1. An alternative statistical technique, based on analysis of the 75th percentile, was used to examine teenagers' diets. The technique was developed to identify personal characteristics that affected the prevalence of high energy and nutrient intakes. It provided useful information not obtainable from methods based on average intakes.

2. The study sample was a representative sample of 1055 high-school students in Tasmania, Australia, aged 11–16 years.

3. Among girls, the prevalence of high intakes of energy and several nutrients was not affected by any of the fifteen characteristics studied. (In this context, ‘high’ was defined as above the 75th percentile for girls.) Fatter, heavier girls were less likely to have high intakes of carbohydrate, iron and niacin-equivalent, and also of meat and ‘empty-energy’ foods. Girls from small families were less likely to have high calcium intakes, and girls from goverment schools less likely to have high thiamin intakes.

4. Among boys, age generally had the greatest influence on the prevalence of high intakes (‘high’ being defined as above the 75th percentile for boys). Older boys were more likely to have high intakes of energy and most nutrients, as well as meat, cereals and fruit and vegetables. These age-related changes were, however, rather asynchronous. High fat intakes were more common among boys wbo had drunk more than five glasses of alcoholic beverages in the preceding week. High Ca intakes were more frequent among those who exercised vigorously, and high vitamin A intakes less common among the sons of well-educated mothers.

1. Albino rats were fed on diets containing 30, 120 or 200 g protein/kg with or without the incorporation of dichlorodiphenyltrichloroethane (DDT) or hexachlorocyclohexane (HCH) at 100 mg/kg diet for 4 weeks.

2. The activities of the liver microsomal enzymes NADPH-cytochrome reductase (EC 1.6.2.4), flavoprotein- linked monooxygenase (EC 1.14.14.1)and O-demethylase were significantly greater in animals fed on 120 and 200 g protein/kg diet compared with those fed on 30 g protein/kg diet.

3. The inclusion of DDT or HCH at all protein intakes led to further significant rises in microsomal enzyme activities but the increases were much greater for animals receiving the 120 and 200 g protein/kg diets than for those receiving the 30 g protein/kg diet.

4. The results imply that detoxification of DDT or HCH was carried out more effectively at the higher protein intakes.

1. The impact of frame-size categories in weight-height tables was studied by comparing the efficiency of the body-mass index (weight/height2 (W/H2)) and weight adjusted for body-height and a body-diameter, W/(H2Dp), in predicting body fatness.

2. Body-weight, body-height, six body-diameters and four skinfold thicknesses were measured in ninety-five men and seventy women, aged between 23 and 35 years. Percentage of body fat was calculated from skinfold thicknesses using regression equations according to Durnin & Womersley (1974).

3. The inclusion of a body-diameter increased the explained variation of body fatness from 57% to 62% (knee) and 63% (shoulder) in men and from 63% to 69% (knee) in women.

4. It can be concluded that in the present population the efficiency of the prediction of percentage of body fat was not improved markedly by the inclusion of a body-diameter in the body-mass index, thus giving no support for the inclusion of frame-size categories in weight-height tables.

1. Sixty marasmic children were investigated for the absorption of xylose, proteins and fats. Their duodenal juice samples were also analysed for bile salts and microflora.

2. The marasmic children were then studied in three groups of twenty by allocating them to three different dietary schedules: a high-protein diet (30% of the total energy from protein), a high-fat diet (40% of the total energy from fat) and a high-carbohydrate diet (70% of the total energy from carbohydrate) for 2 weeks and the previous measurements repeated.

3. Whereas the high-fat diet resulted in improved fat absorption, along with an increase in total and conjugated bile acids, and the high-carbohydrate diet led to improved xylose absorption, the diet rich in protein resulted in an improvement in the absorption of all three dietary ingredients. It appears that a high-protein diet improves the overall absorption process by improving the intestinal environment as a whole, while high-carbohydrate and high-fat diets bring about adaptive changes related to the respective absorptive processes.

