Effect of Dietary Fiber on Endogenous Cholesterol Synthesis in Infants† 1521

Abstract

Cholesterol (chol) content of infant diet varies with human milk providing≈150 mg/dl vs 11 mg/dl in commercial (Similac) infant formula. Endogenous chol fractional synthesis rate (FSR) is significantly lower in human milk vs formula fed infants (Pediatr Res 1994;35:135). Dietary fiber decreases chol absorption in adults. Parents often begin solids before the AAP- recommended 4-6 months (mon) of age, but metabolic effects of infant feeding practices are unknown. We conducted a pilot study to test the hypothesis that addition of dietary fiber to infant diet would result in higher chol FSR.Methods: 12 male term infants were fed SMA formula (chol 33mg/dl) to 1 yr of age. Subjects were randomized to begin barley cereal 8 Tbs/d (1.5g fiber/d) at the start of the 4th or 6th mon. Growth, dietary intake by 4-day records, serum chol and lipoproteins, & FSR were measured after 4 & 12 mon of age. FSR was measured using deuterium enrichment of erythrocyte membrane chol over a 4-day period (J Lipid Res 1991;32:1049). Nonparametric statistics were used. Results: There were no significant differences between groups for weight, intake, lipid, or FSR analyses. Median chol intake& synthesis rates are shown in the Table. Conclusion: In this pilot study of infants with moderate chol intake, earlier addition of dietary fiber resulted in a trend toward higher endogenous chol FSR that persisted beyond the dietary intervention.Speculation: Chol FSR during infancy may be responsive to early diet, which may have life-long implications for chol metabolism and cardiovascular disease risk. These pilot data may be used to design definitive studies of infant diet & cholesterol metabolism.