Severe malnutrition is widely distributed throughout the world, showing a high prevalence in developing countries. Experimental animal models have been useful to study the effects of malnutrition at different levels and ages. Apoptosis is a well recognised process of cell death occurring under several physiological and pathological conditions. It represents the principal mechanism involved in cell selection in the thymus. Thymocyte apoptosis induction by dexamethasone is one of the best characterised experimental models of programmed cell death. The aim of the present study was to determine whether severe malnutrition increased spontaneous and/or dexamethasone-induced apoptosis in vivo in thymocytes of experimentally malnourished rats during lactation. Thymocytes were obtained from malnourished rats at weaning (21d of age). Apoptosis frequency was estimated by the terminal transferase-mediated dUTP nick end labelling assay. Spontaneous apoptosis was 1·9 (SD 1·0) % IN WELL NOURISHED RATS IN CONTRAST TO 13·3 (sd 3·8) % in malnourished animals; this is seven times greater (P<0·001). Interestingly, the frequency of dexamethasone-induced apoptosis was similar in both groups of animals (47·9 (sd 10·1) % in well nourished rats and 53·8 (sd 8·0) % in malnourished rats). The results obtained in the present study indicate that malnutrition is associated with a significant increase of spontaneously apoptotic cells. In addition, the data showed that the fraction of thymocytes susceptible to dexamethasone-induced apoptosis was similar in well nourished and malnourished animals. The greater levels of spontaneously apoptotic cells associated with malnutrition could be related to alterations of the microenvironment of the thymus and/or to an obstruction of early thymocyte maturation.

One of the objectives of the present study was to investigate whether 1 % conjugated linoleic acid (CLA) in the diet reduced tumour incidence in the colon of 1,2-dimethylhydrazine (DMH)-treated rats. Colon cancer was induced by injecting 6-week-old, male, Sprague–Dawley rats with 15 mg/kg DMH twice per week for 6 weeks. They were fed either 1 % CLA or a control diet ad libitum for 30 weeks. Dietary CLA significantly decreased colon tumour incidence (P<0·05). Our second objective was to investigate whether apoptosis in the colon mucosa of DMH-treated rats was affected by the amount of dietary CLA and whether the changes in apoptosis were related to those in fatty acid-responsive biomarkers. For this purpose, rats were killed after being fed a diet containing 0 %, 0·5 %, 1 % or 1·5 % CLA for 14 weeks. CLA was undetected in the mucosa of rats fed the 0 % CLA diet and increased to 5·9 mg/g phospholipid in rats fed the 0·5 % diet. The apoptotic index estimated by the terminal deoxynucleotidyl transferase-mediated dUTP nick and labelling technique was increased by 251 % and the 1,2-diacylglycerol content was decreased by 57 % in rats fed 0·5 % CLA. No further changes in these variables were observed when CLA in the diet was raised to 1·0 % or 1·5 %. However, dietary CLA decreased mucosal levels of prostaglandin E2, thromboxane B2 and arachidonic acid in a dose-dependent manner. The present data indicate that dietary CLA can inhibit DMH-induced colon carcinogenesis by mechanisms probably involving increased apoptosis.

