Skinfold thicknesses represent a comparatively simple and reasonably accurate assessment of body fatness which is an important part of the estimation of nutritional state. However, much emphasis is placed on the necessity to be very precise in the exact position of the skinfold being measured and there is frequently concern, also, about the variability of the measurement by different observers using different types of caliper. Fifty-three women and forty-five men had four skinfolds (biceps, triceps, supra-iliac and subscapular) measured first at the standard sites (Tanner, 1953; Edwards et al. 1955), and then at deliberately chosen sites about 20 mm distant from the ‘correct’ ones. The effect on the estimation of body fatness by this manoeuvre resulted in a difference of usually less then 1% and, at a maximum, 3%. In the light of the uncertainty of the basic assumptions which are made in extrapolating from skinfolds (or indeed densitometry, total body water, total body K, and others) to body fatness, these technical errors assume comparatively little importance.

Available anthropometric reference values for elderly people do not include specific norms for over-90-year-old subjects despite their increasing number. In the present study, weight, height and a number of anthropometric variables related to body muscle and fat mass were collected from fifty-seven nonagenarian and forty-one centenarian healthy, non-institutionalized subjects living in an Italian area. Recumbent anthropometry was used to avoid errors associated with impaired mobility. Nonagenarians and centenarian men were taller and heavier than women of corresponding age and had a greater amount of muscle and trunk fat, whereas women showed a marked peripheral adipose distribution. Anthropometric values of both age-groups were generally lower than published norms for 70–89-year-old American and European elderly people. However, differences were less marked when comparing Italian nonagenarians and centenarians with French and British people aged 85 years and over than when comparing Italian subjects with American octogenarians and younger European elderly people. Taken together these findings suggest a dramatic loss of muscle and fat mass in over-90-year-old subjects with respect to younger elderly people. However, changes between successive generations and geographical influences cannot be excluded. The need for local and age-specific norms in nutritional assessment of over-90-year-old people is emphasized. It is also suggested that current anthropometric indices may not be reliable when evaluating the oldest elderly subjects.

HDL-phospholipids are determinants in reverse cholesterol transport. They are mostly derived from triacylglycerol (TG)-rich lipoproteins. Chylomicron size is important, therefore, because it is related to the ratio surface phospholipids: core TG and, thus, determines the availability of postprandial phospholipids for transfer to HDL. Eleven healthy young women each ingested four different fat loads supplemented with retinyl palmitate and containing 60 g sunflower oil (SO), oleic–sunflower oil (OSO), mixed oil (MO; (g/kg) linoleic acid 480, oleic acid 380, linolenic acid 13) or beef tallow (BT). At the peak of TG absorption for all loads (4 h) chylomicron diameters, determined by agarose-gel filtration, were larger after SO compared with OSO (P < 0·05) and BT (P = 0·06) and after MO compared with BT (P < 0·05). At 6 h chylomicron size was larger after the vegetable oils compared with BT (P < 0·05 in each case). After each fat load chylomicron size decreased at 6 and 8 h compared with that at 4 h (P < 0·05) except for OSO. Retinyl ester and TG concentrations were lower in chylomicrons after BT than after the other fats but not in the chylomicron-free serum (containing chylomicron remnants), suggesting absorption in the form of very small particles. Compared with the fasting value, the concentration of the Svedberg unit of flotation 20–400 fraction, which contains VLDL and chylomicron remnants, was lower 8 h after MO, the only fat to contain significant amounts of linolenic acid. We conclude that chylomicron size is dependent on the fatty acid composition of ingested fats and the time-course of digestion, being larger for polyunsaturated fatty acid-rich fats and in the early phase of digestion. On the basis of retinyl ester concentration there were no differences between fats in chylomicron-remnant clearance.

