The effect of different protein hydrolysate/carbohydrate mixtures on postprandial glucagon and insulin responses in healthy subjects.

OBJECTIVES: To study the effect of four protein hydrolysates from vegetable (pea, gluten, rice and soy) and two protein hydrolysates from animal origin (whey and egg) on glucagon and insulin responses. SUBJECTS/METHODS: Eight healthy normal-weight male subjects participated in this study. The study employed a repeated-measures design with Latin square randomization and single-blind trials. Protein hydrolysates used in this study (pea, rice, soy, gluten, whey and egg protein hydrolysate) consisted of 0.2 g hydrolysate per kg body weight (bw) and 0.2 g maltodextrin per kg bw and were compared to maltodextrin alone. Postprandial plasma glucose, glucagon, insulin and amino acids were determined over 2 h. RESULTS: All protein hydrolysates induced an enhanced insulin secretion compared to maltodextrin alone and a correspondingly low plasma glucose response. A significant difference was observed in area under the curve (AUC) for plasma glucagon between protein hydrolysates and the maltodextrin control drink (P<0.05). Gluten protein hydrolysate induced the lowest glucagon response. CONCLUSIONS: High amino-acid-induced glucagon response does not necessarily go together with low insulin response. Protein hydrolysate source affects AUC for glucagon more profoundly than for insulin, although the protein load used in this study seemed to be at lower level for significant physiological effects.

Erythrocyte and plasma cholesterol ester long-chain polyunsaturated fatty acids of low-birth-weight babies fed preterm formula with and without ribonucleotides: comparison with human milk.

We investigated whether a regular formula for premature infants (pre) supplemented with ribonucleotides (pre+RN) raises erythrocyte and plasma cholesterol ester (CE) long-chain polyunsaturated fatty acids (LCPUFAs) of low-birth-weight babies (< or = 2.50 kg) compared with their breast-fed counterparts. From days 11 to 42, 31 babies received the pre formula and 37 received pre+RN. Eleven breast-fed babies served as a reference group. Erythrocytes and CE fatty acids were determined on days 11, 21, and 42. There were no differences in the courses of erythrocytes and CE fatty acids between pre formula-fed and pre+RN-fed babies. On day 42, formula-fed babies had lower erythrocytes and CE n-3 and n-6 LCPUFAs compared with breast-fed babies. Subdivision into gestational age- and body weight-matched subgroups gave similar results. RN supplementation does not augment the erythrocyte and CE LCPUFA status of formula-fed babies.

Composition of premature breast-milk during lactation: constant digestible protein content (as in full term milk).

There is much discussion about the protein requirements of (very) preterm infants. The protein content of breast milk plays an important role in this discussion. For this reason, we took a close look at the protein content and its composition in premature breast milk. Complete 24 h expressions-were examined using the Kjedahl method, GPC, SDS-PAGGE and nephelometric detection of sIgA. Colostrum of premature breast milk contains a large amount of undigestible proteins, up to 70% of true protein, which decreases to 20-40% in transitory and mature preterm milk. The NPN fraction of mature preterm breast milk was, dependent on the degree of prematurity 20-25%; increasing during lactation from about 18% to 22-26%. This means that, depending on the lactation period only 30-60% of the total protein content of breast milk is available for body protein synthesis. In absolute amounts, digestible protein is reasonably stable during lactation.