Paracellular 45Ca absorption and temporal systolic blood pressure (SBP) measurements were recorded in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) ratsfed on casein (C) and soya-bean-protein isolate (S) diets, containing 20 (H), 5 (M) and 0.5(L)g Ca/kg. Similar measurements were also taken in SHR rats only fed on C-M and S-M dietssupplemented with 30 g caseinophosphopeptides (CPP)/kg. Absorption of 45Ca fromthe ileal loop was equivalent in both SHR and WKY animals and largely affected by the level ofdietary Ca. In addition, animals fed on C diets exhibited significantly (P < 0.05) greater ileal absorption of 45Ca compared with S-fed animals. This result was attributed to the presence of CPP and a greater (P < 0.05) proportion of soluble 45Ca inthe contents of the ileum. Animals fed on S diets supplemented with CPP confirmed this finding.The SBP of SHR rats was higher (P < 0.01) than WKY controls after 9–10 weeks of age. The temporal pattern of observed hypertension was independent of dietary influence in the SHR. The severity of hypertension in SHR rats was affected only by dietary Ca deficiency, and not byCa supplementation or CPP enhancement of Ca bioavailability. These findings suggest that trypticdigestion products of casein in milk can enhance Ca bioavailability by increasing Ca solubility; however, this action had no effect in reducing hypertension in SHR.

Administration of large oral doses of retinyl palmitate has become the most widely practised vitamin A deficiency prevention strategy in developing countries. We conducted a follow-up study among 220 Senegalese children aged 2–7 years suffering from moderate undernutrition to determine the efficacy of vitamin A treatment on their vitamin A status assessed by biochemical and cytological (impression cytology with transfer) methods. The first examination (T = 0 m[onth]) was carried out during April 1989, before the mango (Mangifera indica L,) harvest. The second examination (T = 2 m) was carried out 2 months after vitamin A treatment during June 1989 when ripe mangoes become widely available. Conjunctival cells of the eyes of the children with or without ocular inflammation were responsive to vitamin A administration (P < 0.01). There was a significant increase (P < 0.001) in mean serum retinol and β-carotene levels between T = 0 m and T = 2 m. Mean serum retinol-binding protein (RBP) and transthyretin (TTR) levels did not differ significantly (P > 0.05) at T = 0 m and T = 2 m. Despite the intake of vitamin A, 54% of the children who had abnormal cytology at T = 0 m remained abnormal at T = 2 m. This was due to inadequate levels of TTR and RBP, presumably due to the cereal diet eaten by the Senegalese population. Children with abnormal eye cytology had lower serum retinol levels than those with normal eyes at T = 0 m, and β-carotene values did not correlate with eye cytological abnormalities at T = 0 m. Children with normal cytology had higher serum retinol and also β-carotene levels than those with abnormal cytology after massive oral doses of vitamin A and consumption of mangoes at T = 2 m. Retinyl palmitate may, therefore, only lead to partial cytological improvement due to a lack of retinol-carrier proteins but dietary β-carotene may also be involved

Male adult rats were fed on diets containing 80 g/kg galactomannans with different galactose (G): mannose (M) ratios/kg. The galactomannans were compared with purified cellulose (Solkaflok) and the animals were also fed on a basal diet free from fibre. All diets contained cholesterol (10 g/kg) and sodium cholate (2 g/kg). The three galactomannans were fenugreek gum (1G:1M), guar gum (1G:2M) and locust-bean gum (1G:4M). In comparison with the fibre-free and Solkaflok diets, all three galactomannans lowered the concentrations of cholesterol in both liver and blood plasma. The galactomannans also decreased the rate of hepatic synthesis of cholesterol. Dietary galactomannans increased caecal volatile fatty acids, particularly propionic, increased the weight of the caecum and its contents and increased the amount of water in the faeces. The increase in propionic acid production was significantly related to a decrease in caecal pH, but not to changes in plasma cholesterol or hepatic cholesterol synthesis. These effects were significantly influenced by chemical composition and structure of the galactomannan; they were most evident when the proportion of galactose in the galactomannan was highest (i.e. fenugreek gum). The three galactomannans also differed markedly in their effects on the viscosity of the digesta, but the galactomannan which gave the highest viscosity was least effective in lowering plasma cholesterol. A separate experiment with perfused loops of small intestine in vivo showed that the most effective galactomannan, fenugreek gum, had no direct effect on cholesterol absorption.