The physiological effects of dietary fibres in humans are due to their physico-chemical properties. However, it is difficult to predict these effects simply by measuring certain characteristics in vitro. Studies in human subjects are still required to assess the effectiveness of new substrates. The aim of the present study in healthy human subjects was to evaluate the effects of two novel fibres, potato (PF) and maize (MF), on fasting and postprandial blood concentrations of carbohydrate and lipid metabolites as well as on stool ouput and transit time. The chemical composition, water-binding capacity (WBC) and fermentative properties of the fibres were also characterized in order to determine their possible involvement in digestive and metabolic effects. Stools, as well as breath and blood samples, were collected after consumption for 1 month of either a basal diet (control) or a basal diet supplemented with fibre (15 g/d). MF resisted fermentation better than PF and had lower digestibility. However, both fibres increased faecal output of dry matter, neutral sugars and water. There was an inverse relationship between stool weight and orofaecal transit time, although only MF significantly reduced transit time. Orocaecal transit was lengthened by PF, probably because of its high WBC. PF ingestion also decreased postprandial plasma levels of total and esterified cholesterol but had no effect on fasting concentrations. In contrast, MF lowered fasting cholesterolaemia and increased free:esterified cholesterol. These particular physiological and fermentative properties suggest that PF and MF would be suitable ingredients in a healthy diet.

While many studies show reduced work output in heavy labour with poor nutritional status, data among less-physically-strenuous industrial occupations is scarce. In the present study the output of ninety-two women jute-factory workers over a 1-month period was measured together with haemoglobin, BMI, arm muscle and fat area, physical work capacity (maximum O2 consumption; ), as well as socio-economic, health and activity variables. A significant correlation was found between haemoglobin and work output, which remained significant (P < 0·005) after a multipleregression analysis with other potentially confounding factors. Anaemic workers and those with values less than 1·5 1/min were significantly less active at home than non-anaemic workers (P < 0·015). Anaemic women produced an average of 5·3% less in the factory and performed an average of 6·5 h less housework per week.

Although the role of vitamin C in common cold incidence had been studied extensively, the level of vitamin C intake has not been unequivocally shown to affect the incidence of colds. In the present study the six largest vitamin C supplementation (≥ 1 g/d) studies, including over 5000 episodes in all, have been analysed, and it is shown that common cold incidence is not reduced in the vitamin C-supplemented groups compared with the placebo groups (pooled rate ratio (RR) 0·99; 95% CI 0·93, 1·04). Consequently these six major studies give no evidence that high-dose vitamin C supplementation decreases common cold incidence in ordinary people. Nevertheless, the analysis was continued with the hypothesis that vitamin C intake may affect common cold susceptibility in specific groups of people. It was assumed that the potential effect of supplementation might be most conspicuous in subjects with low dietary vitamin C intake. The average vitamin C intake has been rather low in the UK and plasma vitamin C concentrations are in general lower in males than in females. In four studies with British females vitamin C supplementation had no marked effect on common cold incidence (pooled RR 0·95; 95% CI 0·86, 1·04). However, in four studies with British male schoolchildren and students a statistically highly significant reduction in common cold incidence was found in groups supplemented with vitamin C (pooled RR 0·70; 95% CI 0·60, 0·81). Thus, these studies with British males indicate that vitamin C intake has physiological effects on susceptibility to common cold infections, although the effect seems quantitatively meaningful only in limited groups of people and is not very large.

The energy expenditure of six goats averaging 35 (SE 0·3) kg was measured when the animals were standing or walking on a treadmill enclosed in a confinement-type respiration chamber at different speeds (0·167, 0·333 and 0·500 m/s) and slopes ( — 10, — 5, 0, +5 and +10%). The energy costs of locomotion, estimated from the coefficients of linear regressions of heat production (HP) per kg body weight v. distance travelled were 1·91, 2·33, 3·35, 4·68 and 6·44 J/kg BW per m for — 10, — 5, 0, +5 and +10% inclines respectively, indicating that the energy expenditure of walking over standing changes with slope according to a slightly curvilinear relationship. The energy cost of raising 1 kg body weight one vertical metre was found to be 31·7 J, giving an average efficiency for upslope locomotion of 30·9%. The energy recovered on vertical descent was estimated as 13·2 J/kg per m, indicating an efficiency of the energy recovered above the theoretical maximum.