1. A weaning food commonly used in Nigeria was simulated by mixing processed sorghum (Sorghum bicolor) with skim-milk powder (830: 170, w/w).

2. Replacing 310 g/kg sorghum with processed cowpeas (Vigna unguiculata) resulted in an increase in protein content from 96 to 113 g/kg and an increase in biological value of the protein from 0.74 to 0.87.

3. The two mixtures were compared with an established commercial baby food by a panel of Nigerian mothers and all three foods were found to be equally acceptable.

4. Processing the cowpeas by pressure cooking followed by roller-drying reduced the trypsin-inhibitor content to minimum levels.

5. It is concluded that the protein content and quality of the weaning mixture popularly used in Nigeria could be improved by partially replacing the sorghum with cowpeas.

1. The effect of chronic alcohol intoxication on metabolic disturbances and fatty infiltration and degeneration was studied in genetically obese, hyperlipoproteinaemic, fa/fa Zucker rats.

2. Sixteen obese Zucker (fa/fa) rats, sixteen lean Zucker rats (Fa/-)and sixteen Wistar rats, all male rats aged 7–8 weeks, were given either a control (C)diet (13% of energy from protein, 37% from fat, 50% from carbohydrate) or an ethanol (E) diet (13% of energy from protein, 37% from fat, 14% from carbohydrate, 36% from ethanol) for 4 weeks.

3. The fa/fa rats given diet E consumed more energy than those given diet C, but after 4 weeks the weight gains and degrees of obesity were similar for both groups. With both diets, the developed hyperlipidaemia could be explained by the hyperinsulinaemia. Both hypertriglyceridaemia and hypercholesterolaemia were lower in fa/fa rats eating diet E than in those given diet C. Fatty infiltration of the liver, as assessed by hepatic triacylglycerol and cholesterol contents, was observed with both diets, but for fa/fa rats it was less extreme in those given diet E.

1. The proteins binding retinol, and retinol concentrations, were determined in amniotic fluid, placental cytosol and in the fetal and maternal circulation.

2. In non-pregnant women, plasma retinol was almost exclusively found in a transthyretin-retinol-binding-protein complex whereas, in pregnant women, retinol-binding-protein-bound retinol was observed not complexed to transthyretin. This latter fraction increased in concentration with fetal age. These two fractions were the major retinol-protein complexes in amniotic fluid and their relative amounts changed with progress of gestation.

3. In fetal blood both of these fractions were again found, with higher proportions of retinol-binding- protein-bound retinol in the umbilical artery than in the umbilical vein.

1. Sixteen obese (fa/fa) Zucker rats, sixteen lean (Fa/-)Zucker rats and sixteen Wistar rats, all male rats aged 7–8 weeks, were given either a control (C) diet containing no ethanol or an ethanol (E) diet in which 36% of the energy was supplied by ethanol, for a period of 4 weeks.

2. The activities of glucose-6-phosphate dehydrogenase (EC 1.1.1.49), glucose-6-phosphatase (EC 3.1.3.9) and glycerol kinase (EC 2.7.1.30) and the glycogen content in the livers of obese (fa/fa)rats were lower in animals given diet E than in those given diet C. As a result, hepatic lipogenesis and fatty degeneration of the liver were reduced in obese (fa/fa) rats given diet E.

1. The availability of iron, zinc and calcium in a diet containing 400 g ‘fibre-filler’ (a mixture of bran, fruit and nuts, used in the F-plan diet)/kg diet (HF diet) was measured by whole-body counting in rats, using 59Fe, 66Zn and 47Ca as extrinsic labels, and compared with a diet of similar mineral content but no ‘fibre-filler’ (LF diet). Absorption of Fe and Ca was significantly higher from the HF than from the LF diet but there was no difference in Zn availability between the two diets.

