Influence of dietary nucleotides on plasma immunoglobulin levels and lymphocyte subsets of preterm infants.

We examined the effects of nucleotide supplementation to a preterm adapted milk formula on the lymphocyte subsets and plasma IgG, IgM and IgA levels in preterm infants for the first three months of life. Two groups of preterm infants received a milk formula or the same formula supplemented with CMP, AMP, UMP, GMP and IMP to mimic the concentration of acid-soluble nucleotides found in human milk. Blood samples were obtained at birth, 10 days, 20-30 days and 3 months of age. Preterm infants fed the nucleotide formula exhibited higher plasma levels of IgM in all postnatal study periods than neonates fed the standard formula; moreover, IgA was also higher at 3 months of age in nucleotide formula fed infants. No major differences were seen between groups for IgG levels and lymphocyte subsets. Thus, dietary nucleotides appear to exert actions on immature human neonate lymphocytes enhancing the in vivo production of Ig which may have a role in the defense capacity of neonates.

Gestational age and origin of human milk influence total lipid and fatty acid contents.

The human milk composition may be influenced by several factors, such as gestational age or genetic characteristics and dietary habits of different populations. To analyze the total lipid and fatty acid contents of human milk, we have conducted two studies, one on mothers who had delivered preterm and term newborns and another on mothers from two different sociocultural backgrounds (Spain and Panama). The total lipid content (g/100 g wet weight) was significantly higher in term (2.76 +/- 0.66; mean +/- SD) than in preterm mature milk (1.06 +/- 0.4). The relative amount of 18:1n-9 was significantly higher in preterm than in term milk for transitional and mature milk, whereas that for the colostrum followed the opposite trend. Concerning the comparison between milk from mothers born in different countries, the relative contents of each of the fatty acids 16:0, 16:1n-7, 18:2n-6, 18:3n-3, and 22:5n-3 were higher in Panamanian than in Spanish milk, whereas the mean percentages of saturated fatty acids < 14:0, of 16:1n-9, and of 18:1n-9 were higher in Spanish than in Panamanian milk. Statistically significant differences were found during the three periods of lactation considered for almost all the fatty acids mentioned above, especially for 18:1n-9 and 18:3n-3. Although the potential biological significance of the changes in oleic acid content between preterm and term milk remains unclear, differences in fatty acid content between Spanish and Panamanian milk reflect the different composition of the diet among women from these countries.

Plasma and red blood cell fatty acid composition in small for gestational age term infants fed human milk or formula.

The purpose of the present study was to evaluate the effects of feeding human milk or milk formula on the fatty acid composition of plasma and red blood cell (RBC) lipids in at term small for gestational age infants (SGA) for the first 3 months of life. One group of infants received a formula with a linoleic:alpha-linolenic acid ratio of 10:1 (MF group). Another group served as control and received their own mother's milk (HM group). Blood samples were taken at birth and at 1 week, 4 weeks, and 3 months of life. Plasma and RBC fatty acid composition were analyzed by gas liquid chromatography and results of total plasma lipids were expressed as concentrations by adding an internal standard. Concentrations of saturated and monounsaturated fatty acids increased in total plasma lipids with age in all infants. In contrast, those fatty acids decreased when results were expressed as percentages of total fatty acids. Long-chain polyunsaturated fatty acids (LCP) decreased regardless of how results were expressed, but the absolute concentrations of these fatty acids in plasma available for tissue accretion were greater than suggested by the percentage results. Plasma and RBC docosahexaenoic acid (22:6n-3) decreased in the MF group in comparison to the HM group. Arachidonic acid (20:4n-6) was lower in plasma of MF-fed infant but not in RBC phospholipids. We conclude that term SGA infants fed an adapted milk formula with a linoleic:alpha-linolenic acid ratio of 10:1 but devoid of LCP may lead to a low n-3 LCP status.

Changes during lactation in ganglioside distribution in human milk from mothers delivering preterm and term infants.

We studied changes during lactation in the relative concentration of individual gangliosides in human milk from mothers delivering preterm and term infants. The relative content of G(D3) was higher in colostrum than in mature milk, and tended to be higher in preterm colostrum than in term colostrum, whereas the relative content of G(M3) was higher in mature milk than in colostrum, and was also higher in term than in preterm milk. As G(D3) is usually detected in developing tissues whereas G(M3) is more abundant in mature tissues, these results suggest a relationship between the presence of individual gangliosides in human milk and immaturity of the mammary gland in mothers of preterm infants.

[Serum vitamin E in well-nourished and malnourished infants]. / Vitamina E sérica en lactantes eutróficos y malnutridos.

Vitamin E (tocopherol) concentrations in blood plasma were determined in 48 infants and correlated with their nutritional status. Infants were divided into two groups as following: group I (n : 12) estimated well-nourished, and group II (n : 36) appreciated undernourished. Clinical nutritional status was evaluated according to their weight, height and skinfold thickness of triceps percentiles. Plasma vitamin E levels were analysed by a modification of the spectrophotometric micro-technique of Fabiank et al. (using 0.2 ml of plasma). There was difference in serum tocopherol levels between two groups: 1.21 (0.21) mg/dl: mean (+/- SEM) in group I in front of 1.84 (0.18) mg/dl in group II (0.10 greater than p greater than 0.05). On the other hand, vitamin E concentrations were correlated with the skinfold thickness of triceps percentiles by a logarithm curve: y = 2.25-0.31 1n X (r: 0.35, p less than 0.02). Probably, serum vitamin E levels do not reflect the tissue store status in undernourished infants without malabsorption.