It has been suggested that energy expenditure is higher in subjects consuming reduced-fat, high-carbohydrate diets than in subjects consuming full-fat, low-carbohydrate diets. In a 6-month randomized, controlled trial, seventeen women and twenty men (age 20–35 years; BMI 22–28 kg/m2)had free access either to a range of about forty-five reduced-fat products or the full-fat equivalents. At the end of the 6 months, energy intake, sleeping metabolic rate (SMR), average daily metabolic rate (ADMR), and physical activity (AO) were measured. The intervention resulted in a mean difference of the change of the fat content of the diet of 6% of energy (P < 0·01) between the two groups. SMR, ADMR and AO were virtually the same in both groups. The results suggest that the change in fat content of the diet has no effect on physical activity and energy expenditure. However, subjects with a higher activity level consumed more carbohydrate (ADMR/SMR: r = 0·49, P < 0·01; AO: r = 0·57,p=0·001)

Nutrients not absorbed in the small bowel will form substrates for microbial growth in the colon which may have implications for the development of colon cancer. The aim of the present study was to investigate whether fibre-rich oat and barley diets increase the excretion of energy-supplying nutrients from the small bowel compared with a low-fibre wheat diet, and whether a possible. increase could be related to the β-glucan content. Nine ileastomy subjects were served four types of bread together with a low-fibre basal diet (12 g dietary fibre/d). The breads were based on either wheat flour (W diet, 7 g dietary fibre/d), oat bran (OB diet, 29 g dietary fibre/d), the same amount of oat bran with addition of β-glucanase (EC 3.2.1.4) (OBE diet, 19 g dietary fibre/d) or a fibre-rich barley fraction (B diet, 35 g dietary fibre/d). An increased ileal excretion of starch was observed with the barley diet but no effect of the oat β-glucan on starch recovery was found. The NSP + Klason lignin in the ileostomy effluents accounted only for 24, 31, 24 and 35% of the gross energy excretion in the W, OB, OBE and B diet periods respectively. A large part of the dry weight and energy (30, 21, 28 and 27%, in the W, OB, OBE and B diets respectively) in the effluents could not be identified as fat, protein, total starch or NSP + Klason lignin. This unidentified part was probably made up of oligosaccbarides, endogenous losses and nutrient complexes. Methods for identifying and analysing these components should be developed and their role as substrates for colonic fermentation and colon cancer development ought to be investigated.

Vitamin A status of 260 groups of twenty-five males or twenty-five females, aged 35–64 years, surveyed in twenty-four provinces of the People's Republic of China, was assessed by measuring plasma retinol, retinol-binding protein and β-carotene concentrations. Direct measurements of food intake over a 3 d period and questionnaire data on the frequency of consumption of vegetables, fruit, animal products and other dietary items were also used. Vitamin A status appeared to be low only in specific counties but in general was satisfactory or only marginally deficient. Plasma harotene levels were strikingly low in comparison with Western levels despite generous vegetable consumption suggwg that intake of vitamin A precursors may have been adequate but not abundant enough to maintain high circulating plasma levels of β-carotene. Plasma β-carotene, for both males and females, was significantly correlated with the frequency of consumption of green vegetables. Plasma retinol, for males, was highly correlated with meat, fish, oil and alcohol consumption expresPed both in quantity or frequency of consumption. Higher levels of plasma retinol, together with lower levels of plasma β-carotene in males compared with females, suggest that men consume more animal products or may have higher retinol requirements and therefore a higher rate of conversion of β-carotene to retinol.

The effect of long-term supplementation with CaCO3 on indices of Fe, Zn and Mg status was investigated in a randomized, double-blind intervention study of sixty lactating Gambian women. The supplement contained 1000 mg Ca and was consumed between meals 5 d/week, for 1 year starting 1.5 weeks postpartum. Compliance was 100%. Plasma ferritin concentration, plasma Zn concentration and urinary Mg output were measured before, during and after supplementation at 1.5, 13, 52 and 78 weeks postpartum. No significant differences in mineral status were observed at any time between women in the supplement and placebo group. Analysis of the longitudinal data series showed that plasma ferritin and Mg excretion were characteristic of the indivdiual (P < 0·001). Within individuals, ferritin concentration was higher at 1.5 weeks postpartum than later in lactation (P = 0.002). Plasma Zn concentration was lower at 1.5 weeks postpartum than at other tima (P < 0·001), an effect which disappeared after albumin correction. Low plasma concentrations of ferritin and Zn indicated that the Gambian women were at high risk of Fe and Zn deficiency. Measurements of α1-antichymotrypsin suggested that the results were not confounded by acute-phase responses. The results of the present study indicate that 1000 mg Ca as CaCO3 given between meals does not deleteriously affect plasma ferritin and Zn concentrations or urinary Mg excretion in women who are at risk of Fe and Zn deficiency