2. The ability of rats given LF or HF diets for 3 or 28 d to absorb Fe, Zn and Ca was measured using ferrous sulphate, zinc chloride and calcium chloride in a cooked starch-sucrose (1: 1 w/w) paste, extrinsically-labelled with the appropriate isotope. There was no difference in Fe absorption between the HF- and LF-fed groups but both Zn and Ca absorption were higher in LF- than in HF-fed animals after 3 and 28 d.

3. The mineral status of the animals given HF or LF diets for 28 d was examined, and there were no differences in blood haemoglobin, liver and bone Zn and plasma and bone Ca levels. The total liver Fe was significantly lower (P < 0.05) in the HF-fed animals.

4. It was concluded that ‘fibre-filler’did not have an adverse effect on Fe, Zn or Ca metabolism in rats although the long-term effect on Fe status warrants more detailed investigation. Further work is required to extend these studies to man.

1. In a previous study (Kindt et al. 1983, 1984) it was assumed that a protein hydrolysate, devoid of phenylalanine, together with intact protein as given to children with phenylketonuria (PKU), was equivalent to egg or milk protein. One group of children was given this ‘PKU protein’ in amounts corresponding to the Joint FAO/WHO ad hoc Expert Committee (1973) recommendations. The results indicated that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of protein intake were marginal.

2. The purpose of the present study was to evaluate whether the quality of the protein hydrolysate, together with intact protein (‘PKU protein’), is equivalent to egg or milk protein. This was done using a rat bioassay. Four protein sources were used: (1) egg protein, (2) protein hydrolysate, (3) protein hydrolysate diluted with non-essential amino acids, (4) protein hydrolysate mixed with food proteins (‘PKU protein’), comparable with the diet previously used (Kindt et al. 1983, 1984).

3. The results indicated that the ‘PKU protein’ was of very high qua1ity: net protein utilization (NPU) > 90. The protein hydrolysate alone and the protein hydrolysate diluted with non-essential amino acids gave a NPU > 80.

4. The conclusion drawn from the present study is that the ‘PKU protein’, as used in the treatment of children with PKU, is equivalent to egg or milk protein. This supported the view that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of intake were marginal.

1. The claims that rats fed on diets with ‘brown sugar’ (unrefined muscovado) perform better in a number of ways than do rats fed on refined white sugar (sucrose) have been examined.

2. Male Wistar rats were fed on purified diets from weaning, in which the carbohydrate component was either maize starch or unrefined sugar or sucrose. The sugars produced no differences in growth rate, body composition, or the weights of liver or kidneys. Compared with sucrose, unrefined sugar produced an increase in blood cholesterol and in the activity of hepatic fatty acid synthetase, and a greater increase in blood triglyceride. In confirmation of earlier results, rats fed on either sugar had heavier livers and kidneys, increased activity of hepatic glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and a higher concentration of plasma triglyceride compared with rats fed on maize starch.

3. Female Sprague-Dawley rats were fed on the same three diets as the male rats, and mated when they weighed about 200 g. No difference was seen in their ability to mate, the progress of pregnancies, or the sizes of the litters. Does fed on unrefined sugar produced litters of higher viability than did does fed on starch or sucrose. Survival was between 85 and 100% with unrefined sugar and between 30 and 75% with starch or sucrose.

4. Unrefined muscovado sugar has thus been shown to contain a factor required by female rats for the proper viability of their pups. This may be the same ‘Reproductive Factor R’ as that described by Wiesner & Yudkin (1951). In certain circumstances, unrefined muscovado sugar might therefore contribute to the nutritional value of a human diet, although in what circumstances, in what respect and to what extent it might do so, is by no means clear.

1. Groups of rats were given a fibre-free diet containing none or one of the three fibre components: pectin, cellulose or galactomannan.

2. After feeding for 16 weeks, total protein level and β-glucuronidase (EC 3.2.1.31) activity in the contents and mucosa of jejunum and ileum, and in the contents only of the caecum, were determined.

3. The pectin supplement reduced protein concentration in jejunal contents while cellulose reduced protein concentration in the ileal and caecal contents.