The effect of feeding rats purified cowpea (Vigna unguiculata Walp.) trypsin (EC 3.4.21.4) inhibitor in a semi-synthetic high-quality diet based on lactalbumin (10 g inhibitor/kg) for 10 d was a moderate reduction in the weight gain of rats in comparison with controls, despite an identical food intake in the two groups. The reduction in the growth rate was about 20% on a live weight basis. However, the corresponding value calculated from the weight of dry carcasses was less, only about 7%, probably because the water content of the body of the two groups of rats was different. Although most of the cowpea trypsin inhibitor (CpTI) was rapidly broken down in the digestive tract, its inclusion in the diet led to a slight, though significant, increase in the nitrogen content of faeces but not of urine. Accordingly, the net protein utilization of rats fed on inhibitor-containing diets was also slightly depressed while their energy expenditure was elevated. In agreement with results obtained for the protease inhibitors of soya bean, the slight anti-nutritional effects of CpTI were probably due mainly to the stimulation of the growth and metabolism of the pancreas. Thus, the nutritional penalty for increased insect-resistance after the transfer of the cowpea trypsin inhibitor gene into food plants is slight in the short-term.

The pulp of banana fruit (Musa sapientum L. var. Cavendishii) was examined for its cholesterol-lowering effect with male rats fed on a diet containing lard (50 g/kg) and cholesterol (5 g/kg). Freeze-dried banana pulp showed a marked cholesterol-lowering effect when incorporated into a diet at the level of 300 or 500 g/kg, while the banana pulp dried in a hot-air current (65°) did not. Starch and tannin prepared from banana pulp were not responsible for the cholesterol-lowering effect. The results also suggest that banana lipids did not affect the concentration of serum cholesterol. Feeding of dopamine, n-epinephrine and serotonin tended to raise the concentration of serum cholesterol. Thus, all the substances tested which were thought to be susceptible to influence by hot-air drying were unlikely to be responsible for the hypocholesterolaemic effect. However, both soluble and insoluble fibres fractionated from banana pulp had a cholesterol-lowering effect, with the exception of cellulose. It was assumed that a browning reaction undergone during hot-air drying might be related to the disappearance of the hypocholesterolaemic effect of banana pulp dried in a hot-air current. The results obtained support the conclusion that soluble and insoluble components of dietary fibre participate in the hypocholesterolaemic effect of banana pulp.

A double-blind clinical trial was conducted among 9- to 11-year-old children in sixteen schools in the Chon Buri province of Thailand to assess the effects of an iron supplement combined with an anthelminthic agent (i.e. albendazole). In addition to the albendazole, Fe or placebo tablets were distributed to 2268 children enrolled in grades three to five without knowledge of the Fe status of the children. Criteria for case inclusion were: (a) absence of A E Bart's or haemoglobin (Hb) H disease, (b) absence of abnormal Hb EE, and (c) age, 108–144 months. The results showed a significant improvement in the Fe status of the children after 16 weeks of treatment. The increments were: Hb from 124 to 128 g/l, serum ferritin from 34.54 to 104.72 μg/l, transferrin saturation from 24.09 to 35.05%; free erythrocyte protoporphyrin decreased from 444.7 to 281.4 μg/l erythrocytes. These changes were significantly greater than in the control group that received only the anthelminthic agent. However, the administration of albendazole only also resulted in significant changes in the same Fe indicators.

