Branched-chain fatty acids in the neonatal gut and estimated dietary intake in infancy and adulthood

Abstract

Branched-chain fatty acids (BCFA) are primarily saturated fatty acids (FA) with a methyl branch, usually near the terminal methyl group. BCFA are abundant in bacteria, skin, and vernix caseosa but have seldom been studied with respect to human nutrition. They are constituents of the term newborn infant gut lumen, being swallowed as vernix particulate components of amniotic fluid in the last trimester of normal pregnancy. We recently showed that BCFA protect against necrotizing enterocolitis (NEC) in the rat pup model. Dietary BCFA at levels similar to those found in human vernix reduced NEC incidence by more than 50%, increased the abundance of BCFA-containing bacteria, and increased the expression of ileal anti-inflammatory IL-10. The few published reports of BCFA in human milk enable an estimate that breastfed infants consume 19 mg BCFA per 100 ml milk. Dietary BCFA consumption from milk fat and other ruminant products, the main sources of dietary BCFA, is more than 400 mg BCFA per day in adult Americans. This estimate exceeds by severalfold the average dietary intake of bioactive FA, such as docosahexaenoic acid. BCFA are bioactive, abundant but neglected components of the human food supply.

Figure 1

A. The proportions of animals that were healthy (white) and ill with NEC (black) in each treatment group: DF (Dam Fed; no sick animals), Control (Formula Fed, no BCFA; 17 of 31 animals were sick), BCFA (Formula Fed, 20%,w/w BCFA; 5 of 24 animals were sick). B. NEC incidence in rat pups in all experimental groups. NEC was significantly lower in the BCFA group compared to the Control group *p<0.05 Control vs. BCFA.

Figure 2

A. The relative abundance (%; mean ± SEM) of Bacillus subtilis and Pseudomonas aeruginosa in the treatment groups: DF (Dam Fed), Control (Formula Fed, no BCFA), BCFA (Formula Fed, 20%,w/w BCFA). B. Bacillus subtilis in healthy animals and in animals with NEC. Data not marked by the same symbol are significantly different *(p<0.05).