Influence of breast- and formula-feeding on plasma cholesterol precursor sterols throughout the first year of life

Relationships of carotenoid-related gene expression and serum cholesterol and lipoprotein levels to retina and brain lutein deposition in infant rhesus macaques following 6 months of breastfeeding or formula feeding

The purpose of this study was to investigate if the enhanced bioaccumulation of lutein in retina and brain of breastfed, compared to formula-fed, infant monkeys was associated with higher levels of serum total and HDL cholesterol, apolipoproteins, or mRNA/protein expression of carotenoid-related genes. Newborn rhesus macaques were either breastfed, fed a carotenoid-supplemented formula, or fed an unsupplemented formula for 6 months (n = 8, 8, 7). Real-time qPCR and western blotting were performed in two brain regions (occipital cortex and cerebellum) and two retina regions (macular and peripheral retina). Breastfed infants had higher serum total cholesterol, HDL cholesterol, apoA-I, and apoB-100 levels than the combined formula-fed groups (P < 0.05). Breast milk or infant formulas did not alter expression of the nine genes (CD36, SCARB1, SCARB2, LDLR, STARD3, GSTP1, BCO1, BCO2, RPE65) examined except for SCARB2 in the retina and brain regions. In conclusion, dietary regimen did not impact the expression of carotenoid-related genes except for SCARB2. However, carotenoid-related genes were differentially expressed across brain and retina regions. Breastfed infants had higher serum total and HDL cholesterol, and apolipoproteins, suggesting that lipoprotein levels might be important for delivering lutein to tissues, especially the macular retina, during infancy.

Enhanced delivery of lipophilic nutrients to the infant brain via high density lipoprotein

Lipoproteins are the primary carriers of lipophilic cognitive nutrients such as docosahexaenoic acid, lutein, and α-tocopherol within circulation. The critical roles these nutrients play in growth and development are well established, and as such, their efficient delivery to the infant brain is crucial. Given the selectivity of the blood brain barrier, the lipoprotein fraction primarily responsible for brain delivery of these nutrients must be determined so that efforts aimed at increasing brain nutrient uptake, via lipoprotein profile manipulation, can be appropriately focused. Based on the preclinical and clinical data reviewed here, we hypothesize that high density lipoprotein is the fraction chiefly responsible for delivery of docosahexaenoic acid, lutein, and α-tocopherol to the infant brain. As high density lipoprotein levels tend to be lower in preterm, formula-fed infants as compared to their full-term, breast-fed counterparts, efforts aimed at increasing circulating high density lipoprotein levels, and subsequent delivery of cognitive lipophilic nutrients to the brain via manipulation of formula composition, may be most effective if targeted to this group. These efforts include (1) limiting the polyunsaturated: saturated fatty acid ratio; (2) increasing the casein: whey ratio; (3) altering the proportion of saturated fatty acids found in the sn-2 position of the parent triglyceride; (4) cholesterol supplementation; and (5) nucleotide supplementation.

Reference distributions for apolipoproteins AI and B and B/AI ratios: comparison of a large cohort to the world's literature

Limiting the clinical utility of apolipoproteins AI (apo AI) and B (apo B) and the apo B/AI ratios until the last decade has been the lack of satisfactory methods for quantifying serum levels and credible reference materials. Great technological strides have been made in the last few years. The remaining barrier to more relevant and cost-effective use of serum protein data for diagnosis and prognosis has been the availability of widely recognized reliable reference intervals from birth to old age for both males and females. A total of 82 publications reporting reference intervals have been identified that meet most of the same inclusion criteria used in our prior six studies. These have been analyzed statistically and compared to similar studies, i.e., sufficient number, listed subject criteria, method, and reference material, in general terms. Published smaller studies with constrained age ranges, agree on average with our large series of life-long reference intervals that range from less than one year to over 80 years. This study was performed to assess the degree of agreement between smaller reference interval studies to our large population analysis. This meta-analysis provides support and reassurance that many of the smaller reference intervals published previously fall within reasonable limits of out large population.

Serum lipids in preterm infants fed a formula supplemented with nucleotides

BACKGROUND

The effect of dietary nucleotides on lipid metabolism has been the subject of clinical studies with conflicting results. We measured serum triglycerides, total cholesterol (total-C), and lipoprotein cholesterol levels (HDL-C, LDL-C, and VLDL-C) in preterm neonates fed formula with and without nucleotide supplements.

