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Biomedical subjects

D V Barclay

Publications and source records attributed to D V Barclay.

8 recordsLinked to original sources
PubMed2004

Effects of usual nutrient intake and vitamin D status on markers of bone turnover in Swiss adolescents.

OBJECTIVE: To evaluate the effects of nutrient intake and vitamin D status on markers of type I collagen formation and degradation in adolescent boys and girls. DESIGN: Cross-sectional study. SETTING: Canton of Vaud, West Switzerland. SUBJECTS: A total of 92 boys and 104 girls, aged 11-16 y. Data were collected on height, weight, pubertal status (self-assessment of Tanner stage), nutrient intake (3-day dietary record) and fasting serum concentration of 25-hydroxyvitamin D (25OHD), and markers of collagen formation (P1NP) and degradation (serum C-terminal telopeptides: S-CTX). RESULTS: Tanner stage was a significant determinant of P1NP in boys and girls and S-CTX in girls. Of the nutrients examined, only the ratio of calcium to phosphorus (Ca/P) was positively associated with P1NP in boys, after adjustment for pubertal status. 25OHD decreased significantly at each Tanner stage in boys. Overall, 15% of boys and 17% of girls were identified as being vitamin D insufficient (serum 25OHD <30 nmol/l), with the highest proportion of insufficiency at Tanner stage 4-5 (29%) in boys and at Tanner stage 3 (24%) in girls. A significant association was not found between 25OHD and either bone turnover marker, nor was 25OHD insufficiency associated with higher concentrations of the bone turnover markers. CONCLUSIONS: The marked effects of puberty on bone metabolism may have obscured any possible effects of diet and vitamin D status on markers of bone metabolism. The mechanistic basis for the positive association between dietary Ca/P ratio and P1NP in boys is not clear and may be attributable to a higher Ca intake per se, a critical balance between Ca and P intake or higher dairy product consumption. A higher incidence of vitamin D insufficiency in older adolescents may reflect a more sedentary lifestyle or increased utilisation of 25OHD, and suggests that further research is needed to define their requirements. SPONSORSHIP: Nestec Ltd and The Swiss Foundation for Research in Osteoporosis.

Adolescent↗
PubMed1996

Nutritional status of institutionalised elderly in Ecuador.

The nutritional status of 111 elderly men and women aged 60 to 99 years in two institutions in the Ecuadorian Andes was evaluated using dietary, anthropometric and biochemical measurements. Mean daily energy intakes of men and women were 1720 and 1650 kcal, respectively (7.2 and 6.9 MJ), corresponding to 1.5 times the calculated basal metabolic rate (BMR). 6% of subjects had intakes less than 1.2 x BMR and 40% less than 1.5 x BMR. Body mass index (BMI) was below 20 kg/m2 in 21% of subjects; 45% were between 20 and 24. Only one subject had a BMI over 29. Intakes of protein, calcium, iron, riboflavin and vitamin C were satisfactory, in contrast to those of zinc, vitamin A, niacin and thiamin. Using sex- and altitude-specific cutoffs for hemoglobin, anemia was observed in 11% of subjects. Nutritional status, evaluated using biochemical indicators, was satisfactory with respect to riboflavin, vitamin A, vitamin E and copper. 14% of subjects had low serum zinc levels and 17% had serum albumin values below 35 g/L. Low physical activity was associated with low energy intake and low serum albumin levels.

Aged↗
PubMed1995

Calcium bioavailability from a calcium- and sulfate-rich mineral water, compared with milk, in young adult women.

Some mineral waters have a high calcium content and may contribute a significant part of the human daily requirements. Calcium bioavailability from a calcium- and sulfate-rich mineral water (CS-W) containing 11.2 mmol Ca/L (467 mg/L) was compared with that from milk in nine healthy young women. Calcium absorption was measured in the fasting state with a dual-label stable-isotope technique. Fractional absorption rates from milk and CS-W were 25.0 +/- 6.7% and 23.8 +/- 4.8% (means +/- SD), respectively, and did not differ significantly (P = 0.05). Urine was collected for 36 h after the administration of the oral stable isotope while the subjects consumed a controlled diet and a quantity of milk or CS-W providing 25 mmol (1000 mg) Ca. No significant difference was found in the excretion of calcium, nor in the excretion of the two stable isotopes. Mean urinary sulfate excretion was significantly increased by 35% when the CS-W was consumed. No significant correlation was found between 36-h urinary excretion of the intravenous calcium tracer and sulfate, sodium, or urine volume. Therefore, calcium from the CS-W was as well absorbed and retained as that from milk, and no calciuric effect of sulfate was found, showing that such mineral waters can be valuable dietary sources of calcium.

Administration, Oral↗
PubMed1995

A packaged rice-based oral rehydration solution for acute diarrhea.

