The American journal of clinical nutrition
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Human milk contains a variety of N-acetylneuraminic acid (NANA)-containing oligosaccharides, but the expected range of intake of sialic acid in this form by infants fed human milk is unknown. Two quite different amounts have been reported: 120 mg/liter in pooled, mature human milk (1) and 1400 mg/liter in the milk of a single woman on the 1st day of lactation (2). The normal range of NANA intake in human milk glycoproteins likewise does not appear to have been analyzed previously. ⋯ During the first 2 months of lactation, milk from women delivering at term cannot be distinguished from that of women delivering significantly before term (less than 32 wks gestation) with regard to oligosaccharide and glycoprotein NANA. The parallel decrease of sialic acid in these fractions suggests a relationship between sialydation of human milk oligosaccharides and glycoproteins. Human milk NANA concentrations are discussed with regard to reports that exogenous administration of NANA can increase cerebral and cerebellar concentrations of NANA in glycoproteins and gangliosides, and produce long term changes in behavior in rats.
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Comparative Study
Glycemic responses to foods: possible differences between insulin-dependent and noninsulin-dependent diabetics.
The effect on the blood glucose response of varying the amount (25 or 50 g) and type (bread or beans) of carbohydrate (CH2O) in test meals and of adding fat and protein was examined in a group of insulin dependent and noninsulin dependent diabetic volunteers. With noninsulin-dependent diabetics, the blood glucose area after a half bread portion was 48% that of the full bread meal (p less than 0.001). ⋯ Addition to bread of butter and skim milk cheese either singly or in combination had little effect on the glycemic response although a reduced rise was seen after addition of fat and protein as peanut butter. Insulin-dependent diabetics tended to respond similarly to noninsulin-dependent diabetics but their greater variability indicates that other factors in addition to the nature of the food may also be major determinants of their glycemic responses to foods.
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Comparative Study
Elevated serum parathyroid hormone, calcitonin, and 1,25-dihydroxyvitamin D in lactating women nursing twins.
The roles of vitamin D, calcitonin, and parathyroid hormone in calcium metabolism during lactation may be more evident in women secreting very large amounts of milk for a number of months, as in mothers nursing twins. We report significant increases in serum concentrations of parathyroid hormone, calcitonin, and 1,25(OH)2 vitamin D in mothers nursing twins compared to mothers nursing single infants. ⋯ Maternal intakes of calories, calcium, and phosphorus were significantly higher in mothers nursing twins. Thus, mothers nursing twins were able to compensate for higher calcium losses in breast milk by increased dietary intakes of calcium as well as increased serum concentrations of parathyroid hormone, calcitonin, and 1,25(OH)2 vitamin D.
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Randomized Controlled Trial Clinical Trial
Modulating effect of Sustagen on plasma glutamate concentration in humans ingesting monosodium L-glutamate.
It has been suggested that monosodium L-glutamate (MSG) addition to meals would significantly increase plasma glutamate concentrations compared to values noted after ingestion of protein-bound glutamate. To test this hypothesis, plasma amino acid concentrations were measured in six normal adults ingesting a ready-to-feed liquid meal (Sustagen) containing added MSG at 0, 100, and 150 mg/kg body weight (Latin square design), and compared to plasma values noted after ingestion of 150 mg/kg body weight MSG in water. The mean (+/- SD) peak plasma glutamate concentrations after ingestion of meals providing 0, 100, and 150 mg/kg body weight MSG were 6.64 +/- 1.99, 11.2 +/- 4.89 and 10.8 +/- 3.10 mumol/dl, respectively. ⋯ In contrast, ingestion of MSG in water (150 mg/kg body weight) markedly increased the mean (+/- SD) peak plasma glutamate concentration to 71.8 +/- 35.7 mumol/dl. Similarly, the area under the plasma glutamate concentration-time-curve was significantly higher. MSG ingestion with meals results in lower plasma glutamate concentrations than ingestion of equivalent doses in water.
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Historical Article
Changes in the nutrient composition of human milk during gradual weaning.
Six lactating women were recruited at 5 to 7 months postpartum for a study of milk composition during gradual weaning. At recruitment all subjects were exclusively breast-feeding their infants. The subjects were asked to reduce the frequency or duration of breast-feeding episodes by approximately one-third each month for a period of 3 months. ⋯ The concentration of Fe at wk 12 was 172% of the base-line value. The concentration of Ca did not change and that of Zn fell to 58% of the base-line value at wk 12. The significance of the changes in nutrient concentrations, their relationship to the involution of the mammary gland, and the suitability of milk from this stage of lactation for milk banking are evaluated.