1. When nineteen ‘free-living’ male students, who normally ate 231 (SEM 14) g white bread/d changed to wholemeal bread for a 19-week period, there was no significant change in body-weight, plasma cholesterol or plasma triglyceride levels. These values, as well as plasma concentrations of calcium, phosphate, urate and haemoglobin, remained essentially the same as those for a control group.

2. Increasing the wheat-fibre intake by eating wholemeal bread is not an effective method for reducing blood lipid levels, at least in healthy young men with a moderate bread intake.

1. The long-term fate of an oral dose of [75Se]selenomethionine was studied in four women.

2. Urinary and faecal excretion, respiratory losses and whole-body retention of 75Se were measured, and also 75Se turnover in whole body, plasma and erythrocytes during a period of 33–44 weeks.

3. Intestinal absorption of [75Se]selenomethionine by the four subjects was 95.5–97.3% of the administered dose.

4. Urinary excretion accounted for 6–9% of absorbed 75Se in the first 2 weeks. No radioactivity was detected in expired air.

5. After the initial 8 weeks during which radioactivity decreased more rapidly, whole-body retention of 75Se decreased exponentially with a half-time of 207–290 d.

6. Plasma 75Se concentration reached a maximum level 3–4 h after the dose. Transient initial uptake of 75Se in erythrocytes during the first hour was followed by a gradual increase to a maximum concentration at 8–12 weeks.

7. These results are compared with the results of an earlier study of the metabolism of [75Se]selenite in two of the same women. 75Se from [75Se]selenomethionine was found to be more completely absorbed, had a greater retention and smaller endogenous urinary and faecal losses than 75Se from [75Se]selenite, and these differences persisted throughout the experimental period. These findings differed from those obtained in rats in which, after an initial period, 75Se from selenite was metabolized similarly to that from selenomethionine.

1. The effect of increasing dietary protein content on the amount of faecal nitrogen was measured in six normal subjects and five subjects without functioning colons (three with ileostomy and two with ileo-rectal anastomosis).

2. There was a significant increase in the amount of faecal N with increased dietary protein content in the subjects without functioning colons.

3. In normal subjects with intact colons, faecal N content was found to be lower than that in subjects without colons, and furthermore there was no significant variation with diet.

4. The source of the increase in faecal N with increased dietary protein content in subjects without functioning colons is discussed and the significance of these findings in relation to the efficiency of protein absorption is considered.

1. A study has been made by gel filtration techniques of the soluble copper-and zinc-binding proteins in livers from pigs of different Zn status..

2. The distribution of both Cu and Zn between the three fractions isolated was greatly influenced by the Zn status of the animal. In livers from pigs given a Zn-supplemented diet the proportion of either Cu or Zn found in the fraction with a molecular weight of about 12000 (fraction 3) was a direct function of the total liver concentration of the metal. In livers from pigs given a low-Zn diet, only small amounts of Cu or Zn were present in this fraction, regardless of liver Cu content..

3. These results suggest that Zn may be essential for the stabilization of the metal-binding protein in this fraction.

1. Studies have been made with solvent-extracted chicken muscle, bovine plasma albumin (BPA) and other proteins, all severely heated in the absence of carbohydrates so as to cause a large decrease in their fluorodinitrobenzene (FDNB)-reactive lysine contents.

2. ɛ-N-(β-L-aspartyl)-L-lysine and ɛ-N-(γ-L-glutamyl)-L-lysine isopeptides were determined after enzymic digestion of heated chicken muscle, and their content was found to increase as the material was subjected to more heat treatment. Heated chicken muscle was not found to contain lanthionine. Heated BPA, on the other hand, was found to contain lanthionine but not the isopeptides. Both lanthionine and isopeptide cross-linkages were detected in most of the other heated proteins. There was some difficulty in quantifying the amounts of isopeptides formed on heat treatment, because the enzymic digestion procedure used in their isolation appeared to be incomplete. Neither lysinoalanine nor ornithinoalanine was detected in any of the test materials.

3. The severely heated chicken muscle was fed to rats, and ileal and faecal digestibilities were studied. Protein digestibility was found to be greatly reduced after heat treatment, although the isopeptides themselves appeared to be at least as digestible as the total N component, total lysine, or FDNB-reactive lysine. However, the reduction in ileal N digestibility only partly accounted for the much larger reduction in nutritive value, as measured by net protein ratio ((weight loss of N-free animals + weight gain of test animals) ÷ weight of crude protein (N × 6.25) consumed by test animals). Possible reasons for this are discussed.

