastfed (BF group). Formula-fed infants were randomly assigned to receive formula-containing beta-palmitate (HBP group, n=14), or vegetable oil (LBP group, n=8). Stool samples were collected at enrollment and after 6 weeks, and microbial and metagenomic analyses were applied to gain comprehensive information about the microbial communities in these samples. Bacteria were grown on selective media for counting, and total microbial DNA, purified from each stool sample, was used for amplification of rDNA for 454 pyrosequencing. At 6 weeks the HBP and the BF groups demonstrated significantly higher counts of Lactobacilli and Bifidobacteria compared with the infants in the LBP group (p<0.01). Clostridia decreased in the HBP group while increased in the LBP group, but this change was not statistically significant. The sequencing results did not always correlate with the results of plate-counting. No significant differences were observed in overall diversity of microorganisms in the three groups, but several Bifidobacteria and Lactobacillus species unique to HBP and BF were identified. This pilot study demonstrates that beta-palmitate may provide beneficial effects on gut microflora of formula fed infants.