The disappearance of total N, non-protein-N and amino acid-N after washing, rumen incubation and intestinal passage of sugarbeet pulp, maize-gluten feed, maize feed meal, palm kernel meal, soyabean hulls, soyabean meal, grass silage, maize silage and concentrate was measured in four dairy cows using nylon-bag techniques. Disappearance of amino acid-N after washing varied between feedstuff's from 14 to 69% of feed amino acid-N, and was lower than disappearance of non-protein-N. For sugarbeet pulp, grass silage and maize silage, washing had a considerable effect on the amino acid profile. Disappearance of amino acid-N after rumen incubation was also lower than non-protein-N and varied between feedstuffs from 25 to 73% of feed amino acid-N. Rumen incubation had only a small effect on the amino acid profile of the residue after washing. Disappearance of amino acid-N in the intestine varied between feedstuffs from 70 to 99% of rumen undegraded amino acid-N, and was higher than the disappearance of non-protein-N. Intestinal incubation showed a considerable effect on the amino acid profile for all feedstuffs. It was concluded that protein that was assumed to escape rumen degradation and was absorbable in the intestine was higher in amino acids and methionine, and lower in non-amino acid-N and glutamic acid and proline compared with protein in the feedstuff.

In the present study energy balance and liver respiratory activity were studied in rats fed on either a control diet or an energy-dense diet. Liver respiration was assessed both without added substrates and after the addition of hexanoate, glycerol, or sorbitol. The effect of ouabain on hexanoate-supported respiration was also determined. Metabolizable energy intake and energy expenditure increased in rats fed on an energy dense diet, but body-weight gain, as well as lipid and protein content, remained unchanged. When net energy expenditure, obtained excluding the total cost of storage, was expressed as a percentage of metabolizable energy, significant differences were found between the two groups of rats. This finding supports the presence of regulatory mechanisms in rats fed on an energy-dense diet, which are useful to counteract development of obesity. In addition, a significant increase in liver respiratory activity was found in rats fed on an energy-dense diet, both in the basal state and in that stimulated by added substrates. Na/K-pump-dependent O2 consumption also increased in rats fed on an energy-dense diet. The results indicate that a greater production of metabolic heat by the liver can contribute to the increased energy expenditure found in rats fed on an energy-dense diet.

The activities of hepatic enzymes of fatty acid synthesis and oxidation were compared in rats fed on diacylglycerol and triacylglycerol. In the first trial, rats were fed on diacylglycerol or triacylglycerol (rapeseed oil) for 14 d. The diacylglycerol preparation contained 65·2 g and 32·6 g fatty acids/100 g total fatty acids as 1,3-species and 1,2-species respectively. Fatty acid compositions of these dietary lipids were similar. Dietary acylglycerols were added to experimental diets to provide the same amounts of fatty acids (93·9 g/kg diet). Dietary diacylglycerol compared with triacylglycerol significantly reduced the concentrations of serum and liver triacylglycerol. The activities of enzymes of fatty acid synthesis (fatty acid synthetase, glucose 6-phosphate dehydrogenase (EC 1.1.1.49) and malic enzyme (EC 1.1.1.40)) were significantly lower in rats fed on diacylglycerol than in those fed on triacylglycerol. In contrast, the rates of mitochondrial and peroxisomal oxidation of palmitoyl-CoA in liver homogenates were higher in rats fed on diacylglycerol than in those fed on triacylglycerol. In the second trial, varying amounts of dietary triacylglycerol were replaced by diacylglycerol while the dietary fatty acid content was maintained (93·9 g/kg diet). After 21 d of the feeding period the significant reductions in serum and liver triacylglycerol levels were confirmed in groups of rats fed on the diets in which diacylglycerol supplied more than 65·8 g fatty acids/kg diet (65·8 and 93·9 g/kg). Reductions in the activities of enzymes of fatty acid synthesis and increases in palmitoyl-CoA oxidation rates by both mitochondrial and peroxisomal pathways were also apparent when diacylglycerol replaced triacylglycerol in diets to supply more than 65·8 g fatty acid/kg. Increasing dietary levels of diacylglycerol also progressively increased the activities of enzymes involved in the β-oxidation pathway (carnitine palmitoyltransferase (EC 2.3.1.21), acyl-CoA dehydrogenase (EC 1.3.99.3), acyl-CoA oxidase (EC 1.3.3.6), enoyl-CoA hydratase (EC 4.2.1.17), 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35), 2,4-dienoyl-CoA reductase (EC 1.3.1.34) and Δ3,Δ2-enoyl-CoA isomerase (EC 5.3.3.8)) in the liver. These results suggest that alteration of fatty acid metabolism in the liver is a factor responsible for the serum triacylglycerol-lowering effect of dietary diacylglycerol.