It has been suggested that the current dietary recommendations (low-fat–high-carbohydrate diet) may promote the intake of sugar and highly refined starches which could have adverse effects on the metabolic risk profile. We have investigated the short-term (6-d) nutritional and metabolic effects of an ad libitum low-glycaemic index–low-fat–high-protein diet (prepared according to the Montignac method) compared with the American Heart Association (AHA) phase I diet consumed ad libitum as well as with a pair-fed session consisting of the same daily energy intake as the former but with the same macronutrient composition as the AHA phase I diet. Twelve overweight men (BMI 33·0 (SD 3·5) KG/M2) WITHOUT OTHER DISEASES WERE INVOLVED IN THREE EXPERIMENTAL CONDITIONS WITH A MINIMAL WASHOUT PERIOD OF 2 WEEKS SEPARATING EACH INTERVENTION. BY PROTOCOL DESIGN, THE FIRST TWO CONDITIONS WERE ADMINISTERED RANDOMLY WHEREAS THE PAIR-FED SESSION HAD TO BE ADMINISTERED LAST. DURING THE AD LIBITUM VERSION OF THE AHA DIET, SUBJECTS CONSUMED 11695·0 (sd 1163·0) kJ/d and this diet induced a 28 % increase in plasma triacylglycerol levels (1·77 (sd 0·79) v. 2·27 (sd 0·92) mmol/l, P<0·05) and a 10 % reduction in plasma HDL-cholesterol concentrations (0·92 (sd 0·16) v. 0·83 (sd 0·09) mmol/l, P<0·01) which contributed to a significant increase in cholesterol:HDL-cholesterol ratio (P<0·05), this lipid index being commonly used to assess the risk of coronary heart disease. In contrast, the low-glycaemic index–low-fat–high-protein diet consumed ad libitum resulted in a spontaneous 25 % decrease (P<0·001) in total energy intake which averaged 8815·0 (sd 738·0) kJ/d. As opposed to the AHA diet, the low-glycaemic index–low-fat–high-protein diet produced a substantial decrease (-35 %) in plasma triacylglycerol levels (2·00 (sd 0·83) v. 1·31 (sd 0·38) mmol/l, P<0·0005), a significant increase (+1·6 %) in LDL peak particle diameter (251 (sd 5) v. 255 (sd 5) Å, P<0·02) and marked decreases in plasma insulin levels measured either in the fasting state, over daytime and following a 75 g oral glucose load. During the pair-fed session, in which subjects were exposed to a diet with the same macronutrient composition as the AHA diet but restricted to the same energy intake as during the low-glycaemic index–low-fat–high-protein diet, there was a trend for a decrease in plasma HDL-cholesterol levels which contributed to the significant increase in cholesterol:HDL-cholesterol ratio noted with this condition. Furthermore, a marked increase in hunger (P<0·0002) and a significant decrease in satiety (P<0·007) were also noted with this energy-restricted diet. Finally, favourable changes in the metabolic risk profile noted with the ad libitum consumption of the low-glycaemic index–low-fat–high-protein diet (decreases in triacyglycerols, lack of increase in cholesterol:HDL-cholesterol ratio, increase in LDL particle size) were significantly different from the response of these variables to the AHA phase I diet. Thus, a low-glycaemic index–low-fat–high-protein content diet may have unique beneficial effects compared with the conventional AHA diet for the treatment of the atherogenic metabolic risk profile of abdominally obese patients. However, the present study was a short-term intervention and additional trials are clearly needed to document the long-term efficacy of this dietary approach with regard to compliance and effects on the metabolic risk profile.

The effects of 12 weeks of antioxidant supplementation on exercise-induced oxidative stress were investigated in older adults (60 (SE 1) YEARS; BMI 26 (se 1) kg/m2). Subjects were randomly divided in two groups: supplementation (n 11) with 100 mg dl-α-tocopheryl acetate, 200 mg ascorbic acid, and 2 mg β-carotene, and placebo (n 9). Before and after the 12 week supplementation period, subjects cycled for 45 min at submaximal intensity (50 % maximal workload capacity). Antipyrine was used as marker for oxidative stress. Antipyrine reacts quickly with hydroxyl radicals to form para- and ortho-hydroxyantipyrine. The latter metabolite is not formed in man through the mono-oxygenase pathway of cytochrome P450. Daily supplementation significantly increased plasma concentrations of α-tocopherol and β-carotene in the supplemented group (Δ 14·4 (se 3·2) and 0·4 (se 0·1) μmol/l; P<0·001 and P<0·01). No significant differences, within and between groups, were observed in the exercise-induced increase in the ratios para- and ortho-hydroxyantipyrine to antipyrine. In addition, supplementation did not affect the exercise-induced increase in thiobarbituric acid reactive substances in plasma. In conclusion, in 60-year-old subjects antioxidant supplementation had no effect on the exercise-induced increase in oxidative stress as measured by free radical products of antipyrine.

It has been suggested that protein synthesis in peripheral tissues: (1) responds in a curvilinear manner to increasing feed intake over a wide range of feeding levels; and (2) has a greater sensitivity to intake than protein breakdown. The aim of the present experiment was to test these hypotheses across the ovine hindlimb. Six growing sheep (6–8 months, 30–35 kg), with catheters in the aorta (two), posterior vena cava and jugular vein, received each of four intakes of dried grass pellets (0·5, 1·0, 1·5 and 2·5×maintenance energy; M) for a minimum of 7 d. A U-13C-labelled algal hydrolysate was infused intravenously for 10 h and from 3–9 h para-aminohippuric acid was infused to measure plasma flow. Arterial and venous plasma were obtained over the last 4 h and the concentrations and enrichments of thirteen 13C-labelled amino acids (AA) were determined by GC–MS. As intake increased, a positive linear response was found for plasma flow, arterial concentrations of the aromatic and branched-chain AA, total flow of all AA into the hindquarters and net mass balance across the hindquarters (except glycine and alanine). Based on two separate statistical analyses, the data for protein synthesis showed a significant linear effect with intake (except for phenylalanine, glycine and alanine). No significant curvilinear effect was found, which tends not to support hypothesis 1. Nonetheless, protein synthesis was not significantly different between 0·5, 1·0 and 1·5×M and thus the 2·5×M intake level was largely responsible for the linear relationship found. There was no significant response in protein breakdown to intake, which supports hypothesis 2.