1. Diets containing different proportions of skim milk and fat, either beef tallow or soya-bean oil, supplemented with fat-soluble vitamins were given to 2-d-old pigs. Each fat source was used in three diets containing approximately 280, 350 and 420 g fat, and 260, 235 and 210 g protein/kg dry matter respectively..

2. The diets were given as a milk containing 200 g solids/l during a 26 d experiment. The pigs were given the diet at hourly intervals according to a scale based on live weight..

3. Increasing the energy content of the diet, with the accompanying decrease in protein content, had no effect on live-weight gain or feed: gain ratio (g feed dry matter/g live-weight gain) (other than a slight reduction in live-weight gain when beef tallow was used), or on nitrogen retention. However, the fat content of the carcass of the 28-d-old pig was increased, and its protein and ash content were decreased..

4. The apparent digestibilities of the fatty acid ranged from 0.96 to 1.00. The faeces from pigs given the soya-bean-oil diets contained some eicosanoic, docosanoic and tetracosanoic acids, presumably of bacterial origin. In general, palmitic and stearic acids were slightly less well digested than oleic and linoleic acids.

1. A control diet and diets containing 150 g non-irradiated or 150 g irradiated mangopulp/kg were given to female rats from day 15 of the gestation period until weaning in trials 1 and 2, and from 40 d before mating until 28 d post weaning in trial 3.

2. Food intake and dry-matter digestibility were similar with all diets.

3. There were no significant differences between animals given the different dietary regimens in the daily body-weight changes of weanling males, pups, nursing females or females during the immediate postlactation period.

4. No differences in haematological or blood chemistry values were found which could be attributed to the ingestion of irradiated mangoes. There was no evidence for the presence of any toxic substances in the irradiated-mango-pulp diet.

5. Gross pathological observations revealed no aberrations which could be related to the ingestion of irradiated mangoes.

6. It may be concluded that the wholesomeness of mangoes was not affected by gammairradiation at a dose of 75 krd.

1. Thiamin, riboflavin and pyridoxine status of ‘low-income-group’ mothers and their newborn infants was assessed by analysing paired samples of maternal and umbilical cord blood for erythrocyte transketolase (EC 2.2.1.1) (ETK), erythrocyte glutathione reductase (EC 1.6.4.2) (EGR), and erythrocyte aspartate aminotransferase (EC 2.6.1.1) (EAA) activities..

2. The vitamin status of the infants was better than that of the mothers..

3. Most of the mothers and some of the infants had biochemical evidence of thiamin and riboflavin defciency..

4. The pregnant women had a higher EAA activity and also higher stimulation with pyridoxal-5-phosphate than the non-pregnant women of the same community..

5. There was a significant correlation between maternal and umblical blood samples for ETK and EGR activities, but not for EAA activity or any of the coenzyme stimulation tests.

1. The solubility of fatty acids in aqueous media containing bile salts alone and in admixture with either lecithin (phosphatidylcholine) or phosphatidylethanolamine was determined.

2. Over the pH range 2.0–7.4, the order of fatty acid solubility in aqueous solutions containing bile salts was linoleic > oleic > elaidic > palmitic > stearic. The solubility of each fatty acid increased as the pH of the micellar solution increased.

3. Addition of lecithin to aqueous solutions of bile salts greatly increased the solubility of palmitic acid and stearic acid.

4. In the presence of bile salts and lecithin, the solubility of oleic acid and elaidic acid decreased with increasing pH of the micellar solution, indicating a competitive effect between the fatty acid anions and lecithin. The solubility of linoleic acid increased linearly with lecithin concentration.

5. Phosphatidylethanolamine as an additive to bile salts increased the solubility of both saturated and unsaturated fatty acids in the pH range 2.0–7.4. The effectiveness of phosphatidylethanolamine as an amphiphile was similar to that of lecithin, although at pH 3.0 fatty acid solubility was greater in the presence of phosphatidylethanolamine.

6. The significance of these findings is discussed in relation to the intestinal absorption of fatty acids in sheep.

1. Electromyographical studies were made on the motility of the stomach and small intestine of five pigs when given a standard diet either ad lib., or as one or two meals/d. Recordings were made from electrodes placed chronically on the antrum, the duodenum and the jejuno-ileum, and a continuous 24 h recording was made every 2 d for a period of 4 weeks. A simple ‘T’-shaped cannula was positioned in the proximal duodenum in two of the pigs.

