The main purpose of the present study was to examine factors that affect bone mineral density (BMD) in female ballet dancers. Training history, Ca intake, body composition, total body BMD (TBMD) and site-specific BMD, and bone mineral content were described in twenty-four female ballet dancers (mean age 22·6 (SD 4·5) years). Training history was determined by questionnaires, Ca intake by 7 d dietary record, BMD and bone mineral content by dual-energy X-ray absorptiometry (DXA), total body water by 2H dilution, extracellular water by bromide dilution, body fat by underwater weighing (UWW; two-component model), DXA, and the four-component (4C) model. Dancers had a significantly lower body mass index (BMI 18·9 (SD 1·0) kg/m2) than controls (21·3 (SD 19) kg/m2), with significantly lower percentage body fat (17·4 (SD 3·9) v. 24·4 (SD 5·1)) but comparable fat-free mass. Mean TBMD (1·147 (SD 0 ·069) g/cm2) was significantly higher (6 %) compared with that of a reference population. These high values could be attributed to the high BMD of legs and pelvis, the weight-bearing sites of the dancer's body. No relationship was found between age, start of ballet classes, period (years) of dancing, Ca intake, and BMD (total and site-specific). However, TBMD was positively related to BMI, and negatively related to the age of menarche. BMD of the legs was significantly related to daily period (h) of training. Depending on the method used the percentage body fat ranged from 16·4 (by DXA) to 18·3 by the 4C model. These differences were significantly related to the TBMD. Percentage body fat by the different methods was not significantly different, except for DXA and 4C model. The present study showed that, despite the factors that have a negative effect on BMD, such as low body mass and late menarche, BMD in female ballet dancers was relatively high. These high values were probably caused by high levels of weight-bearing physical activity.

The Department of Health (1992) has recently stated that ‘Nutritional reviews concerning elderly people are especially constrained by lack of data’, and that much of the emphasis in the nutritional literature has been placed on the study of institutionalized, and often chronically ill, elderly subjects rather than the non-institutionalized elderly who form the majority of this population. The present study presents information on the dietary intake and biochemical status of non-institutionalized elderly subjects (68–73 and 74–90 years) and compares such data with those obtained for adult (20–64 years) and adolescent (13–14 years) populations living within the same community. Nutrient intakes and appropriate biochemical measurements of nutrient status, performed on fasting blood samples, were statistically examined and have been discussed in relation to potential age-related influences. The nutrient intake of elderly subjects was on a par with adolescents of corresponding sex but generally lower than that of adult counterparts. There were several significant differences in biochemical measurements of nutrient status between age groups. In general these did not suggest progressive age-related trends. However, there were significant suggestions of age-related increases in whole-blood glutathione peroxidase (EC 1·11·1·9) activity, serum ferritin, plasma cholesterol, LDL and triacylglycerol concentrations and decreases in plasma HDL and ascorbic acid concentrations. The significance of these differences is discussed. An age-related difference (suggestive of a decline) in vitamin C status together with a difference (suggestive of an increase) in glutathione peroxidase activity may indicate an imbalance in the regulation of O2-derived free-radicals with ageing. These observations are worthy of a further study in the light of current thinking which relates the induction of a number of diseases to oxidative damage.

The effects of fasting on the thermogenic, lipolytic and cardiovascular responses to adrenaline were examined in nine normal, young, non-obese subjects. Each subject attended for study after 12, 36 and 72 h fasting. After basal measurements adrenaline was infused at 25 ng/min per kg ideal body weight for 90 min. Fasting increased the thermogenic effect of the adrenaline (mean 14·6 (SE 1·7), 16·6 (SE 1·8), 22·6 (SE 1·6) J/:min per kg fat-free mass after 12, 36 and 72 h fasting respectively; P < 0·001, ANOVA). Basal plasma palmitate turnover increased with duration of fasting (1·48 (SE 0·22), 1·95 (SE 0·34) and 2·26 (SE 0·33) μmol/min per kg body weight: P < 0·001, ANOVA), but the response to adrenaline was unaffected by fasting. The percentage values for basal plasma palmitate turnover oxidized were 44 (SE 2; 12 h), 46 (SE 5; 36 h) and 42 (SE 4)% (72 h). In response to adrenaline this percentage fell, suggesting that adrenaline infusion may favour intra-tissue lipid oxidation.