The effects of increasing levels of Fe on serum fatty acids, cholesterol, triacylglycerol, liver and heart were examined in male Sprague–Dawley rats fed either Fe-deficient or carbonyl Fe-supplemented diets with 35 (control), 350, 3500 and 20 000 μg Fe/g for 12 weeks. As intake of Fe increased, serum total cholesterol increased from 2·0 mmol/l in controls to 5·2 mmol/l at the highest level of Fe. Also, the total serum phospholipid fatty acids increased from 609 mg/dl in controls to 1292 mg/l at the highest level of Fe. Except for the highest dose of Fe, the ratio of saturated to unsaturated phospholipid fatty acids increased from 1·2 to 1·7. The serum total free fatty acid levels remained constant among all groups with a range from 162 to 228 mg/l, while a ratio of 0·6 to 0·8 for saturated to unsaturated fatty acids was maintained. A dose-related increase in liver non-haem Fe from 18 to 3500 μg/g correlated with increases in lipid peroxidation (r 0·87), measured by the lipid-conjugated diene assay. Oxidative changes in the liver may have resulted in alterations in sterol synthesis, leading to increased serum cholesterol levels with increases in serum phospholipids and changes in the ratios of their saturated to unsaturated fatty acids. Animals with heart damage showed myocardial degeneration and cardiomyopathy with haemosiderin in interstitial macrophages or myocardial fibres and, when these were coupled with the findings of increased non-haem Fe in the heart and lipid peroxidation in the liver, suggested that oxidative stress is involved in the pathogenesis of the lesions.

The aim of this present study was to identify the earliest point at which riboflavin deficiency affects post-weaning bowel development in rats. After weaning, eighty Wistar rats were weight-matched as pairs, one animal being fed a normal synthetic diet and the other being fed the same diet but deficient in riboflavin. Body weight, feeding and rates of growth were monitored and eight pairs of animals were taken for analysis at 45, 69, 93, 117 and 141 h. Riboflavin status was monitored by determining the erythrocyte glutathione reductase activation coefficient (EGRAC), and hepatic flavins were measured by a fluorescence assay. Changes to the number and dimensions of villi and crypts in the duodenum were determined, as well as crypt division (bifurcation) and the DNA synthesis index of the crypt epithelium by bromodeoxyuridine (BrdU) labelling. Riboflavin deficiency was established in the experimental rats, as demonstrated by a significant increase in EGRAC after 45 h (P<0·001) and decreased liver flavins after 96 h (P<0·001). After 96 h a significant increase in the size and cellularity of the crypts (P<0·001 in both cases) was seen in these riboflavin-deficient animals, with a decreased incidence of bifurcating crypts and of BrdU-labelled cells. No changes to villus number or size were observed. The present study has demonstrated that developmental changes to the duodenal crypt arise shortly after circulating riboflavin measurements show evidence of deficiency. These changes primarily affect cell proliferation and crypt bifurcation, and precede long-term changes such as the reduction of villus number.

The accuracy of the multiple pass 24 h recall for assessment of habitual energy intake in pre-school children is unclear. The primary aim of this study was to assess its accuracy by comparison with measurement of total energy expenditure by doubly-labelled water in a representative sample of forty-one 3–4-year-olds. The recall method was well tolerated by subjects and was administered quickly and easily. However, it produced estimates of energy intake which significantly exceeded measures of total energy expenditure from doubly-labelled water, mean paired difference 660 kJ/d (P<0·01). Agreement between the two methods was poor at the individual level: limits of agreement 660+/-3018 kJ/d. Error and imprecision in both methods contribute to individual differences, but the present study suggests that the multiple pass 24 h recall does not provide accurate estimates of dietary energy intake in individual children.

