Both intake of whole grain and higher levels of serum enterolactone have been related to reduced risk for CHD and some cancers. Because lignans are prevalent in the outer layers of grains, these findings may be related. We carried out a crossover feeding study in which overweight, hyperinsulinaemic, non-diabetic men (n 5) and women (n 6) ate, in random order, wholegrain foods or refined-grain foods in a diet with 30% energy from fat. The dominant whole grain was wheat, followed by oats and rice. All food was supplied by the investigators and each diet lasted for 6 weeks, with an intervening washout period of 6–9 weeks. Serum enterolactone concentrations were higher when eating the wholegrain than the refined-grain diet by 6·2 (within person SE 1·7) nmol/l (P=0·0008). Most of the increase in serum enterolactone when eating the wholegrain diet occurred within 2 weeks, though the serum enterolactone difference between wholegrain and refined-grain diets continued to increase through 6 weeks. Serum enterolactone concentrations can be raised by eating a diet rich in whole grains.

The aim of the present study was to compare Fe absorption from industrially-manufactured and home-cooked cereal foods. Fe absorption was measured using the radiolabelled Fe extrinsic tag technique in thirty-nine adult human subjects from cereal porridges manufactured by extrusion cooking or roller-drying, and from the same cereal flours after home cooking to produce pancakes, chappattis or bread. One series of cereal porridges was amylase-treated in addition before roller-drying. Fe absorption was relatively low from all products, ranging from 1·8–5·5% for rice, 2·5–3·5% for maize, 4·9–13·6 % for low-extraction wheat, and <1% for high-extraction wheat foods. The phytic acid content remained high after drying of the cereal porridges being about 1·20, 1·70, 3·20, 3·30 mg/g in low-extraction wheat, rice, high-extraction wheat and maize products respectively, and could explain the low Fe absorption. There were little or no differences in Fe absorption between the extruded and roller-dried cereals, although amylase pre-treatment increased Fe absorption from the roller-dried rice cereal 3-fold. This was not due to phytate degradation but possibly because of the more liquid nature of the cereal meal as fed. There were similarly few or no differences in Fe absorption between the industrially-processed cereals and home-cooked cereals made into pancakes or chappattis. Bread-making, however, degraded phytic acid to zero in the low-extraction wheat flour and Fe absorption increased to 13·6%, the greatest from all cereal foods tested. It is concluded that Fe absorption from extruded, roller-dried or home-cooked cereal foods is similarly low and that only those cooking procedures such as bread-making, which extensively degrades phytic acid, or amylase pre-treatment, which substantially liquifies cereal porridges, improve Fe absorption.

The present study investigated metabolic responses to fat and carbohydrate ingestion in lean male individuals consuming an habitual diet high or low in fat. Twelve high-fat phenotypes (HF) and twelve low-fat phenotypes (LF) participated in the study. Energy intake and macronutrient intake variables were assessed using a food frequency questionnaire. Resting (RMR) and postprandial metabolic rate and substrate oxidation (respiratory quotient; RQ) were measured by indirect calorimetry. HF had a significantly higher RMR and higher resting heart rate than LF. These variables remained higher in HF following the macronutrient challenge. In all subjects the carbohydrate load increased metabolic rate and heart rate significantly more than the fat load. Fat oxidation (indicated by a low RQ) was significantly higher in HF than in LF following the fat load; the ability to oxidise a high carbohydrate load did not differ between the groups. Lean male subjects consuming a diet high in fat were associated with increased energy expenditure at rest and a relatively higher fat oxidation in response to a high fat load; these observations may be partly responsible for maintaining energy balance on a high-fat (high-energy) diet. In contrast, a low consumer of fat is associated with relatively lower energy expenditure at rest and lower fat oxidation, which has implications for weight gain if high-fat foods or meals are periodically introduced to the diet.