METHODS

This prospective, randomized, controlled study included 150 healthy preterm neonates (gestational age, 33.0 +/- 1.9 weeks) matched for gestational age, birth weight, and gender. Subjects were assigned at birth to receive either a standard milk formula supplemented with nucleotides (group F-NT) or the same formula without nucleotides (group F). Serum was obtained before discharge (29.1 +/- 10.0 days of life) and triglycerides, total-C, and HDL-C were determined enzymatically. LDL-C and VLDL-C were estimated by the Friedewald formula. For statistical analysis t test, Mann Whitney-U test, two-way ANOVA, and chi2 test were used, as appropriate. The influence of several factors on serum lipid levels was evaluated by linear regression analysis.

RESULTS

Serum triglycerides, total-C, and VLDL-C levels did not differ between groups. HDL-C levels (median; 25th-75th percentiles) were significantly higher (P < 0.001) in group F-NT (48.0 mg/dL; 40.5-57.0 mg/dL) than in group F (34.5 mg/dL; 27.2-44.0 mg/dL). On the contrary, LDL-C levels (median; 25th-75th percentiles) were significantly lower (P < 0.001) in group F-NT (39.0 mg/dL; 26.0-54.0 mg/dL) than in group F (65.0 mg/dL; 41.0-73.0 mg/dL). In the multiple regression analysis, nucleotide supplementation was identified as one of the controlled independent factors influencing serum HDL-C and LDL-C levels.

CONCLUSIONS

Preterm neonates fed from birth with formula supplemented with nucleotides have significantly higher HDL-C and lower LDL-C serum levels than do neonates fed unsupplemented formula. The clinical relevance of these results remains to be elucidated.

Birth weight, growth and feeding in infancy: relation to serum lipid concentration in 12-month-old infants

OBJECTIVE

To assess the effects of birth size, growth and feeding in infancy on serum lipids in 12-month-old infants.

DESIGN

A longitudinal observation study on infants' consumption and growth. Food and growth records were made every month. At 6, 9 and 12 months, food records were weighed to calculate intake. Serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL), low-density lipoprotein (LDL) -cholesterol and triglyceride concentrations were analysed at 12 months.

SETTINGS

Birth and growth information was gathered from maternity wards and healthcare centres in Iceland and food consumption data at home.

SUBJECTS

Randomly selected newborns (n=180) according to the mother's domicile and 77% (n=138) participated, of them 75% (n=103), came in for blood sampling.

RESULTS

Among boys, a 1 kg higher birth weight resulted in a 0.79 mmol/l higher TC (P=0.005), but nonsignificant after adjustment for growth. Duration of breastfeeding was related to LDL-cholesterol (B=0.06 +/-0.02, P=0.020, adj. R(2)=0.039), adjusting for gender. Independent of size at birth and breastfeeding, increase in length from 6 to 12 months and in weight from birth to 12 months were negatively related to TC (B=-0.455+/-0.156, P=0.008 and B=-1.086+/-0.474, P=0.032, respecitvely) in boys. PUFA was the strongest nutrient variable predicting TC (B=0.332, adj. R(2)=0.24, P>0.001). Cod liver oil consumption increased both TC and LDL-cholesterol in girls (B=0.141+/-0.051, P=0.008 and B=0.112+/-0.047, P=0.021, respectively).

CONCLUSION

Slower growth of high birth weight infants and breastfeeding contributes to higher TC concentration at the age of 12 months. Nutrient intake in infancy also affects lipid profile. The effect of birth weight, growth and nutrient intake in infancy on lipid profile is different for boys and girls.

Infant feeding and blood cholesterol: a study in adolescents and a systematic review

OBJECTIVE

To examine the influence of infant feeding method on serum total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol.

METHODS

A cross-sectional study of 13- to 16-year-olds and a systematic review of studies (all observational) on the effects of infant feeding on cholesterol in infancy (<1 year), childhood or adolescence (1-16 years), and adulthood (> or =17 years) were conducted using random effects models. Differences are presented as breastfed-bottle-fed. A total of 1532 individuals (92% white; 55% male; mean age: 15.1 years) in 10 British towns were studied, and 37 studies with 52 observations on TC (26 in infancy, 17 in childhood or adolescence, and 9 in adulthood; corresponding figures for LDL were 7, 4, and 6) were reviewed.