2. The basic pattern of activity of the small intestine was grouped in phases of irregular and regular activity characteristic of the myoelectric complex. This pattern recurred about eighteen times/d in fasting pigs, or in animals fed ad lib. and so eating frequent but small meals. When a myoelectric complex on the duodenum reached its regular ‘spiking’ phase, antral activity and passage of digesta ceased completely for a period (5–15 min) which varied according to the time elasped since the last meal.

3. In animals receiving one meal/d a postprandial pattern of activity lasted about 6 h. The proximal part of the intestine showed continuous activity with vigorous isolated or peristaltic spike bursts. The average number of myoelectric complexes was thirteen/d. When receiving two meals/d the postprandial pattern lasted for only 2–3 h, and approximately sixteen myoelectric complexes/d were recorded.

4. It is concluded that the extent of disruption of the basic intestinal motility pattern depends on the amount of food consumed per meal and subsequent release of nutrients.

1. The solubility of fatty acids in aqueous solutions containing bile salts and lysolecithin at pH values between 2.0 and 7.4 was studied. Both the 1-acyl and 2-acyl isomers of lysolecithin increased the solubility of fatty acids to the same extent, the order of solubility being linoleic > oleic > elaidic > palmitic > stearic.

2. The influence of the products of phospholipolysis of lecithin on palmitic acid solubility was determined. On a molar basis, lysolecithin was more effective than were bile salts in promoting the solubilization of the fatty acid.

3. In bile salt solutions in which the phospholipid concentration was constant on a molar basis, the solubility of palmitic acid decreased linearly with the progressive replacement of lecithin by lysolecithin. Palmitic acid was solubilized to the same extent on replacing lecithin with lysolecithin on a constant weight basis.

4. In bile salt solution containing lysolecithin and oleic acid in equimolar amounts, the solubility of palmitic acid was similar to that in bile salt solutions containing lecithin in equivalent proportion.

5. The results are discussed in relation to the action of phospholipolytic activity on the intestinal absorption of fatty acids in sheep.

1. Feeding sheep a concentrate diet compared with grass diets increased the hepatic specific activities of the three glycolytic enzymes studied, and that of glucose-6-phosphate dehydrogenase (EC 1.1.1.49), and reduced the specific activity of D-fructose-1,6-diphosphate 1-phosphohydrolase (EC 3.1.3.11). The specific activities of phosphogluconate dehydrogenase (EC 1.1.1.43) and malate dehydrogenase (decarboxylating) (NADP) (EC 1.1.1.40) were unaffected by diet.

1. The effect on protein quality of treating a commercial rat diet by autoclaving at various temperatures for different periods of time, or by irradiation with 2.5 or 10 Mrd, was studied. True digestibility (TD) and biological value (BV) were measured and the available and total amino acids in the diets were estimated using microbiological and chemical methods..

2. Autoclaving at 121° for 60 min reduced BV, TD and net protein utilization (NPU) more than autoclaving at 134° for 3 min. Availability of amino acids was reduced by both treatments but to a greater extent by autoclaving at 121° for 60 min. Total amino acids were essentially unaffected. Irradiation had no effect on BV, TD, NPU or total amino acids, and the availability of amino acids was also unaffected, with the exception of lysine which was slightly reduced..

3. When the diet was autoclaved at 115 or 121° for 15, 30 or 60 min, or at 134° for 3 min the availability of the amino acids was reduced with increasing time and temperature of treatment. Treatment at 134° for 3 min had an effect on available amino acids similar to treatment at 121° for 15 or 30 min..

4. Ethylene oxide fumigation of the diet caused reduced availability of histidine, methionine and tryptophan but had negligible effect on arginine, leucine and lysine..

5. It is concluded that from a practical point of view irradiation causes least damage to proteins in rodent diets. If such diets are to be autoclaved they should be supplemented with complete protein to counteract amino acid destruction.

1. The effect of consuming the same total amount of food in either one large meal or several small meals per d was studied using weanling male rats.

2. The increase in total body-weight was the same in both instances, but the weights of the liver, kidneys, femur, small intestine and stomach were greater, and those of the spleen and residual carcass were smaller, in meal-eating rats than in continuously fed control animals. These differences persisted into the adult state.

3. No differences in gross chemical composition were found between the corresponding organs of the two groups of rats, and the differences in weight appeared to be the result of changes in the general growth rate of individual organs.

4. The hypertrophy of the kidneys in meal-eaters was due to an increase in mean cell size, but the increased weight of the liver and reduced weight of the spleen appeared to be largely the result of changes in the number of cells present.