The work presented here examines the possible effects of nutritional deficiencies on the characteristics of the plasma transport protein for vitamin D and its metabolites (vitamin D binding protein, DBP) in the growing rat. Deficiencies in both dietary protein intake and dietary energy intake may decrease the concentration of DBP in the circulation, although plasma DBP was not affected by dietary Ca deficiency. None of the dietary factors examined appears to influence the affinity of DBP for its major ligand, 25-hydroxycholecalciferol (25(OH)D3). Protein-deficient rats seemed to have difficulty in maintaining adequate concentrations of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) in the circulation. The sensitivity of DBP to dietary protein and energy intake may constitute a novel mechanism that may help to explain the observed associations between malnutrition and the development of metabolic bone disease, through alterations to the cellular availability of vitamin D ligands to DBP.

Studies in the Gambia, using the lactulose–mannitol dual-sugar intestinal permeability test (lactulose:mannitol ratio) as a non-invasive way of investigating mucosal damage, have shown that food malabsorption is significantly associated with early growth retardation. In this cross-sectional study, 210 poor urban Nepali children, 0–60 months old, were recruited and measured for height or length and weight, 167 were examined for intestinal permeability and 173 for parasite infection. Weaning and morbidity data were collected from 172 caretakers. Children were mildly stunted (mean height-for-age Z-score −1·45) and underweight (mean weight-for-age Z-score −1·62). The lactulose:mannitol ratio (0·26) was poorer than that of UK children (0·12), but similar to that found in Bengali children of the same age (0·24). Two stages of weaning, the onset supplementary feeding (6 months) and the cessation of breast-feeding (23 months), were shown to have differential impact. In children currently breast-feeding, the duration of supplementation was negatively related to lactose (P<0·001) and lactose:lactulose values (P<0·0001), indicating lactose maldigestion. In children who had ceased breast-feeding, a longer period of lactation was associated with poorer intestinal permeability (P=0·031), and poorer height-for-age (P=0·024), which was an unexpected result. No significant relationships were found between intestinal permeability and growth, or with morbidity and helminth infection, except in children with Giardia lamblia who had worse lactulose:mannitol ratios than those without (0·43 v. 0·25 respectively, P=0·014). It is likely that insults to the gut (e.g. Giardia) and challenges to the immune system (weaning) have a different impact in early and late infancy.

Mice were deprived of food for a period of 72h at varying times relative to the time of infection with Paracoccidioides brasiliensis. Host resistance was diminished profoundly when the period of food deprivation was from 48h before to 24h after infection (group B). When food deprivation was initiated immediately after infection (group C), host resistance was reduced less profoundly. When food deprivation was initiated at 24 and 48h post-infection, reductions in host resistance were only moderate or not observed respectively. These results suggest that the earlier in the course of infection starvation occurs, the more profoundly host resistance is impaired. When food deprivation was initiated 72h before infection, finishing at the time of infection (group A), the reduction in host resistance was considerably less profound compared with group B mice, suggesting that refeeding initiated immediately after infection is responsible for rapid restoration of the antifungal resistance in starved mice. Infection-induced responses of corticosterone and interferon-γ were changed according to the timing of food deprivation. Group A mice, similar to non-fasted controls, showed an infection-induced increase in serum corticosterone concentration, while groups B and C did not. Group C mice showed a substantially greater infection-induced increase in serum interferon-γ compared with the other fasted and non-fasted control groups.

Diets containing soluble NSP (sNSP) and resistant starch (RS) increase hindgut fermentation in pigs, which in turn increases the incidence of swine dysentery (SD) after infection with the intestinal spirochaete Brachyspira hyodysenteriae. In the present study pigs were fed diets based on either wheat or sorghum, fed either raw or treated by extrusion, and/or with the addition of dietary enzymes to reduce RS and/or sNSP content. The aim was to determine the effects of these treatments on pig performance, large intestinal fermentation and expression of SD. Weaned pigs (n 132) were fed experimental diets for 4 weeks, when half the pigs in each treatment group were euthanased and samples collected to assess the influence of the diet on hindgut fermentation. The remaining pigs then were infected with B. hyodysenteriae, and monitored for development of SD. In general, compared with pigs fed raw wheat, fermentation in all parts of the large intestine was reduced either by feeding raw sorghum-based diets, or by feeding diets that were extruded. The addition of enzymes that degrade RS or sNSP reduced fermentation only in the distal parts of the large intestine. The incidence of SD was lower in pigs fed sorghum-based diets, and some of the extruded diets, but none of the dietary treatments offered full protection against SD. Multiple regression analysis of the results from all three experiments showed that colonisation by spirochaetes was highly related to dietary sNSP concentrations, whilst development of SD was similarly influenced by RS content of the diet.

