Human nutrition. Clinical nutrition最新文献

Factors associated with the rickets found in children attending the Outpatients Department of Cairo Children's Hospital have been studied. All the children studied were small for their age with the rachitic children being significantly smaller than the controls. The clinical diagnosis of the disease was confirmed in 54 children by X-ray and plasma biochemistry. The best indicator of the disease was the enlarged epiphysis of the wrist and to a lesser extent that of the ankles. Some of the factors predisposing to rickets were assessed in the rachitic children and in age-matched controls. There was no difference in the nutrient intake of these two groups of children although intakes of energy, calcium and vitamin D, but not of protein, were lower than recommended dietary allowances. Although more of the rachitic children came from urban areas than the controls there were no significant differences in the environments to account for the occurrence of the disease. Factors contributing to the development of rickets are discussed with particular regard to aspects such as low body weight, low maternal vitamin D status and low calcium intakes which cause a high rate of utilization and metabolism of vitamin D.

A method is proposed for calculating nutrient utilization rates from measurements of respiratory gas exchange by considering the balance of the elements C, O, H, N and S, without the need to define the pathways of intermediary metabolism. This approach enables the sources of error in the calculation of nutrient utilization to be readily identified, and their effect on precision to be assessed in different nutritional and metabolic states. Equations have been derived for calculating fat and carbohydrate utilization in the fed state. These are different from the conventional equations, which were intended for use in the fasted state. They take account of variations in the compositions of fat, carbohydrate and protein in the nutrients utilized, whether from the body stores during fasting or from the diet during feeding. Examples of the use of these equations show that failure to account adequately for the composition of food or nutritional support regimens can cause avoidable errors in the calculated rates of fat and carbohydrate utilization.

Sixty-six children with satisfactory growth and 73 with unsatisfactory growth (both sexes) from three different age groups (1 year, 5 years and 10 years) were included in this study. It was observed that the serum concentrations of human growth hormone (hGH) in children with satisfactory growth ranged from 1.00 to 4.00 ng/ml and never exceeded 4.00 ng/ml. In a comparative study there was a significant increase in serum hGH levels in subjects of all age groups who were not growing satisfactorily. Twelve children between 12 and 13 months of age with unsatisfactory growth were nutritionally rehabilitated for 4 months and the changes in weight and serum hGH levels were assessed monthly. The results indicated a definite fall of hGH level after rehabilitation and reached the normal level 3 months after rehabilitation. Moreover, an inverse relationship between body weight and serum hGH level was observed.

Rates of oxygen consumption and carbon dioxide production have been measured in healthy adults during 4 h of fasting followed by 4 h of hourly small meals. Both rates rose to new steady values during feeding, and the respiratory quotient (RQ) increased from 0.792 to 0.924. The RQ was consistent in repeat studies on any individual (coefficient of variation: 2.5 per cent), and differences between individuals were significant in the fasted but not the fed state. Simultaneous measurements were made of the rate of protein oxidation by primed constant infusion of (1-13C)leucine for 8 h. Rates were calculated from the enrichment of plasma alpha-ketoisocaproate and the production of 13CO2 in the breath, taking account of the incomplete recovery of 13CO2 and the changes in baseline enrichment resulting from natural 13C in the food. Leucine oxidation increased by 87 per cent during the feeding period. Rates of nutrient utilization were calculated from respiratory gas exchange and rates of protein oxidation. These showed that fat was predominant in the fasted state, contributing 61 per cent of total energy expenditure, compared with 27 per cent for carbohydrate and 11 per cent for protein. On feeding there was a switch to carbohydrate as the main fuel (62 per cent), with smaller contributions from fat (20 per cent) and protein (18 per cent). During feeding total utilization of each nutrient exceeded its intake from the diet, indicating storage in the body. Dietary carbohydrate was stored without conversion to fat. It is concluded that this method is useful for studying the control of nutrient utilization by food intake.

Nutritional factors associated with intrauterine growth retardation (IUGR) were studied in 118 mothers, from an inner London population, 24-48 h after delivery. Lower socio-economic status, smoking and, in the diet, only a low dietary intake of zinc were significantly associated with IUGR. It is suggested that women at risk of delivering babies small-for-gestational-age might benefit from an increased zinc intake.