RESULTS

Mean TC in childhood or adolescence (including the new study) was not related to infant feeding pattern (mean TC difference = 0.00; 95% confidence interval [CI]: -0.07 to 0.07 mmol/L). However, in infancy, mean TC was higher among those breastfed (mean TC difference = 0.64; 95% CI: 0.50-0.79 mmol/L), whereas in adults, mean TC was lower among those breastfed (mean TC difference = -0.18; 95% CI: -0.30 to -0.06 mmol/L). Patterns for LDL were similar to those for TC throughout.

CONCLUSIONS

Breastfeeding is associated with increased mean TC and LDL levels in infancy but lower levels in adulthood/adult life. These results suggest that breastfeeding may have long-term benefits for cardiovascular health and may have implications for the content of formula feed milks.

Influence of dietary cholesterol on vitamin d metabolism in formula-fed preterm neonates

OBJECTIVES

Supplementation of preterm formulas with cholesterol could help to mimic the fat composition of human milk. However, this could possibly influence vitamin D 25-hydroxylation because this reaction is catalyzed in part by the mitochondrial cytochrome P-450, the enzyme responsible for the 27-hydroxylation of cholesterol. The purpose of this study was to verify whether the addition of cholesterol to preterm formulas could interfere with vitamin D metabolism in preterm neonates.

METHODS

In a prospective study, 30 preterm neonates were randomly assigned to a low (< 0.03 g/L), medium (0.15 g/L), or high (0.30 g/L) cholesterol-content preterm formula until theoretical term (i.e., 40 weeks post-conceptional age). Anthropometric data and serum hydroxy-vitamin D and 1,25 dihydroxy-vitamin D concentrations were measured at study entry and theoretical term. In a subgroup of 14 subjects, serum cholesterol and lymphocyte 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA were also assessed.

RESULTS

(median [25, 75 centiles]): At theoretical term, there were no significant differences in serum hydroxy-vitamin D concentrations among the three groups, even after adjustment for confounding variables (65 [50, 78] nmol/L, 79 [59, 86] nmol/L, and 67 [43, 103] nmol/L, respectively, = 0.65) or 1,25 dihydroxy-vitamin D ( = 0.88). Furthermore, there were no significant differences in 3-hydroxy-3-methylglutaryl coenzyme A reductase mRNA copy numbers.

CONCLUSIONS

In preterm neonates fed formulas with a cholesterol content similar to or higher than that of human milk, we did not observe deleterious effects on vitamin D metabolism. However, long-term effects of cholesterol supplementation require further studies.

Cholesterol metabolism in normal and heterozygous familial hypercholesterolemic newborns

In heterozygous familial hypercholesterolemia (FH), serum low-density lipoprotein (LDL) cholesterol levels are frequently increased in utero. A unique Finnish FH population, FH-North Karelia (FH-NK), has been identified, providing an excellent opportunity to study the diagnostic significance of cholesterol metabolism in FH. For that purpose, we investigated lipoprotein lipids, cholesterol precursors (squalene, methyl, and demethyl sterols), cholestanol, and plant sterols in FH-NK newborns (n = 5), non-FH siblings (n = 7), and controls (n = 20) at birth and after 1-year follow-up in 8 FH-NK and 5 non-FH children. The sum of concentrations (micrograms per deciliter) of methyl sterol (8-monomethylsterol, methostenol, 8-dimethylsterol, 8,24-dimethylsterol, and lanosterol) and squalene was higher in FH newborns than in non-FH siblings but overlapped with one control case. Cord-blood total or LDL cholesterol values could not be used for diagnostic purposes, whereas 1-year LDL cholesterol values were highly superior to those measured at birth. The methyl sterol ratio in cord blood was 29 to 193 10(2) mmol/mol cholesterol and was undetectable in serum at the age of 1 year; those of the demethyl precursor sterols were 1.5 to 8 times higher in cord blood than in serum at the age of 1 year, suggesting that cholesterol synthesis was markedly increased at birth. Plant sterols, not synthesized in human beings, were already present in serum of all the groups at birth, indicating their transfer, apparently with cholesterol, from mother to fetus. Babies born to FH mothers showed a greater tendency toward accelerated cholesterol synthesis than did those born to FH fathers. Despite signs of markedly high but similar synthesis of cholesterol at birth in FH and non-FH newborns, the diagnosis of FH was questionable by measurement of cholesterol precursors or LDL cholesterol in cord blood. The latter measurement, at the 1-year mark, is superior for diagnostic purposes.