[Effects of infant formula containing palm oil on the nutrient absorption and defecation in infants: a meta-analysis].

OBJECTIVE

To evaluate the effects of infant formula containing palm oil on the nutrient absorption and defecation in infants.

METHODS

A search in Cochrane Library, PubMed, OVID, Springer, China National Knowledge Infrastructure, Vip Chinese Periodical Database, Wanfang Chinese Periodical Database and Chinese Bio-medicine Database was performed to identify relevant English and Chinese language articles between January 1990 and March 2009. Two reviewers independently performed data extraction and appraised using Jadad instrument. Double data were input and analyzed by software of Review Manager 4.2 recommended by Cochrane Collaboration. Intestinal nutrient absorption, electrolyte content of fecal excretion, in vivo calcium deposition, and defecation were included as the target outcomes. These outcomes were evaluated as the combined standardized mean difference (SMD) and relative risk (RR) value and 95% CI of them.

RESULTS

Thirteen articles were included. Three articles meeting inclusion criteria were analyzed for the effects between infant formula containing palmitic acid at the Sn-2 positions and palmitic acid at the Sn-1, 3 positions; five articles were analyzed for the effects between infant formula containing palmitic acid at the Sn-1, 3 and without palmitic acid; another five articles were analyzed for the effects between infant formula containing palmitic acid at the Sn-2 positions and without palmitic acid. Absorption of fat and calcium was higher, the Ca(2+) of fecal excretion was lower when the infant formula provided palmitic acid at the Sn-2 positions or without palmitic acid than that determined when formula containing palmitic acid at the Sn-1 and Sn-3 positions was given (P < 0.01). The bone mineral content (BMC) and bone mineral density (BMD) increased at 3, 6 months when the infant formula without palmitic acid as compared with using the formula containing palmitic acid at the Sn-1 and Sn-3 positions (P < 0.01). The formation of calcium soaps in stool was reduced, the BMC increased when the infant formula provided palmitic acid at the Sn-2 positions as compared with using the infant formula without palmitic acid (P < 0.01). The incidence of soft stools was higher, and the incidence of hard stools was lower when the infant formula provided palmitic acid at the Sn-2 positions or without palmitic acid than that when formula containing palmitic acid at the Sn-1 and Sn-3 positions was used (P < 0.01).

CONCLUSION

Absorption of fat and calcium was lower, the Ca(2+) of fecal excretion was higher, the BMC was reduced, the incidence of hard stools increased when the infant formula provided the palmitic acid at the Sn-1 and Sn-3 positions as compared with using formula contained palmitic acid at the Sn-2 positions or without palmitic acid. However, this conclusion should be used cautiously because of the limited quality of studies included into the analysis.