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Infant diet affects serum lipoprotein concentrations and cholesterol esterifying enzymes in baboons
G E Mott1, D S Lewis, C A McMahan
1Department of Pathology, University of Texas Health Science Center, San Antonio.
Insights
Breast milk significantly impacts infant cholesterol metabolism, leading to higher serum cholesterol and specific lipoprotein profiles compared to formula feeding. Formula fat composition had minimal effect on these preweaning differences.
Area of Science:
- Biochemistry
- Pediatrics
- Nutritional Science
Background:
- Infant nutrition significantly influences early-life development.
- Cholesterol metabolism plays a crucial role in infant health and long-term outcomes.
- Understanding differences between breast milk and infant formula is vital for optimizing infant nutrition.
Purpose of the Study:
- To compare preweaning cholesterol metabolism in breast-fed versus formula-fed baboons.
- To evaluate if infant formulas with varying polyunsaturated:saturated fatty acid (P:S) ratios mimic breast milk's effects.
- To identify factors contributing to metabolic differences between breast milk and formula.
Main Methods:
- Longitudinal study involving 45 infant baboons assigned to breast-fed, low P:S formula, or high P:S formula groups.
- Analysis of serum cholesterol, lipoprotein concentrations (HDL1, HDL2, HDL3, LDL), and apolipoproteins (A-I, B, E).
- Measurement of hepatic acyl CoA:cholesterol acyltransferase (ACAT) and plasma lecithin:cholesterol acyltransferase (LCAT) activities, and post-heparin lipoprotein lipase (LPL) activity.
Main Results:
- Breast-fed infants exhibited higher overall serum cholesterol, driven by increased HDL1 and HDL2, but lower HDL3 compared to formula-fed groups.
- Low P:S formula-fed infants showed higher LDL-cholesterol; breast-fed infants had higher apolipoprotein E.
- Breast-fed infants displayed higher hepatic ACAT activity and lower plasma LCAT activity, with greater LPL activity than formula-fed infants.
Conclusions:
- The polyunsaturated:saturated fatty acid (P:S) ratio in infant formulas has a limited impact on preweaning cholesterol metabolism.
- Metabolic differences observed between breast-fed and formula-fed infants are likely due to factors beyond the fat composition of the formula.
- Further research is needed to elucidate the specific components in breast milk responsible for its unique metabolic effects on infants.
Abstract:
We characterized the preweaning differences in cholesterol metabolism between breast-fed and formula-fed baboons and determined if formulas with low and high polyunsaturated:saturated fatty acid (P:S) ratios simulated the effects of breast feeding. At birth, 45 infant baboons from three sires and 44 dams were assigned to breast-fed, low P:S formula or high P:S formula diet groups until weaning at 14 wk. From 4 to 14 wk breast-fed infants had higher serum cholesterol because of much higher HDL1- and HDL2-cholesterol concentrations but had lower HDL3-cholesterol than both formula-fed groups. LDL-cholesterol was higher in infants fed the low P:S fomula. Breast-fed infants had higher serum apolipoprotein E than the formula-fed groups, but diet did not affect apolipoprotein A-I or B concentrations. Breast-fed infants had higher hepatic acyl CoA cholesterol acyltransferase activity and lower plasma lecithin cholesterol acyltransferase activity. These enzyme activities were not different between infants fed low or high P:S formulas. Post-heparinized plasma lipoprotein lipase activity was greater in breast-fed infants than in those fed formula. These findings demonstrate that the P:S ratio of formulas has little effect on cholesterol metabolism during the preweaning period and suggest that factors other than fat composition account for the metabolic differences between breast feeding and commercial infant formula.