In a 12-month community study in Ecuadorian preschool children, we compared a packaged rice-based oral rehydration solution (R-ORS) that contained 160 g of rice flour and 12 g of sucrose per liter as well as electrolytes and alpha-amylase, and required cooking before consumption, to the standard glucose-electrolyte oral rehydration solution (G-ORS) for the treatment of acute noncholera diarrhea. The reconstituted R-ORS had energy and protein contents of 620 kcal/L and 12g/L, respectively, and an osmolarity of 230 mosm/L. In all, 156 cases were treated with the R-ORS and 144 with the standard G-ORS. Cases treated with R-ORS had a significantly shorter duration of diarrhea (p < 0.0001; median; 34 h versus 48 h), a lower number of stools (p < 0.001; median; four versus seven), and a greater weight gain after 4 days of treatment (p < 0.05; mean; 1.6% versus-0.2%) than those treated with G-ORS. ORS and total liquid intakes tended to be higher with the R-ORS. The two ORS were equivalent for the correction of mild dehydration and the maintenance of normal hydration status.

Acute Disease↗
PubMed1994

Altitude correction for hemoglobin.

OBJECTIVE: To propose a correction for the hemoglobin (Hb) increase induced by altitude-associated hypoxia. DESIGN: Part of a national study of nutrition and health of preschool children (0-59 months), based on a stratified, probabilistic, cluster sample. SETTING: Coastal and Andean regions of Ecuador, comprising about 97% of the population, living at altitudes ranging from sea level to 3400 m. SUBJECTS: Subsample of 469 girls and boys, 6-59 months old, with normal iron (Fe) status parameters, i.e serum ferritin > or = 10 micrograms/l, transferrin saturation > or = 12%, zinc protoporphyrin < or = 2.8 micrograms/g Hb. RESULTS: Exponential regression curves are adapted through the Hb values of the children, grouped by altitude ranges, and through the data reported by Hurtado in 1945 for male adults. From these exponential curves, correction factors for Hb are derived for altitudes ranging from sea level to 3400 m. CONCLUSION: The striking parallelism between the hypoxia-induced hemoglobin increase with altitude in young children (girls and boys) and that in male adults strongly suggests that the proposed correction factors for Hb are applicable for all ages and possibly both genders, at least in the Andes.

Adult↗
PubMed1991

Breast-milk calcium and phosphorus concentrations of mothers in rural Zaire.

The breast-milk calcium and phosphorus concentrations of 12 mothers living in a poor, rural area of Zaïre have been measured serially over 18 months of lactation. Calcium concentrations remained steady for the first 3-4 months and then decreased by approximately 27%. Phosphorus concentrations decreased by an average of 16% during the first 6 months and then reached a low plateau. The calcium:phosphorus ratio decreased from 1.7 in early lactation to 1.3 after 15 months. A wide range of mineral concentrations was observed between individuals in Zaïre and the differences between mothers were maintained throughout lactation. No influence of maternal nutritional status, age or parity on breast-milk mineral concentrations was observed. Comparison of the results of this study with published data from Britain and The Gambia obtained in the same laboratory demonstrated that breast-milk calcium concentrations in Zaïre resembled Gambian values in being significantly lower than those in Britain by 15%-20%. In contrast, breast-milk phosphorus concentrations in Zaïre were similar to those in Britain and were lower than those in The Gambia. This pattern of mineral composition resulted in Ca:P ratios in Zaïre that were intermediate in value between those of British and Gambian breast-milk. More information is required about the factors which determine calcium and phosphorus secretion into breast-milk.

Calcium↗
PubMed1982

Plasma amino acid responses in humans to evening meals of differing nutritional composition.

The effect of a carbohydrate or a 20% protein (HP) or a carbohydrate + 0.4% tryptophan (TRP) evening meal on plasma amino acids and on plasma neutral amino acid (NAA) ratios was studied in eight healthy men. After consumption of the protein meal, plasma amino acids rose after 1 h and remained at the same level at 2 h. The dietary profile of the essential amino acids, except for TRP, was retained in the plasma. The plasma profile of nonessential amino acids was not related to the dietary pattern. Glutamic acid and aspartic acid increased several-fold less and alanine several-fold more than would be expected from their dietary concentrations. The tyrosine/NAA and phenylalanine/NAA ratios were not altered by any of the meals and the TRP/NAA ratio was increased only by the carbohydrate + 0.4% TRP meal. The leucine/NAA and isoleucine/NAA ratios were decreased by the carbohydrate and carbohydrate + TRP and increased by the 20% protein meals, while valine/NAA was decreased by the carbohydrate + TRP and HP but increased by the carbohydrate meal. From these data it is concluded that if brain neurotransmitter synthesis is controlled by the same mechanisms as in rats, then the evening meal containing added TRP was the only one of the meals likely to affect brain neurotransmitter (serotonin) synthesis.

Adult↗