Seed samples from two near-isogenic faba bean (Vicia faba L.) lines were examined for the levels of so-called anti-nutritional factors (ANF). From the ANF known to be present in faba beans, trypsin inhibitor activity, functional lectins, condensed tannins and pyrimidine glycosides were analysed. It was concluded that the lines differed only in the content of condensed tannins being < 0.5 g/kg and 5.2 (sd 0.2) g/kg for the low (LT)- and high (HT)-tannin lines respectively. In addition, the level of pyrimidine glycosides in the LT line was slightly higher than that in the HT line. The LT line showed a reduced proportion of the seed coat (105 v. 119 g/kg) and a lower seed weight (0.85 v. 1.01 g). The apparent ileal and faecal digestibility values of dry matter and nitrogen from the HT and LT line were determined for piglets which were fed on diets containing chromium oxide as a marker. The mean apparent ileal and faecal digestibility values for dry matter for the LT line were 0.694 and 0.889 and for N 0.828 and 0.879 respectively. For the HT line, these values were approximately 0.05 and 0.10 lower (P > 0.05). A multi-enzyme technique was used to predict the in vitro protein digestibility (IVPD) of the two lines. The IVPD of the LT line was 0.965 and about 0.05 higher than the HT line, confirming the difference in digestibility as measured in vivo. The present study shows the positive effects on digestibility of removal of condensed tannins in faba beans which was achieved by plant breeding.

In order to determine whether dietary inadequacies can explain the sub-optimal iron status widely documented in endurance-trained athletes, the food intake records of Fe-deficient and Fe-replete distance runners and non-exercising controls of both sexes were analysed. In all the male study groups the mean dietary Fe intake met the recommended dietary allowances (RDA; > 10 mg/d (US) Food and Nutrition Board, 1989). However, both female athletes and controls failed to meet the RDA with regard to Fe (< 15 mg/d) and folate (< 200 μg/d). There was no difference in the total Fe intakes of Fe-deficient and Fe-replete athletes and the controls of each sex. However, Fe-deficient male runners, but not female runners, consumed significantly less haem-Fe (P = 0.048) than their comparative groups. This suggests that the habitual consumption of Fe-poor diets is a factor in the aetiology of athletes' Fe deficiency.

The selenium content of the 1989 harvest of wheat used for bread making in Scotland ranged from 0.028 μg/g dry weight for home-grown wheat to 0.518 μg/g for Canadian wheat. The tonnage values indicate that 13.8% of the wheat used in bread making came from Canada. This reflects in a calculated dietary intake of 31 μg/d which is well below the recommended levels of 70 and 55 μg for adult males and females respectively (National Research Council, 1989). The average glutathione peroxidase (EC 1.11.1.9) level in 478 samples of human whole blood was 6.08 (se 0.065) units/ml. This increased to 6.65 (se 0.321) in sixty-two subjects consuming brown or wholemeal bread but was unaffected by oily fish consumption. Analysis of a small number of samples of whole milk, eggs and meat indicated slightly higher concentrations than previously published values but this trend was insufficient to compensate for the lower cereal provision of Se.

The milk components lactose and casein enhance the apparent absorption of magnesium and possibly also of calcium, whereas phytate, which occurs in soya-bean products, has an inhibitory effect. This implies that soya-bean beverage v. cow's milk could lower bioavailability of Mg and Ca. This hypothesis was tested in two experiments with growing rats. Feeding soya-bean beverage v. cow's milk consistently lowered body-weight gain, enhanced bone turnover, as measured by increased plasma alkaline phosphatase (EC 3.1.3.1) activity and increased urinary hydroxyproline excretion, and decreased Mg and Ca concentrations in the femur. Because the mineral compositions of the soya-bean beverage and the cow's milk were different, the intake of Mg was higher in rats fed on soya-bean beverage, whereas that of Ca was higher in rats fed on cow's milk. Supplementation of the soya-bean beverage either with phosphorus and Ca or with P, Ca and methionine, to concentrations identical to those in milk, restored growth and bone mineralization. When using diets carefully balanced for Mg, Ca, P, sodium, potassium and methionine, soya-bean beverage v. cow's milk in the diets decreased apparent absorption and urinary excretion of Mg and Ca. Hydrolysis of lactose in milk decreased absorption and urinary excretion of Mg; it did not significantly affect Ca absorption but lowered urinary Ca excretion. The present study shows that soya-bean beverage v. milk depresses Mg and Ca bioavailability, as would be predicted on the basis of reported effects of their purified components.