The ‘single-dose end-product’ approach for the measurement of protein turnover is the only method suited for application to free-living individuals and for field studies. However, the method has never been widely accepted because the results obtained appear to vary from one situation to another. There is the need for a formal comparison of the different approaches that have been used and the assumptions on which they are based in order to be able to understand the extent to which the variation in the results obtained is real or might be attributed to methodological differences. The present study used the ‘prime/intermittent-dose end-product’ approach over 18 h as a reference with which to compare the ‘single-dose end-product’ approach, with urine being collected for periods of 9 to 48 h. N flux was derived in a total of thirteen normal men using oral [15N]glycine and measurement of I5N enrichment in urinary NH3 or urea, with isotope being given either as prime/intermittent doses or a single dose in separate studies. The pattern of results was similar to those reported in the literature. In all studies the rates of N flux derived from urea were higher than those derived from NH3, under equivalent conditions, by about 25–30%. The single-dose approach, with urine collection over 9 h, gave results which were consistently higher than the prime/intermittent-dose approach. The extent of the difference was influenced by the duration of time over which the cumulative excretion of isotope in urine was determined, and with NH3 as the end-product the most consistent estimates of N flux could be obtained with a urine collection of at least 12 h and no greater than 24 h. With urea as the end-product, correction for the label retained in the body pool at 9 h gave similar results for N flux to those derived from the total excretion of label in urea over 24 h. The derivation of values for protein synthesis and protein degradation from measures of flux requires care to ensure that the time periods over which N intake and excretion are measured accord with those for which the measurement of flux apply. It is concluded that measurements of protein turnover similar to those obtained with the prime/intermittent-dose approach can be obtained with the single-dose approach in the fed state during the daytime, either from the excretion of label in urinary NH3 over a period of 12 h or with the excretion of label in urinary urea over a period of 24 h. The suitability of the method for use in the fasted state or at night time remains to be determined.

The aim was to compare the effect on atherogenesis of dietary monounsaturated and saturated fatty acids in cholesterol-clamped rabbits. To obtain an average plasma cholesterol concentration of 20 mmol/l in each rabbit during the 13-week cholesterol-feeding period, dietary cholesterol was adjusted weekly. The amount of fat fed daily was 10 g per rabbit in Expts A (n 23), C (n 36), and D (n 58) and 5 g per rabbit in Expt B (n 24). The source of monounsaturated fatty acids was olive oil in all four experiments. The source of saturated fatty acids was butter in Expt A, lard in Expt B, coconut oil in Expt C, and butter or lard in Expt D. Generally, olive oil-fed groups received more cholesterol and tended to have more cholesterol in VLDL and less in LDL compared with groups receiving saturated fat. Analysis of variance of the combined results of all four experiments showed that, in comparison with saturated fat, olive oil lowered aortic cholesterol by 13 (−9–30, 95% confidence interval) % in the aortic arch, and by 10 (−10–26) % in the thoracic aorta, which was not significant. In the comparison with olive oil, no differences in effects on aortic cholesterol content were detected between butter, lard and coconut oil. These findings do not support the view that replacement of dietary saturated fat with olive oil has a major impact on the development of atherosclerosis in addition to that accounted for by changes in plasma cholesterol levels.

To investigate the effect of dried Bacillus subtilis culture on growth, body composition and hepatic lipogenic enzyme activity, female broiler chicks were fed on either no additive (control) or dried B. subtills-culture-supplemented commercial diets (215 g crude protein/kg, 12.85 MJ metabolizable energy/kg) at 10 or 20 g/kg diet for 28 d from 14 to 42 d of age. Body weight, and moisture, fat, protein and ash contents of the body were not influenced by the B. subtilis culture. Feed efficiency. N utilization, the ratio of abdominal fat or liver to body weight, acetyl-coenzyme A carboxylase (EC 6·4·1·2) activity, liver and serum cholesterol contents were significantly lower in treatment groups, while fatty acid synthetase activity and serum cholesterol concentration were not significantly different, compared with the control group. Liver triacylglycerol concentration was decreased in chicks given 20 g culture·kg diet, while serum and carcass triacylglycerol concentrations were significantly lower in treatment groups than in the control group. Serum phospholipid concentration was increased but carcass phospholipid concentration was decreased in chicks given 20 g B. subtilis/kg diet, while liver phospholipid concentration was not significantly influenced. The advantages of inclusion of B. subtilis to the broiler diet included improved feed efficiency, less abdominal fat, reduced triacylglycerol concentrations in the liver, serum and carcass and reduced cholesterol concentrations in the liver and carcass.

