Gerald E. Gaull

Effect of taurine supplementation to the diet on bile acid conjugation in low birth-weight infants (LBWI): 74

Previous results have shown that plasma and urine taurine concentrations decrease when LBWI are fed with taurine deficient formulas. In this study, 63 well LBWI with gestational ages of 31 to 36 weeks were randomly assigned to either breast milk (BM) or formula (1.5%, prot. 60:40 whey: caseins) without (F1) or with addition of taurine (30 μmol%, F2). Duodenal fluid bile acids and glycine-taurine ratio (G:T) were determined with high-performance liquid chromatography. The plasma taurine levels and urine taurine excretion fell significantly in the infants fed with the taurine deficient F1 formula. At the age of 7 days the G:T ratios were 0.64 (BM), 0.44 (F1) and 0.47 (F2). In the infants on BM and F2 the G:T ratio remained on the same level throughout the study and at the age of 36 to 40 days it was 0.58 and 0.69 respectively on the two diets. In the infants fed with formula F1, the G:T ratio increased significantly after the age of 21 days being 1.32 at a mean age of 39 days (p<0.001). Our results indicate that dietary taurine intake affects duodenal bile acid conjugation.

Milk protein quality: Biochemical and growth effects in full-term infants.

Our previous studies have shown that both quantity and quality of ingested milk protein affects the metabolic homeostasis of low birth-weight infants. In this study, 37 well full-term infants were fed ad libitum for 12 weeks with either breast milk (BM) or with one of two formulas (F1=1.5% prot., whey prots.: caseins, 60:40 or F2=1.5% prot.; whey prots.: caseins, 18:82). No differences between feeding groups were found in weight gain, linear growth or head circumference during the study period. Significantly, greater negative base excess and higher BUN were found in the formula fed infants as compared to those on BM. Blood cholesterol at 12 weeks was much higher in the infants on BM when compared to those on F1 and F2 (p<0.0001). Plasma and urine taurine concentrations were higher in the infants on BM throughout the study and at 4, 8 and 12 weeks of age the urine taurine was 25 to 50 times higher in BM infants than in F1 and F2 infants. Plasma valine and isoleucine concentrations were significantly increased in the formula fed infants as was the valine/glycine ratio, suggesting the possibility of protein overloading in the formula fed infants.

570 EFFECTS OF VARIOUS VOLUMES OF POOLED HUMAN MILK (PHM) IN PRETERM INFANTS (PTI)

PHM reduces metabolic cost during growth, although its nutritional sufficiency is debated. We report growth and metabolic comparisons amongst PTI (gest. age T2=31-33, T3=34-36 wks) fed 170 (group A), 185 (B) and 200 ml/kg/day (C) of PHM and compare results among groups and with breast-fed, full-term infants (FTI).No consistent differences among A, B, & C were observed in measures of linear growth or head circ. PTI in B (T2=104±12, T3=116±4 g/kg/wk) and C (T2=110±16, T3=108±8) gained weight more rapidly than those in A (T2=95±8, T3=83±16).Serum alb did not differ among A, B, & C but was lower in A, B & C than in FTI. After the first 2 weeks, mean pH in B & C approached that in FTI (7.39), whereas A remained signif lower (7.32-7.36). Base excess in A remained lower than in FTI; plasma bicarbonate was lower in A, B, & C than in FTI. BUN was lower in A than in FTI and intermediate and variable in B & C. Plasma amino acids fell into three groups: (1) A was lower than B, C or FTI (tau, met, cys, ser, gly, asp); (2) FTI was higher than A, B, or C which did not differ (glu, gluNH2, ala, leu, ileu, val, tyr, phe); (3) no differences (thr and cit).Thus, while PHM in PTI gives adequate growth without undue metabolic cost, 185-200 rather than 170 ml/kg/day may be required.

EFFECTS OF QUANTITY AND QUALITY OF MILK PROTEIN ON AMINO ACID AND PROTEIN METABOLISM OF PREMATURE INFANTS

105 prematures, divided into 3 gestational age groups, received either human breast milk /BM/ or one of four isocaloric formulas which provided the following protein intakes /g/kg/day/: F1=2.2; F2=4.4 /casein: whey prot=40:60/ F3=2.2; F4=4.4 /casein: whey prot=82:18/ BUN was elevated in infants on the high protein diets. Total plasma proteins and A/G ratio reflected the amount of protein in the diet. The essential amino acids in plasma and urine; phe, met, thr, leu, ileu, val, and in addition tyr, correlated with both quantity and quality of ingested protein. Plasma phe and tyr were 10–100 times higher in small infants on F4 when compared to infants on BM or F1. Urinary cystathionine was elevated in infants fed diet F4. There were no significant differences in other plasma and urine amino acids. Physical growth was similar both in formula-fed and in BM-fed infants. The plasma amino acid imbalance produced by high protein/high casein diets, without accelerated growth, makes the use of these diets in pre-term infant feeding questionable.