The objective of this investigation was to compare, at several levels of intake, the capacity of diverse cold-pressed plant oils to support development of acquired immune competence assessed in vivo in the weanling mouse. Safflower, maize, soyabean, rapeseed, flaxseed and olive oils were selected to represent widely differing 18: 1n-9, 18: 2n-6 and 18: 3n-3 contents, and each oil was fed at three dietary levels (40, 80 and 160 g/kg) as the exclusive source of fat. C57BL/6J mice, ten males and ten females, had free access to each diet for 28 d beginning at 19 d of age. The primary serum haemagglutinin response to sheep red blood cells and the primary cutaneous delayed hypersensitivity response to dinitrochlorobenzene were used to assess humoral and cell-mediated competence respectively, on day 28. A zero-time control group, assessed immunologically at 19 d of age, was also included (n 32). Independently of dietary oil level, flaxseed, rapeseed, olive and soyabean oils supported development of a more vigorous antibody response than safflower (a useful point of reference, being rich in 18: 2n-6 but low in 18: 1n-9 and 18: 3n-3), whereas only flaxseed oil supported development of cell-mediated responsiveness exceeding that of safflower-fed mice. Independently of oil type, development of both immunological indices correlated negatively with intake of 18: 2n-6, and development of humoral competence varied inversely with dietary oil level. A low content of 18: 2n-6, perhaps less than 20 g/100 g fatty acids, appears important to the capacity of a plant oil to support development of acquired immune competence in the young.

Although protein–energy malnutrition is a common cause of immunodeficiency, the immune function in underweight anorexia nervosa (AN) patients usually seems to be better preserved than would be expected. However, a deranged cytokine production and its consequences are currently being investigated in these patients. This study was aimed at measuring, over time, the capacity of peripheral blood mononuclear cells (PBMC) from AN in-patients to produce several cytokines involved in the regulation of immune responses. The in vitro production of interferon (IFN)-γ, interleukin (IL)-2, tumour necrosis factor (TNF)-α, IL-6 and IL-1β by phytohaemagglutinin-stimulated PBMC were assessed on forty female adolescents with AN. These measures were carried out twice, upon hospital admission and at discharge, which occurred on average after 1 month. Thirty-five control subjects were also studied. Cytokines were measured by ELISA kits. The production of TNF-α and IL-6 was lower and production of IL-1β higher in AN patients than in the control group at both time points of assessment. Refeeding for 1 month was not enough time to reverse these differences and patients still had a low body weight at discharge. IFN-γ production was lower in the patients than in control subjects only at discharge and no differences were found in IL-2 production between both groups. The results suggest that a mechanism involving modifications in the secretion pattern of proinflammatory cytokines could explain some immune function findings in underweight AN patients.

Thirty growing yaks Bos grunniens or Poephagus grunniens, 1·0–3·5 years and 50–230kg, from their native altitudes (3000–4000m), were used to study the basal metabolism in this species and to evaluate the effects of high altitude and season on the energy metabolism. Fasting heat production (FHP) was measured at altitudes of 2260, 3250 and 4270m on the Tibetan plateau in both the summer and the winter, after a 90d adaptation period at each experimental site. Gas exchanges of the whole animals were determined continuously for 3d (4–5 times per d, 10–12 min each time) after a 96 h starvation period, using closed-circuit respiratory masks. Increasing altitude at similar ambient temperature (Ta) did not affect (P>0·10) FHP in the summer, but decreased (P<0·05) it at different Ta in the winter. However, the decrease of FHP in the winter was mainly due to the decrease of Ta instead of the increase of altitude. In the summer, the respiratory rate, heart rate and body temperature were unaffected by altitude, except for a decrease (P<0·05) in body temperature at 4270m; in the winter, they were decreased (P<0·05) by increasing altitude. In both seasons, the RER was decreased (P<0·05) by increasing altitude. At all altitudes for all groups, the daily FHP was higher (P<0·05) in the summer (Ta 6–24°C) than in the winter (Ta 0 to -30°C), and the Ta-corrected FHP averaged on 920 kJ/kg body weight0·52 at Ta 8–14°C and on 704 kJ/kg body weight0·52 at Ta -15°C respectively. We conclude that in the yak high altitude has no effect on the energy metabolism, whereas the cold ambient temperature has a significant depressing effect. The results confirm that the yak has an excellent adaptation to both high altitude and extremely cold environments.

