Héctor Bourges

Amino acid profiles in diet, plasma and human milk in Mexican rural lactating women

Abstract This study was designed to assess the relation between the amino acid pattern consumed by marginally nourished lactating women, and the amino acid profiles in plasma and milk. Ten lactating women from a Mexican rural community, with an age of 19–29 (y), a postpartum time 15 (w), and a weight of 49 (kg), were studied in a metabolic unit. Experimental diet was similar to the rural habitual diet and it was given for 10 days. On the last 4 days urine, feces, milk and blood samples were collected. Measurement of total nitrogen in urine, feces and diet, and amino acid analysis in diet, plasma and milk were performed. Amino acid score of the habitual diet was: Lys as a limiting amino acid (18.5%), and Phe+Tyr (137.9%) in excess. Lys intake (21.8 ± 4.6 mg/g protein) was lower than the consumption recommended for lactating women (31 mg/g protein). Nitrogen balance was −9.6 ± 15.4 mg/kg BWd. Total amino acid concentration in plasma was: 2212.6 ± 176.4 μmol/L, where indispensable and dispensable amino acids were 33% and 67% respectively; the most abundant amino acids were Ala, Glu, Gly, Lys and Val; and the less abundant were Cys and Asp. Total amino acid concentration in milk was: 24090 ± 1228 μmol/L, containing 42% and 58% of indispensable and dispensable amino acids respectively; the most abundant amino acids were Glu, Pro and Leu, and the less abundant were Cys, Trp, and Met. The results showed a correlation between the concentration of some indispensable amino acids present in the diet with those of milk (p

Regulation of histidase gene expression by glucagon, hydrocortisone and protein-free/high carbohydrate diet in the rat

The effect of glucagon and hydrocortisone was investigated to understand the mechanism of induction of hepatic histidase gene. In this study, glucagon (0.6 mg/100 g body wt/d) was injected to rats fed 10% casein diet. After 3 h of the last injection, histidase activity and amount of enzyme were induced by 3 fold and histidase mRNA concentration by 6 fold. Injection of hydrocortisone (2 mg/100 g body wt/d) increased 100% histidase activity and mRNA concentration and by 150% the amount of enzyme after 3 h of the last injection. These results indicate that glucagon is a better inductor of histidase gene expression than hydrocortisone. Another purpose of the study was to evaluate if a protein-free/high carbohydrate diet could reverse the induction of Hal expression produced by a high protein diet. Hal activity, amount of enzyme and mRNA concentration was repressed by 68, 88 and 95% respectively by a protein-free/high carbohydrate diet. Injection of glucagon reversed partially the effect of a high carbohydrate diet, however, injection of hydrocortisone under the concentration used in these experiments did not reverse the effect of a high carbohydrate diet. These results support the evidence that hepatic histidase gene expression is probably regulated transcriptionally by hormones.

Metabolizable energy from a predominantly vegetable diet consumed by Mexican rural lactating women

Abstract Metabolizable energy from the habitual diet was measured in lactating women from a Mexican rural community. Food intake was estimated in 12 women, age 25 ± 5 y, 2–6 m postpartum, body weight 48 ± 4 kg and height 147 ± 4 cm. Rural diet was predominantly from vegetable sources based on maize (tortillas), beans, tomato, onion and chili. The group was studied in free conditions with their habitual diet intake and in balance conditions consuming a controlled diet similar to their rural diet. Four women participated in a second balance with a modified diet, low in fiber and higher in protein and fat content in comparison with the habitual rural diet. Metabolizable energy was lower (P 22%) than with the rural diet. Metabolizable energy from the rural diet by the lactating women group was lower (8.1 MJ/d) than the energy recommended allowances during lactation. Nutrient digestibility from the rural diet was similar to those found in populations with intake of predominantly vegetable diets with high dietary fiber content.