Totally gastrectomized patients could be regarded at risk for development of nutritional deficiencies including trace elements. Sensitive indices for early detection of these deficiencies are lacking. In order to evaluate the nutritional status of trace elements in patients previously subjected to a total gastrectomy we studied the zinc status in 10 patients by determining serum zinc, urinary zinc excretion and also, by a simplified dark adaptation test, the effect on these parameters of 4 weeks of zinc supplementation. The serum zinc level but not the 24-h urinary zinc excretion was lower in gastrectomized patients compared to age-matched controls. A slower dark adaptation was observed in the former patients when measured in the non-fasting state but not when fasted. Dark adaptation was slower in the patients as well as the age-matched controls compared to younger healthy subjects. Zinc supplementation increased the serum zinc levels and the urinary zinc excretion in the gastrectomized patients but had no effect on dark adaptation.

The role of diet-induced thermogenesis (DIT) in the regulation of energy utilization in preterm infants was investigated by measuring energy expenditure and nutrient deposition in groups of subjects fed either banked drip breast milk (BBM) or a preterm formula (PF). Nutrient deposition was determined by combining a 3-d nutrient balance study and measurement of energy expenditure. Infants fed PF consumed 57 per cent more metabolizable energy (ME) than those fed BBM. There were significant differences between groups in energy expenditure, energy deposition and protein deposition; 76 per cent of the additional ME intake consumed by the PF-fed group was deposited while the remaining 24 per cent was expended. Infants fed PF gained weight 39 per cent faster than those fed BBM (19, compared to 14 g/kg/d), and deposited 128 per cent more fat and 86 per cent more protein. These findings indicate that nutrient deposition, rather than DIT, was the primary use of the extra ME received by the infants fed PF. However, the effect of the high energy intake on weight gain in these subjects was reduced, compared to its effect on nutrient deposition, by increases in the concentrations of fat and protein in new tissue.

Relatively little is known about the response of the human body to perturbations in the energy intake. In particular, results of the effect of a perturbation of the preceding day's energy intake on the energy expenditure on the following day are conflicting, ranging from no effect at all to an increase in the resting metabolic rate of 12 per cent following an increase in the preceding day's energy intake of 5 MJ. In the present study, the fasting energy expenditure of rest, light arm work and light leg work was determined on days following an intake of 4, 10 and 16 MJ in seven healthy men. In each subject, the difference in energy expenditure between days following intakes on the preceding day of 10-10 (control), 10-4 and 10-16 MJ was calculated for each of the three tasks. The mean percentage differences between the days following an intake of 10-10, 10-4 and 10-16 MJ were (s.d. in parenthesis) 0.0 (4.0), +1.3 (4.0) and +0.6 (3.2) for the resting metabolic rate, -1.7 (4.0), -2.2 (3.2) and -1.7 (3.7) for arm work and +0.3 (2.0), -1.2 (2.9) and -0.3 (3.2) for leg work. When the differences for the three tasks were averaged, the results were -0.5 (1.4), -0.7 (2.4) and -0.5 (1.3) for the three combinations respectively. None of these differences were found to be statistically different from zero. Changes in plasma adrenaline and noradrenaline concentrations were also measured but found not to be related to the changes in energy expenditure or to the energy intakes.(ABSTRACT TRUNCATED AT 250 WORDS)

Total daily energy expenditure (TDEE) and energy expended in activity (EAc) were estimated in 24 control (nutritionally normal) and 20 marginally undernourished girls, 8-11 years of age, before and after a dietary intervention which supplied an average of approximately 600 kcal/d only to the undernourished subjects. In the latter, the velocity of weight gain was significantly increased after dietary supplementation as were skinfold thickness and mid-arm circumference. EAc was not diminished in the undernourished subjects nor did it increase following dietary supplementation. It is suggested that in school-aged children, peer pressure to keep up with activities in school and play may attenuate the reduced activity sometimes seen in preschool and adult subjects as a response to restricted energy intake. Instead, at marginal levels of malnutrition, reduced growth in the school-aged group may be the first level of response with reduced physical activity seen only at more severe levels of nutritional deprivation.

The present report is a continuation of our earlier studies on the complex interaction between undernutrition and leprosy. Serum levels of vitamins A and E, zinc and iron were determined in healthy control subjects and lepromatous leprosy patients belonging to an eastern state of India. Results indicated a significant lowering in the two above-mentioned fat-soluble vitamins and also a remarkable hypozincaemia in the patient group. However, serum iron levels were found to be comparable in both the groups. Also concentrations of vitamin A transport proteins such as retinol binding protein and prealbumin in sera of the lepromatous patients were significantly decreased in comparison with the control subjects. Of the two zinc-binding proteins, ie, serum albumin and alpha-2 macroglobulin, only the former was significantly reduced in the patient group. Surprisingly, though serum iron, transferrin and ferritin levels were similar in both the patient and control groups, the haemoglobin levels were significantly reduced in the lepromatous patients. The implications of these findings have been discussed. This is the first report describing the serum ferritin levels in lepromatous patients.