1. The observation that thyroid C cell hyperplasia occurred in rats given the iron-deficient diet described by McCall, Newman, O'Brien, Valberg & Witts (1962) prompted a closer study of the preparation and constituents of this diet..

2. It became apparent that there was a discrepancy between the amounts of fat-soluble vitamins in the dietary formulation reported and the supposed final content of the diet. A diet prepared as described by McCall et al. (1962) contains 1000 μg (40000 i.u.) ergocalciferol and 10 μg (14 500 i.u.) retinyl palmitate/kg..

3. An experiment was designed to study the effect of Fe-deficient and Fe-supplemented, high-vitamin-D diets, and an Fe-supplemented, normal-vitamin-D diet, on thyroid C cell volume and serum calcium concentration..

4. Thyroid C cell volumes and serum Ca concentrations were significantly higher in both groups given excess vitamin D than in the group given the Fe-supplemented, normal-vitamin-D diet. It is evident therefore, that hypervitaminosis D was the cause of the morphological and biochemical changes found in rats given the McCall et al. (1962) diet.

1. The thermic effect of a glucose load (50 g) was studied in ten control and eleven obese female subjects, using both direct and indirect calorimetry simultaneously. Experiments were done under conditions of thermal equilibrium (28° and 30% relative humidity)..

2. Thermal balance (heat production measured by indirect calorimetry minus heat losses measured directly) was negative in the control group during the fasting period (heat deficit – 14.2 ± 5.0 kJ/m2 per h), whereas that of the obese group was in equilibrium (+ 1.4 ± 4.8 kJ/m2 per h)..

3. After the glucose load, metabolic rate increased 13.0 ± 1.5 and 5.2 ± 1.3% in the control and obese groups respectively..

4. In contrast to the metabolic rate, total heat losses were not significantly altered in either group after the glucose load. Total heat losses of the obese group were significantly lower than those of the control group throughout the experimental period..

5. During the experiments the amount of heat stored was increased in both groups. Thermal balance in the control group became positive while that of the obese group remained positive..

6. During the fasting period, the control subjects oxidized more carbohydrates (90.4 mg/min) than lipids (68.8 mg/min), whereas obese subjects oxidized more lipids (103.7 mg/min) than carbohydrates (50.2 mg/min). After the glucose load, the oxidation rate of carbohydrates was increased in both groups to 158.1 mg/min in control subjects and 95.6 mg/min in obese subjects..

7. The mean skin temperature of the control subjects was significantly higher than that of the obese subjects and remained higher throughout the postprandial period..

8. These results indicate that: (a) during the fasting period, the energy sources utilized and the thermal balance of the two groups were different; (b) the thermic effect of glucose was less in the obese subjects and, therefore, might be a factor contributing to their low energy expenditure.

1. Ninety-one families containing 140 children under 4 years of age at enrolment were studied. At 1-monthly intervals, the children were weighed and measured and qualitative information about feeding habits was obtained. Weighed dietary surveys for periods of 5 d were made at approximately 8 months, 20 months, 3 years and 5 years of age; there were forty-six failures in 260 surveys attempted.

2. At the four specified ages, mean energy intakes were 3.75, 5.03, 5.82 and 6.75 MJ (896, 1203, 1392 and 1613 kcal)/d respectively. At 8 months, milk products provided on average, 43% of the total energy intake and commercial baby foods provided 17%. These values decreased to 21 and 2% respectively at 20 months and there was little further change thereafter.

3. Average intakes of energy and of most nutrients met recommended intakes (Department of Health and Social Security, 1969). Iron intakes were marginal, and vitamin D intakes were low.

4. The energy intake of boys was significantly higher than that of girls at 3 years of age, but the boys were not significantly heavier. The energy intake of children from ‘manualworker’ families was higher than that from ‘non-manual’ families. Similarly, the energy intake of children from larger families was higher than that of children from smaller families.

5. Energy intakes were correlated with body-weights and with rates of gain in weight. Irrespective of body-weight, ‘big eaters’ at 20 months tended to be ‘big eaters’ at 3 years also.

1. A number of rumen bacteria isolated because of their ability to deacylate phosphatidyl-choline, were found, in addition, to hydrogenate polyunsaturated fatty acids..

2. The most active lipolytic organisms had an unusual pattern of hydrogenation of dietary fatty acids in that α-linolenic acid was hydrogenated only as far as trans-11,cis-15-octadeca-dienoic acid.