Effect of high sn-2 palmitate infant formula on the excretion of fatty acids, calcium and magnesium in infants

Objective To explore the effect of high sn-2 palmitate infant formula (HPIF) on stool frequency and consistency, fatty acids, calcium and magnesium contents in infants. Methods A prospective, double-blind, randomized, controlled clinical study was conducted including 94 healthy mature infants of single birth and appropriate for gestational age, born from June 2013 to December 2014. All eligible infants were enrolled within 21 days after birth. All the infant formula fed subjects were divided randomly into two groups as standard infant formula (IF) group and high sn-2 palmitate infant formula (HPIF) group. Breast-fed infants were enrolled as control group (BF group). All infants were followed up until 90 days old. The growth indexes and defecation status of the three groups were monitored dynamically. Meanwhile, stool fatty acid profile and mineral contents were also detected. Results There was no significant difference in head circumference, body length and body weight among the three groups at enrollment, 42 days and 90 days old. The stool frequency and mushy stool frequency of HPIF and IF groups were significantly lower than that of BF group at 42 days and 90 days old; formed stool frequency was higher in HPIF and IF groups than in BF group. The fecal palmitic acid level in dry feces was significantly higher in HPIF and IF groups than in BF group [(31.1±9.8), (30.9±10.7) vs. (10.8±8.8)mg/g] at 42 days old. At 90 days old, the fecal palmitic acid level in dry feces was significantly lower in HPIF group than in IF group [(24.3±9.8) vs. (29.9±7.9)mg/mg], while was significantly higher in both infant formula fed groups than in BF group [(8.9±8.4)mg/g]. The fecal calcium level in dry feces of HPIF and IF groups were significantly higher than that of BF group [(38.3±14.0), (38.8±15.5) vs. (21.3±13.7)mg/g] at 42 days old. At 90 days old, the fecal calcium level in dry feces of HPIF group was significantly lower than that of IF group [(31.1 ± 11.2) vs. (45.9 ± 16.5)mg/g, dry stool] and significantly higher than that of BF group [(21.5 ± 9.9)mg/g]. The fecal magnesium level was similar between HPIF and IF groups, and significantly higher than that of BF group at 42 days and 90 days old. The fecal calcium level was positively correlated with the content of fecal palmitic acid among three groups (r=0.43, P<0.01). Conclusions Breast milk is the best food for infants. Compared with standard infant formula, feeding with high sn-2 palmitate infant formula can reduce the fecal excretion of calcium and palmitic acid, making it closer to the level of breast-fed infants. Key words: Infant formula; Fatty acids; Palmitic acid; Calcium; High sn-2 palmitate