Marginally vitamin A-deficient 1-d-old chickens capable of remaining healthy for at least 6 weeks were produced using a two-generation model. In this model, hens fed on diets with a limited vitamin A content were used to obtain 1-d-old chickens which were marginally deficient in vitamin A. Only hens with a narrow range of plasma retinol values (0.60–0.85 μmol/l) were satisfactory for this purpose. Above this range the 1-d-old chickens were not marginally vitamin A deficient. Below this range egg production and hatchability were affected to some extent depending on the degree of vitamin A deficiency. Even when egg production and hatchability remained at a high level in such birds, the 1-d-old chickens produced were not sufficiently strong to survive the first weeks of life. The advantages of the two-generation model for producing marginally vitamin A-deficient chickens are the increased uniformity and predictability of the chickens with respect to body-weight, general health and vitamin A status. However, it does take about 3 months to produce such chickens.

The effects of post-valve T-caecum (PVTC) cannulation and end-to-side ileo-rectal anastomosis (IRA) on growth performance, nitrogen retention and intestinal fermentation were measured in growing pigs by comparison with a control group of intact animals. There were no differences between PVTC-pigs and intact pigs in growth performance and N balance. In IRA-animals reduced growth (P < 0.01), less efficient feed conversion (P < 0.01) and decreased N retention (P < 0.001) were found. Indices of fermentation measured in deal digesta of PVTC- and IRA-pigs were considerably different. In IRA-animals the concentration of volatile fatty acids (VFA) was about 112–162 mmol/l, higher (P < 0.001) than in digesta of PVTC-pigs (20–31 mmol/l). The molar proportions of acetate and propionate depended (P < 0.01 and P < 0.001 respectively) on the digesta-collection technique. Concentrations and ratios of VFA measured in PVTC-pigs were similar to reported values. Diaminopimelic acid (DAPA) concentration and N:DAPA ratios measured in digesta were significantly (P < 0.05 and P < 0.001 respectively) different between treatments. All digesta variables measured showed increased microbial activity in digesta of IRA-pigs; thus, an influence on digestibility measurement can be assumed.

In a long-term study nine ileo-rectally anastomosed (IRA) and seven post-valve T-caecum (PVTC)-cannulated pigs were compared with six intact pigs with regard to different blood variables, sodium and potassium retention and weights of selected organs. After surgery, apart from urea and K measured 13 weeks post-surgery, there were no differences in the blood variables between the PVTC-pigs and intact pigs. In IRA-pigs concentrations of creatinine (P < 0.01), Na (P < 0.001), base excess (P < 0.001), pH (P < 0.01) and bicarbonate (P < 0.001) in blood were lower than those in intact pigs. At 13 weeks after surgery the blood K concentration in IRA-pigs was higher (P < 0.001) than that in PVTC-pigs or intact pigs. At 6 weeks after surgery the blood urea concentration in IRA-pigs was higher (P < 0.001) than that in intact and PVTC-pigs. At 13 weeks after surgery the urea concentration in PVTC-pigs was higher (P < 0.001) than those in IRA-pigs or intact pigs. The Na (P < 0.01 11 weeks after surgery) and (P < 0.05 and P < 0.01 5 and 11 weeks after surgery respectively) balances in IRA-pigs were lower than those in intact animals. Na retention was negative for IRA-animals 11 weeks after surgery. Na and K retentions were similar in PVTC-pigs and in intact pigs. The urinary: faecal excretion of Na differed slightly between PVTC-animals and intact animals. At 13 weeks after surgery there were no differences in organ weights between the PVTC-pigs and intact animals. In the IRA-pigs the weights of the liver (P > 0.05), the kidneys (P > 0.05) and the adrenal glands were higher (P < 0.001) than those in the intact animals.