4. β-Glucuronidase activity of caecal contents was significantly reduced in both the pectin- and cellulose-fed groups.

5. Cellulose affected the β-glucuronidase activity of both the ileal contents while pectin reduced the β-glucuronidase of the ileal but not the jejunal contents.

6. Dietary fibre components did not significantly affect jejunal or ileal mucosal β-glucuronidase activity.

1. Diets containing isolated soya-bean protein induce lower levels of serum cholesterol in animals than diets containing casein. Experiments were conducted to investigate whether differences in digestibility of the proteins might explain this effect.

2. At pH 8 with pancreatic enzymes or intestinal peptidase, soya-bean protein was hydrolysed in vitro much less rapidly than casein. However, with pepsin (EC 3. 4. 23. 1) at acid pH, soya-bean protein was hydrolysed more rapidly than casein.

3. These differences in digestibility may be due to pH-dependent changes in solubility of the proteins. Casein and soya-bean protein were most soluble at alkaline and acid pH respectively.

4. Heat treatment of the proteins resulted in lower solubilities and digestibilities. Sonication of soya-bean protein at pH 7.8 increased solubility but only slightly raised digestibility.

5. When fed to rabbits, enzymically hydrolysed soya-bean protein induced a 2.3-fold higher concentration of serum cholesterol than did intact soya-bean protein. The hypocholesterolaemic effect of soya-bean protein may be partly attributable to its low solubility and digestibility at alkaline pH.

1. The present study was designed to use the factorial approach to estimate protein requirements of Nigerian male adults by measuring obligatory nitrogen losses via urine, faeces and sweat when N intake was very low and energy intake adequate.

2. Eight adult men from Osegere village near Ibadan and seven medical students from the University of Ibadan, who volunteered to participate as subjects in the study, were given a low-protein diet (based on staple foods habitually consumed by subjects) for 10 d. Mean daily total protein intake was 4.68 g while that of energy was 0.2 MJ/kg body-weight. After an initial 5 d adaptation period, 24 h urine and faeces were collected in marked containers for five consecutive days for N determination. N losses from the skin were also determined in the village adults.

3. Mean daily urinary, faecal and sweat N losses (mg N/kg body-weight) were 45.88 (SD 4.84), 21.79 (SD4.19), and 7.46 (SD1.71) from the village adults. The corresponding urinary and faecal N losses from the university students were 43.45 (SD 2.28) and 18.32 (SD4.66) (sweat N loss not measured). Thus the total daily obligatory N losses (per kg body-weight) from the village adults and university students were 75.13 and 69.23 mg N respectively (assuming a sweat N loss of 7.46 mg for the university students). After adjusting for requirement and making a 30% allowance for individual variability, the safe level of protein intake was calculated to be 0.78 and 0.73 g protein/kg body-weight for the village men and university students respectively.

4. These values suggest that the Joint FAO/WHO ad hoc Expert Committee (1973) safe allowance of 0.57 g egg protein/kg per d is not sufficient for most young adults in this environment when energy intake is adequate.

1. A low-iodine diet consisting of maize, peas (Pisum sativum), torula yeast, meat meal, maize oil and added vitamins, minerals and amino acids was given to eight pairs of adult, common cotton-eared marmosets (Caliithrix jacchus jacchus). Eight control pairs were given the same diet to which potassium iodate was added. Both groups also received low-I apple and deionized water.

2. The diet provided adequate nutrition, as confirmed by the maintenance of body-weight and good health.

3. In the I-deficient marmosets the concentration of plasma thyroxine was decreased from 140.1 nmol/l to 22.4 nmol/l and thyroid-stimulating hormone increased significantly from 1.8 ng/ml to 9.0 ng/ml compared with control marmosets, thereby indicating severe I deficiency.

4. Compared with newborn offspring from control marmosets, the thyroid glands from the I-deficient offspring showed (a) an increase in weight, (b) a decrease in I content and (c), on histological examination, hyperplasia, hypertrophy and a total absence of colloid material in the follicles.