We studied Fe absorption from FeSO4 in rats with Fe deficiency-induced anaemia that were given an Fe-sufficient purified diet without or with ascorbic acid (10·4 g/kg diet). Attention was focused on mucosal Fe uptake as measured in vivo by a double-isotope technique. Haemoglobin repletion and liver Fe levels were not affected when the ascorbic acid-supplemented diet was given, but apparent Fe absorption and retention of orally administered 59Fe were significantly enhanced. The distribution of Fe between liquid and solid phases of contents of both the stomach and the proximal intestine was not affected by the feeding of the ascorbic acid, but ascorbic acid significantly enhanced mucosal Fe uptake. It is concluded that ascorbic acid in the diet raises mucosal Fe uptake through a mechanism independent of the intestinal Fe solubility.

The efficiency with which β-carotene protects against oxidative stress in chicken embryo fibrobiasts (CEF) at low O2 partial pressures was assessed. Primary cultures of CEF were grown at low O2 partial pressures and oxidatively stressed by exposure to paraquat (PQ). Activities of the antioxidant enzymes superoxide dismutase (EC 1.15.1.1; SOD), catalase (EC 1.11.1.6; CAT) and glutathione peroxidase (EC 1.11.1.9; GSH-Px) were measured as indices of oxidative stress. CEF incubated with 0·25–1·0 mM—PQ for 18 h exhibited increased SOD and CAT activities compared with non-PQ-treated control cells (P < 0·001). No cytotoxicity as indicated by lactate dehydrogenase (EC 1.1.1.27; LDH) release was observed at PQ concentrations below 2·0 mM. Incorporation of added β-carotene into 0·25 mM-PQ-treated cells prevented the PQ-induced increases in SOD and CAT, and activities were similar to those seen in non-PQ-treated control cells. GSH-Px activity decreased relative to its control value on exposure to 0·25 mM-PQ and β-carotene prevented this decrease in a dose-dependent manner. The proportion of LDH released from the CEF treated with β-carotene remained below the control value of 2·5% at all times.

In work aimed at developing methodologies for validation of estimates of the dietary intake of free-living individuals, Bingham and colleagues have examined the use of urinary nitrogen (UN) excretion as an index of protein intake (Bingham & Cummings, 1985; Bingham, 1994; Bingham et al. 1995). The basis of this approach is that in subjects in N equilibrium, N intake is assumed equal to N excretion. Thus, if N excretion is measured it should indicate N and dietary protein intakes. In practice, since most N excretion occurs via the urine, which is relatively simple to collect, Bingham and colleagues examined the relationship between 24 h UN and N intake (DN). They argued that in subjects on typical UK diets UN should bear a fixed relationship to DN, and measured it carefully in a group of subjects. They showed that in a group of eight individuals in which intake and N excretion were measured meticulously, UN was 81% DN (SD 2, range 78–83%). They argued that measurement of this ratio could be used to assess the validity of food intake measurement and concluded ‘In healthy individuals eating normal western diets, 24 h urine N from an 8 day collection verified for its completeness by the PABA check method, should establish urine N to within 81(SD 5)% of the habitual dietary intake, range 70–90%. If the dietary assessment from 18 days of records or 24 h recalls or the diet history falls within these limits, it can be stated that there is no evidence of interference with normal dietary habits, or of reporting errors….’ (Bingham & Cummings, 1985).