In the present study we have developed the agar-fill method for the measurement of gastrointestinal-tract capacity (GTC) to replace the in vitro water-fill method. This would estimate GTC without using complex equipment and techniques, and can be applied to the measurement of GTC for small laboratory animals. We attempted to confirm the efficiency of the agar-fill method by investigating the relationship between dietary neutral-detergent fibre (NDF) content and GTC. The digestion trials were carried out using the Syrian hamster (Mesocricefus auretus). The trials were conducted using both sexes, two age-groups and three levels of dietary NDF with a cross-classified design. The size of each gastrointestinal organ was determined as tissue weight(TW)and GTC. The DM intake, digestible DM intake, DM digestibility, NDF digestibfity, aciddetergent fibre(ADF) digestibfity and digesta transit time were also measured. GTC increased with increasing NDF content of the diets. TW responded similarly to increasing NDF content, but the response was smaller than that of GTC. DM digestibility decreased with increasing NDF content of the diet. The digestible DM intake did not decrease with increasing NDF because DM intake increased with NDF content. Digesta transit time was not shorter of the high-NDF-diet group but DM intake increased with increasing NDF content. NDF digestibility did not differ significantly between low- and medium-NDF diets. ADF digestibility was low in the low-NDF-diet group.The digestion characteristics were highly correlated with TW and GTC, except for TW of small intestine. These correlations were higher with GTC than with TW. The results of the present study confirm previous findings suggesting that the agar-fill method is a useful means of estimating GTC for small laboratory animals.

Energy intake profoundly influences many endocrine axes which in turn play a central role in development. The specific influence of a short period of mild hypothyroidism, similar to that induced by undernutrition, in regulating muscle development has been assessed in a large mammal during early postnatal life. Hypothyroidism was induced by providing methimazole and iopanoic acid in the feed of piglets between 4 and 14 d of age, and controls were pair-fed to the energy intake of their hypothyroid littermates. Thyroid status was evaluated, and myofibre differentiation and cation pump concentrations were then assessed in the following functionally distinct muscles: longissimus dorsi (l. dorsi), soleus and rhomboideus. Reductions in plasma concentrations of thyroxine (T4; 32%, P < O·Ol), triiodothyronine (T3;48%, P < 0·001), free T3, (58%, P < 0·001)and hepatic 5'-monodeiodinase (EC 1.11.1.8) activity (74%, P < 0·001) occurred with treatment. Small, although significant, increases in the proportion of type I slow-twitch oxidative fibres occurred with mild hypothyroidism, in l. dorsi (2%, P < 0·01) and soleus(7%, P < 0·01). Nuclear T3-receptor concentration in l. dorsi of hypothyroid animals compared with controls increased by 46% (P < 0·001), a response that may represent a homeostatic mechanism making muscle more sensitive to low levels of circulating thyroid hormones. Nevertheless, Na+, K+-ATPase (EC 3.6.1.37) concentration was reduced by 15–16% in all muscles (l.dorsi P< 0·05,soleusP < 0·001, rhomboideusP < 0·05), and Ca2+-ATPase (EC 3.6.1.38) concentration was significantly reduced in the two slow-twitch muscles: by 22% in rhomboideus (P < 0·001) and 23% in soleus (P < 0·05). It is concluded that during early postnatal development of large mammals a period of mild hypothyroidism, comparable with that found during undernutrition, induces changes in myofibre differentiation and a down-regulation of cation pumps in skeletal muscle. Such changes would result in slowness of movement and muscle weakness, and also reduce ATP hydrolysis with a concomitant improvement in energetic efficiency.

The effect of a mixture of organisms (a probiotic mixture) comprising Bacillus, Lactobacillus, Streptococcus, Clostridium, Saccharomyces and Candida(107–8 colony-forming units/g rice bran of each component) on lipid metabolism was compared with that of L. acidophilus and that of S. faecalis. There were four treatment groups: rice bran (control), the mixture of organisms, L. acihphifus or S. faecds (30g/kg) were given to rats in a fat- and cholesterol-enriched diet for 4 weeks. The serum total cholesterol concentration of the group fed on the mixture of organisms was reduced by 15–33% compared with the other groups at the end of the 4week feeding period (P < 0·05). This group also had a lower hepatic cholesterol concentration (36–44%) than the two single-bacteria groups (P < 0·05). 3-Hydmxy-3-methylglutaryl-Co A reductase (NADPH; EC 1.1.1.34) activities of the mixed-organism and L. acidophifus groups were significantly lower (61–63%) than those of the other groups (P < 0·05); the activity of the S. faecalis group was also signikantly lower (42%) than that of the control group (P < 0·05). The faecal cholesterol and bile acid concentrations of the mixed-organism group increased compared with those of the L. acidophilus and S. faecalis groups (P < 0·05). The capacity of the mixed- organism cells to bind bile salt in vitro was significantly higher (approximately 50%) than that of the singlebacteria cells (P < 0·05). On the other hand, cholesterol micelle formation for the mixed-organism cells was significantly (approximately 9%) lower than that of the singlebacteria cells (P < 0·05). These results indicate that the mixture of organisms decreased the synthesis of cholesterol in the liver and increased the loss of steroids from the intestine, in rats. Thus, the mixture of organisms had a hypocholeaterolaemic role