1. Six growing pigs (30–75 kg) were fed on semi-purified diets containing either 30 g maize oil/kg diet (LFM), 30 g soya-bean oil-tallow mixture (1:1, w/w)/kg diet (LFST) or 160 g soya-bean oil-tallow mixture (1:1, ww)/kg diet (HFST) without and with the addition of guar gum (40g/kg diet).

2. Plasma glucose and insulin concentrations following twice daily feeding at 09.00 and 21.00 h were measured, during 24 h periods, in blood sampled from a permanent indwelling vena cava catheter.

3. The source and level of dietary fat had no significant effect on pre-prandial plasma glucose or insulin concentrations except for insulin with diet LFST in the morning (P<0.05). Addition of guar gum to the diets had no significant effect on pre-prandial plasma glucose and insulin levels.

4. The peak post-prandial plasma glucose and insulin levels were not significantly affected by dietary fat. The addition of guar gum, however, significantly reduced (P < 0.05) the peak post-prandial plasma glucose concentration with diets LFM and LFST and also the peak plasma insulin concentration for all diets except for diet HFST in the morning.

5. The time taken to reach the peak post-prandial plasma glucose and insulin concentrations was not significantly affected by dietary fat but it was increased by the addition of guar gum, although the differences were not always significant.

1. Estimates of nutrient intakes based on food purchasing records modelled on the National Food Survey (NFS) were compared with nutrient intakes calculated from food consumption records based on a semi-weighed method, a combination of weighing and household measurement techniques. Of eighty-two families in Cambridge who completed the study, thirty-two were volunteers and fifty were from a random sample in which the co-operation rate was 73%.

2. The estimated energy and nutrient contents of the Cambridge food purchases were very similar to those reported by the NFS for families of similar composition and income. The energy intakes obtained by the semi-weighed method were compared with results from twenty-five studies of energy intake based on quantitative measurements of food consumption: there was no evidence to suggest that the semi-weighed method consistently under- or overestimated intakes in the Cambridge subjects.

3. Purchases adjusted to allow for waste and consumption of food by visitors contained significantly more energy, protein, carbohydrate, calcium, iron and dietary fibre than measured home food consumption. There was no significant difference in the nutrient content of purchases and consumption per 4.184 MJ (1000 kcal), with the exception of Fe and ascorbic acid.

4. Measured wastage of edible food in thirty-one families averaged 3.2% of purchases. Estimate of wastage in all eighty-two families was 3.8%, and consumption of food by visitors accounted for 3.0% of purchases.

5. The excess of purchases over measured home food energy intake is probably accounted for by a net increase in larder stocks rather than wastage, consumption of food by visitors, or under-recording of intakes.

1. The effect of nutrition on the incidence of pancreatic damage was studied. Injection of excess arginine was found to cause more massive necrosis of the acinar cells after 24 h in malnourished rats (those given 50 g casein/kg diet) than in well-nourished rats (those given 200 g casein/kg diet).

2. Ultrastructural examination showed that whorl formation of the endoplasmic reticulum, decreases in the number of zymogen granules and formation of vacuoles in the cytoplasm were more marked in rats given 50 g casein/kg diet. Degradation of zymogen granules within vacuoles in the damaged cells was frequently observed in rats given 200 g casein/kg diet.

3. Necrosis of adipose tissue was associated with pancreatic damage more frequently in rats given 200 g casein/kg diet; rats with large amounts of zymogen granules in the acinar cells showed particularly severe necrosis of adipose tissue. Rats given 50 g casein/kg diet did not show necrosis of adipose tissue.

4. These results indicate that in the malnourished state there were more marked arginine lesions of the pancreas in which to study cellular and histologic changes than in the well-nourished state and that the occurrence of necrosis of adipose tissue may be related to a high content of zymogen granules in the acinar cells before pancreatic damage.