Malnutrition in infancy is a global problem which leads to retardation of childhood growth and development. There is a pressing need to improve weaning strategies for infants of the developing world. Traditional Gambian weaning foods are watery and of low energy density, but addition of energy in the form of fat and carbohydrate leads to thick, viscous gruels which are difficult to ingest. Partial digestion with amylase (EC3·2·1·1)-rich flour reduces their viscosity while retaining their energy density. The aim of the present study was to measure the digestibility of a maize-based weaning food, before and after amylase digestion, in malnourished children using a 13C breath test. Ten children (aged 7–16 months; mean weight-for-age Z score −0·8) received isovolumetric and isoenergetic quantities of a maize-based weaning food naturally abundant with 13C. Breath samples were collected at intervals of 30 min for 5 h thereafter and 13CO2 enrichment was measured by isotope-ratio mass spectrometry. Percentage dose of 13C recovered increased from a mean 13·7 (SD 3·7)% before, to 18·3 (SD 5·6)% after ingestion of amylase-treated weaning foods (P < 0·1). There was a significant inverse relation between age and weight, and percentage dose of 13C recovered in children receiving amylase-treated feeds. There were no differences in concentrations of amylase in saliva of infants or breast milk of their mothers. Partial digestion of supplementary foods may improve the nutrition of undernourished weaning children, not only by reducing their viscosity, thereby increasing ingestion, but also by improving their digestion and thereby their absorption.

The present study was designed to determine the quantitative effects of starchy meals containing guar gum on rates of net apparent glucose absorption and net apparent insulin and gastric inhibitory polypeptide (GIP) production in growing pigs. The effects of these meals on the viscosity of jejunal digesta were also examined and correlated to changes in glucose absorption. Four growing pigs were each given either a low-fat semi-purified diet (control) or the same diet supplemented with a high-molecular-weight guar gum at concentrations in the diet of 20 or 40 g/kg. Blood samples were removed simultaneously via indwelling catheters from the mesenteric artery and the hepatic portal vein. Samples of jejunal digesta were removed via a T-piece cannula and used immediately for viscosity measurements at 39°. The ‘zero-shear’ viscosity of each sample was then calculated. Blood-flow measurements were made using an ultrasonic flow probe fitted to the hepatic portal vein. All measurements were made at intervals of 10 or 30 min during a 4 h postprandial period. Meals containing guar gum significantly increased (P < 0·05) the viscosity of jejunal digesta, an effect that was strongly dependent on the concentration of guar gum in the original diet. No significant differences in blood-flow rates were found between the control and guar-containing diets. Both concentrations of guar gum significantly reduced (P < 0·05) glucose absorption and insulin and GIP secretion rates over the 4 h postprandial period. An inverse relationship between the rate of glucose absorption and the ‘zero-shear’ viscosity of jejunal digesta was found. This study also provides direct evidence for the important role played by the entero-insular axis in modifying the glycaemic response to a meal containing guar gum.