Using controlled in vivo and in vitro pharmacological methods, we evaluated the safety of papaya (Carica papaya) consumption in pregnancy with reference to its common avoidance during pregnancy in some parts of Asia. Ripe papaya (Carica papaya L. (Caricaecae) blend (500 ml/l water) was freely given to four groups of Sprague-Dawley rats at different stages of gestation (days 1–5, 6–11, 12–17 and 1–20). The control group received water. The effect of ripe papaya juice and crude papaya latex on pregnant and non-pregnant rats' uteri was also evaluated using standard isolated-organ-bath methods. The daily volumes (ml) of ripe papaya blend consumed by the treated group were significantly (P<0·05) more than water consumed by the control (control 40·3 (<FONT SIZE="-2">SD</FONT> 11·6) v. treated 64 (SD 19·0)). There was no significant difference in the number of implantation sites and viable fetuses in the rats given ripe papaya relative to the control. No sign of fetal or maternal toxicity was observed in all the groups. In the in vitro study, ripe papaya juice (0·1–0·8 ml) did not show any significant contractile effect on uterine smooth muscles isolated from pregnant and non-pregnant rats; conversely, crude papaya latex (0·1–3·2 mg/ml) induced spasmodic contraction of the uterine muscles similar to oxytocin (1–64 mU/ml) and prostaglandin F2α (0·028–1·81 μM). The response of the isolated rat uterine smooth muscles to 0·2 mg crude papaya latex/ml was comparable to 0·23 μM prostaglandin F2α and 32 mU oxytocin/ml. In the 18–19 d pregnant rat uterus, the contractile effect of crude papaya latex was characterized by tetanic spasms. The results of the present study suggest that normal consumption of ripe papaya during pregnancy may not pose any significant danger. However, the unripe or semi-ripe papaya (which contains high concentration of the latex that produces marked uterine contractions) could be unsafe in pregnancy. Though evaluation of potentially toxic agents often relies on animal experimental results to predict risk in man, further studies will be necessary to ascertain the ultimate risk of unripe papaya–semi-ripe papaya consumption during pregnancy in man.

The Tanita TBF-305 (Tanita Corp., Tokyo, Japan) is a commercially available foot-to-foot bioelectrical impedance analysis (BIA) system. The manufacturer-supplied equations incorporate gender, mass, height, activity category and a measured impedance value to determine % body fat (BF). The purpose of the present study was to determine whether the manufacturer-supplied ‘adult’ and ‘athlete’ equations provided an accurate estimate of % BF for a group of young men with varying activity levels. Fifty-seven men (18–35 years old) were categorized into the following groups: (1) highly active (HA) (≥10·0 h aerobic activity/week); (2) moderately active (MA) (2·5–10·0 h aerobic activity/week); (3) less active (LA) (<2·5 h aerobic activity/week). The % BF was measured using the BIA ‘athlete’ and ‘adult’ modes. After BIA measurements, residual volume was measured and hydrostatic weighing (HW) was performed. The amount of activity performed by each group was significantly different (P<0·001). No significant differences were found between the % BF determined by the ‘athlete’ mode and HW for HA (P=0·309) and MA (P=0·091). However, a significant difference was found for LA (P=0·001). The % BF determined by the ‘adult’ mode and HW was not different for LA (P=0·395), but was significantly different for MA (P<0·001) and HA (P<0·001). The choice of activity mode on the foot-to-foot BIA significantly alters prediction of % BF. With careful selection of activity mode, there was no statistical difference between % BF determined by HW and the BIA, but the range of individual error scores was large.