Many Indonesian infants have an inadequate nutritional status, which may be due in part to inadequate maternal nutrition during pregnancy. This study was designed to investigate whether infant nutritional status could be improved by maternal vitamin A and Fe supplementation during gestation. Mothers of these infants from five villages had been randomly assigned on an individual basis, supervised and double-blind, to receive supplementation once weekly from approximately 18 weeks of pregnancy until delivery. Supplementation comprised 120 mg Fe and 500 μg folic acid with or without 4800 retinol equivalent vitamin A. Mothers of infants from four other villages who participated in the national Fe and folic acid supplementation programme were also recruited; intake of tablets was not supervised. Anthropometric and biochemical parameters of infants and their mothers were assessed approximately 4 months after delivery. Infants of mothers supplemented with vitamin A plus Fe had higher serum retinol concentrations than infants of mothers supplemented with Fe alone. However, the proportion of infants with serum retinol concentrations <0·70 μmol/l was >70 % in all groups. Maternal and infant serum retinol concentrations were correlated. Fe status, weight and length of infants were similar in all groups. Fe status of girls was better than that of boys, but boys were heavier and longer. We conclude that supplementation with vitamin A in conjunction with Fe supplementation of women during pregnancy benefits vitamin A status of their infants. However, considering the large proportion of infants with marginal serum retinol concentrations, it may still be necessary to increase their vitamin A intake.

The fatty acid composition and lipid content of white muscle, liver and mesenteric fat, in reared v. wild sharpsnout sea bream (Diplodus puntazzo) were compared. The mesenteric fat index (100×mesenteric fat weight/body weight) and the lipid contents of both white muscle and liver proved consistently higher in farmed v. wild sharpsnout sea bream (79·0 (SE 13·1) V. 38·7 (se 5·1) g/kg, 188·4 (se 30·0) v. 58·2 (se 3·9) g/kg and 27·2 (se 3·7) v. 17·3 (se 1·9) g/kg, respectively). The higher values of linoleic, eicosapentaenoic, docosahexaenoic and n-3 series acids in reared fish muscle make reared sharpsnout more favourable for human consumption. In reared fish mesenteric fat, polyunsaturated fatty acids reached higher levels (32·54 (se 0·71) g/100 g total fatty acids than those found in wild fish (26·08 (se 1·38) g/100 g total fatty acids or even present in the diet (28·34 g/100 g total fatty acids). Compared with cultured fish, wild sharpsnout displayed a higher content of n-3 fatty acids in liver fat (31·67 (se 1·13) g/100 g total fatty acids), but lower in mesenteric fat (20·35 (se 1·41) g/100 g total fatty acids). Atherogenic index values were similar for wild and reared fish in all tissues, while the index of thrombogenicity of muscle and mesenteric fat (0·353 (se 0·012) and 0·402 (se 0·021) respectively) was significantly increased in wild fish probably due to the omnivorous habits of the species and/or to seasonal food variations. Depending on the time of the year or the season, reared fish could be more suitable for human consumption than wild fish.

A study was undertaken to examine the effect of different dietary carnitine (200 and 1000 mg/kg diet) and fat (90 and 190 g/kg diet) supplementation on growth and fatty acid concentrations of fish fed either with a low- (13 g/kg) or a high-lysine (21 g/kg) diet. African catfish (22·7 g/fish), Clarias gariepinus Burchell, juveniles were stocked (sixteen aquaria, twenty-five fish per aquarium) and fed for a maximum of 74 d. Dietary lysine had a clear effect on growth performance and feed conversion ratios, but dietary carnitine supplements had no effect. High-carnitine supplements increased total carnitine content (P<0·0004) and reduced tissue free carnitine: acyl-carnitine ratio (P<0·05) compared with low-carnitine supplements. High-fat supplements decreased liver carnitine concentrations. Clear effects on liver fatty acid concentrations were observed in high-carnitine-fed fish compared with low-carnitine-fed fish. The primary liver fatty acids affected were 18:2n-6 (linoleic acid), 20:5n-3 (eicosapentanoic acid) and 22:6n-3 (docosahexanoic acid). The whole-body fatty acid balance suggested that 20:5n-3 disappeared (apparently by β-oxidation) more readily than 18:2n-6 and/or 22:6n-3. From 774 mg 20:5n-3 eaten by high-lysine–high-fat–low-carnitine fish, 58 % was not assimilated into body tissues. High-carnitine-fed fish showed an increase in 20:5n-3 oxidation by 7 % compared with low-carnitine fish. Although dietary carnitine did not improve body growth, these results support the hypothesis that carnitine can enhance the mobilisation of long-chain fatty acids towards oxidation.