A previous study has shown that malnourished, clinically stable patients with liver cirrhosis are in protein and energy balance at their spontaneous dietary intake and that an improvement in nutritional status cannot be anticipated at this intake (Nielsen et al. 1993). In the present study we examined to what extent oral intake could be increased by nutritional support, and to what extent dietary protein would be retained with increased intake. The techniques used for balance studies were also validated since this information is not available for patients with liver cirrhosis. Fifteen malnourished patients with alcoholic liver cirrhosis were given increasing amounts of a balanced ordinary diet for 38 (SE 3) d. Intakes of protein and energy were recorded by weighing servings and leftovers on food trays. Protein intake was calculated from food tables. Total N disposal was calculated after measurement of urinary N excretion, and protein balance was calculated from the N balance. A validation study of protein balance in a subgroup of patients (analysis of N in food by the duplicate portion technique, correction for incomplete recovery of urine by measurement of urinary para-aminobenzoic acid (PABA) after administration of PABA tablets, and measurement of faecal N) did not change protein balance values. Protein intake increased from 1. 0 (SE 0.1) g/kg per d to 1·8 (SE 0·1)g/kg per d. With increasing protein intake, 84 (SE 8)% of the increase in intake was retained. The rate of protein retention was not saturated at the intakes obtained in this study. Protein intolerance was only encountered in one patient. Available evidence indicates that the requirement for achieving N balance is increased in these patients but protein retention is highly efficient with increased intake. Protein retention is dependent on energy balance. Energy intake was calculated from food tables and total energy expenditure was calculated by the factorial method. A validation study was performed in a subgroup of patients. The energy contents of food sampled by the duplicate portion technique, and of urine and faeces were measured by bomb calorimetry. Resting energy expenditure (REE) was measured by indirect calorimetry before and at the end of the study, and O2 uptake during bicycle exercise was measured before and at the end of the study. The measured intake of metabolizable energy was on average 13% lower than the value given in food tables. Calculated energy expenditure was not changed by the validation study. Mean energy intake was 163 (SE 10) kJ/kg per d and mean energy expenditure was 134 (SE 5) kJ/kg per d (P = 0·007), indicating that the protein retention described occurred at a positive energy balance. It is concluded that a substantial retention of dietary protein can be obtained by oral nutrition support over a prolonged period of time in patients with liver cirrhosis. Requirements of protein for maintenance and repletion in these patients are discussed.

The effects of different amounts of the non-absorbable fat replacer sucrose polyester (SPE), water, and fat added to six warm preload lunches on feelings of appetite and food intake were investigated in two studies that were replicates of each other. In the first study thirty-nine subjects consumed rice preloads; in the second study thirty-five subjects consumed macaroni preloads. The six preloads were fixed on three energy levels: 1·8, 2·7, or 3·7MJ. At 2 h after preload consumption a test-meal buffet of thirty-one products was presented. Food intake was recorded on the study day, and the day after the study day. For women no energy compensation occurred in either study. Men showed a tendency to compensate for the energy differences between the preloads. However, when the fat of the preloads was replaced by SPE, energy compensation was less than 50% and non-significant. Statistically significant energy-compensation (66 %) was found when fat was replaced by water. No macronutrient-specific compensation occurred in men or women in either study. Lower total fat and energy intakes were found with the preloads where fat was replaced by SPE compared with the preloads containing fat. The appetite ratings were in line with the energy intake values, with no differences in women, and higher appetite ratings after the lower energy preloads in men. This short-term study indicates that SPE may be a useful aid to reduce fat and energy intakes.

To examine the hormonal effects of isoflavones, of which soyabean is a rich source, fifteen healthy non-vegetarian premenopausal women were studied over 9 months. They lived in a metabolic suite for between 4 and 6 months where their diet and activity levels were kept constant and their hormonal status was measured over two or three menstrual cycles. During one (control) menstrual cycle a normal but constant diet containing no soyabean products was fed. Then, over a second complete cycle six subjects consumed a similar diet into which 60 g textured vegetable protein (TVP)/d, containing 45 mg conjugated isoflavones, had been incorporated. Three participants had 50 g miso (a fermented soyabean paste), containing 25 mg unconjugated isoflavones, added daily to their diet over a menstrual cycle, and six others consumed 28 g TVP/d, containing 23 mg conjugated isoflavones. Five participants completed a third diet period where they were randomly assigned to consume either the control diet over a cycle, or a similar diet incorporating 60 g of a soyabean product which had had the isoflavones chemically extracted (Arcon F). Follicular phase length was significantly (P < 0·01) increased and peak progesterone concentrations were delayed with 60 g TVP but no effects were observed with Arcon F. The increase in menstrual cycle length did not reach statistical significance in the three subjects who ate 50 g miso/d, but peak progesterone levels were significantly (P < 0·05) delayed. Mid-cycle peaks of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were suppressed with 45 mg conjugated isoflavones as 60 g TVP (P < 0·05 and P < 0·01 respectively). No other changes in sex-steroid hormone levels were observed on any of the other diets. A significant reduction in total cholesterol was found with 45 mg conjugated isoflavones (P < 0·05), but not with 23 mg conjugated isoflavone-free Arcon F. There was no effect of menstrual cycle phase on transit time.