The effects of olive oil and rapeseed oil, two different high-o1eic-acid oils, on plasma LDL and hepatic cholesterol metabolism were compared in guinea-pigs. Animals were fed on semipurified diet containing 150 g fat/kg as either olive oil (OL), rapeseed oil plus 100 g palm oil/kg (C-P) or olive oil plus 350 g safflowerseed oil/kg (OL-S). Olive oil was enriched with safllowerseed oil (OL-S diet) to increase linoleic acid and to decrease palmitic acid concentrations, in order to evaluate whether differences in plasma LDL concentrations were due to intrinsic effects of the specific oil (rapeseed or olive oil) or to differences in the content of specific fatty acids. No differences due to dietary fat source were found in plasma total and HDL-cholesterol levels or in LDL composition. Plasma LDL-cholesterol levels were lower on the C-P diet than the OL diet (P < 0·05) while plasma LDL-cholesterol levels in animals fed on the OL-S diet were not significantly different from either dietary group (P > 0·05). The number of hepatic apo B/E (LDL) receptors was on average 25% higher in animals fed on the C-P diet compared with those fed on diets containing olive oil. Likewise, cardiac muscle lipoprotein lipase (EC 3.1.1.34) activity was significantly higher in the C-P group than in the OL and OL-S dietary groups. Dietary fat source had no effect on hepatic cholesterol levels or 3-hydroxy-3-methylglutaryl (HMG) CoA reductase (EC 1.1.1.34) activity. The results indicate that olive oil and rapeseed oil, both rich sources of monoumaturated fatty acids, differ in their effect on LDL metabolism in the guinea-pig.

Dietary supplementation with oligofructose (OFS; 100 g/kg), a non-digestibleoligomer of β-D-fructose, decreases serum triacylglycerols in serum and VLDL of rats. In order to investigate the role of hepatic metabolism in the hypolipidaemic effect of OFS, male Wistar rats were fed on a standard diet with or without 1OOg Raftilose® P95/kg as OFS source for 30 d. OFS feeding (1) significantly decreased triacylglycerol and phospholipid concentrations in both blood and liver, (2) increased the glycerol-3-phosphate liver content but decreased the hepatic activity of glycerol-3-phosphate acyltransferase (EC 2.3.1.15), suggesting a decrease in acylglycerol synthesis, (3) did not affect the blood non-caterified fatty acid concentrations, but (4) reduced by 54% the capacity of isolated hepatocytesto synthesize and secrete triacylglycerols from labelled acetate; the activity of fatty acid synthase, a key lipogenic enzyme was also significantly decreased. These findings suggest that OFS decreases serum triacylglycerols by reducing de nova fatty acid synthesis in the liver; the lower insulin level in the serum of OFS-fed rats could explain, at least partly, the metabolic effect induced by such nondigestible carbohydrates.

Retinol-binding protein (RBP) and transthyretin (TTR) in the plasma, liver and kidney, retinol in plasma, and total vitamin A in the liver were measured in rats 6 weeks after diabetes mellitus had been induced by streptozotocin (STZ). The diabetic rats gained 83% less weight despite consuming 45% more feed than the non-diabetic controls. Plasma and kidney concentrations of RBP and TTR were significantly lower in diabetic than in the non-diabetic control rats. Unlike the retinol carrier proteins, plasma albumin concentrations remained unaffected. Plasma concentrations of retino1 were decreased while its hepatic levels increased in the diabeticanimals. The depressed circulatory levels of retinol may reflect an altered metabolism of its transport proteins

The present study examined the effects of Se, vitamin E and combined Se and vitamin E deficiencies in rats on plasma lipid, Lipoprotein and apolipoprotein (apo) concentrations. Deficiencies were induced by feeding rats the respective diets for 6 weeks. The study shows that Se deficiency results in increased concentrations of plasma cholesterol and apo E. Both could be explained by an increase in the HDL1 fraction. Vitamin E deficiency alone had no significant effect on plasma lipid, lipoprotein and apo concentrations. Se deficiency in combination with vitamin E deficiency leads to an increase in plasma LDL and apo B concentrations. These results point to the need for further investigations on the mechanism by which Se deficiency affects lipoprotein metabolism.

The mechanism underlying the reduced Cu status in rats fed on a high-sulphide diet was investigated. Male rats aged 6 weeks were fed ad libitum on purified diets containing either 0 or 500 mg S2-/kg and demineralized water for a period of 2 weeks. The high-sulphide diet had no effect on feed intake, body-weight gain or weight of liver and kidney bat significantly reduced Cu concentrations in plasma and kidney. Biliary Cu excretion was decreased significantly in rats fed on the high-sulphide diet. Apparent Cu absorption (Cu intake -faecal Cu) and true Cu absorption (Cu intake - (faecal Cu - biliary Cu)) were significantly lowered after sulphide feeding for 2 weeks. Rats fed on the high-sulphide diet excreted less Cu in urine than did the controls. We conclude that high sulphide intake reduces Cu status in rats through inhibition of Cu absorption which is reflected by a decrease in biliary Cu excretion as a secondary feature