The present paper reviews the literature on breakfast to consider reported associations between breakfast and nutritional, physiological and biochemical variables. The contribution of breakfast to achieving nutrition targets for fat, carbohydrate and dietary fibre intakes is also examined as are the potential effects of fortified breakfast cereals on intakes of micronutrients and nutritional status. Breakfast consumption, particularly if the meal includes a breakfast cereal, is associated with lower intakes of fat and higher intakes of carbohydrate, dietary fibre and certain micronutrients. These findings may be relevant to population groups which could be at risk from low intakes of certain micronutrients, but further clarification of benefit is needed from studies of nutritional status. Associations between breakfast consumption and lower cholesterol levels have been reported, while lower body weights have been seen amongst breakfast eaters. It is concluded that breakfast consumption is a marker for an appropriate dietary pattern in terms of both macro- and micronutrients, particularly if breakfast cereals are included in the meal.

The effect of a daily intake of 14g inulin added to a low-fat spread on fasting blood lipids and gastrointestinal symptoms was investigated in sixty-four young healthy women in a randomized double-blind crossover study involving two periods of 4 weeks. The test spread with and without inulin replaced habitual spread during the test periods. No significant differences between the test periods in plasma total cholesterol, HDL-cholesterol, LDL-cholesterol and triacylglycerol concentrations were observed. Gastrointestinal symptoms assessed with questionnaires showed that in the inulin period there was a significantly (P<0·05) higher degree of discomfort from flatulence and other gastrointestinal symptoms than in the control period. In general, there was no indication of intestinal adaptation to this level of intake of inulin.

The objectives of the present study were to determine the feasibility of using manufactured foods, enriched with eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA) as a means of increasing the intake of these n−3 polyunsaturated fatty acids (PUFA), and to determine the effect of the consumption of these foods on postprandial lipaemia and other metabolic responses to a high-fat mixed test meal. Nine healthy, normotriacylglycerolaemic, free-living male volunteers (aged 35–60 years) completed the randomized, controlled, single-blind, crossover study. The study consisted of two periods (each of 22d) of dietary intervention, separated by a 5-month washout period. During these two periods the subjects were provided with the manufactured foods enriched with EPA and DHA (n−3 enriched) or identical but unenriched foods (control). A mixed test meal containing 82g fat was given to the fasted subjects on day 22 of each dietary intervention period. Two fasting, and thereafter hourly, blood samples were collected from the subjects for an 8h period postprandially. Plasma triacylglycerol, total and HDL-cholesterol, non-esterified fatty acids (NEFA), glucose and immunoreactive insulin levels, post-heparin lipoprotein lipase (EC 3.1.1.34) activity and the plasma free fatty acid and phospholipid fatty acid compositions were measured. A mean daily intake of 1·4 g EPA + DHA (0·9 g EPA, 0·5 g DHA) was ingested during the n−3-enriched dietary period, which was significantly higher than the intake during the habitual and control periods (P <0·001) assessed by a 3 dweighed food intake. A significantly higher level of EPA + DHA enrichment of the plasma fatty acids and phospholipids (P < 0·001) after the n−3-enriched compared withthe control intervention periods was also found. The energy intake on both of the dietary intervention periods was found to be significantly higher than on the habitual diet (P <0·001), with an increase in body weight of the subjects, which reachedsignificance during the n−3 PUFA-enriched dietary intervention period (P < 0·04). The palatability of the enriched foods was not significantly different from that of the control foods. Significantly higher fasting plasma HDL-cholesterol and glucose concentrations were found after the n-3 PUFA-enriched compared with the control intervention period (P < 0·02 and P < 0·05 respectively). No significant differences were found for the postprandial lipid and hormone measurements, except for significantly lower levels of NEFA at 60min after the n−3-enriched intervention period (P< 0·04). Enriched manufactured foods were a feasible vehicle for increasing n−3 PUFA intake. However the nature of the foods provided as the n−3 vehicle may have contributed to the increased body weight and higher energy intakes which were adverse consequences of the intervention. These factors, together with the short duration of the study may have been reponsible for the failure to observe significant plasma triacylglycerol reductions in response to daily intakes of 1·4g EPA+DHA.

Samples and extracts of foliage from African multipurpose trees were screened for their effects on rumen protozoa and bacteria with a view to predicting their safety as feed supplements and for identifying species with potential antiprotozoal activity. The species tested were Acacia aneura, Charnaecytisus palmensis, Brachychiton populneum, Flindersia maculosa, Sesbania sesban, Leucaena leucocephala and Vernonia amyedalina. Antimicrobial effects were mild except for S. sesban, which was highly toxic to rumen protozoa in vitro, and A. aneura, which was toxic to rumen bacteria. The antiprotozoal factor in S. sesban was apparently associated with the fraction of the plant containing saponins. When S. sesban was fed to sheep, protozoal numbers fell by 60 % after 4 d, but the population recovered after a further 10 d. In vitro experiments demonstrated that washed protozoa from later times were no more resistant to S. sesban than on initial exposure, suggesting that other micro-organisms, probably the bacteria, adapted to detoxify the antiprotozoal agent. Thus S. sesban may be useful in suppressing protozoa and thereby improving protein flow from the rumen, but only if the bacterial metabolism of the antiprotozoal factor can be avoided.

The nutritional regulation of glucose transporter GLUT4 was studied in eight muscles and four adipose tissues from two groups of preruminant (PR) or ruminant (R) calves of similar age (170d), empty body weight (194kg) at slaughter, and level of net energy intake from birth onwards. Isocitrate dehydrogenase (EC 1.1.1.41) activity in muscles was not different between PR and R except in masseter muscle from the cheek (+71 % in R; P<0·003), which becomes almost constantly active at weaning for food chewing. Basal and maximally-insulin-stimulated glucose transport rate (GTR) per g tissue wet weight in rectus abdominis muscle were significantly higher in R calves (+31 and 41 % respectively; P<0·05). GLUT4 protein contents did not differ in muscles from PR and R except in masseter (+74 % in R; P<0·05) indicating that the increased GTR in rectus ubdominis cannot be accounted for by an enhanced GLUT4 expression. GLUT4 mRNAlevels did not differ between the two groups of animals in all muscles suggesting a regulation of GLUT4 at the protein level in masseter. GLUT4 number expressed on a per cell basis was lower in adipose tissue from R calves (-39 % P<0·05) and higher in internal than in peripheral adipose tissues. In summary, the regulation of GLUT4 in calves at weaning differs markedly from that previously described in rodents (for review, see Girard et al. 1992). Furthermore, significant inter-individual variations were shown for metabolic activities in muscle and for biochemical variables in adipose tissue.

The effect of body fat content on the protein metabolism of energy-restricted sheep has been studied in two experiments. In the first experiment, six Suffolk-cross wether sheep, three weighing about 39 kg and three of about 61 kg, were given progressively increasing amounts of casein-N from 0 to 3000 mg N/kg metabolic body weight (W0·75) daily with constant energy, 91 kJ/kg W0·75 daily, from a high-propionic acid mixture of volatile fatty acids (VFA). In the second experiment, two lean and two fat sheep of similar body weights were given progressively increasing amounts of casein with the same VFA mixture. All the animals attained a positive N balance when they were in negative energy balance. N balance was not affected by body fatness of the magnitude studied, although lean animals utilized increasing levels of standard VFA (acetate-propionate-butyrate 65:25:10, molar proportions) infusion for N accretion more efficiently than fat animals. Endogenous energy was utilized for protein accretion with an efficiency of 0·56. Supply of glucogenic VFA equivalent to 28 mmol glucose/kg W0·75 reduced fasting N excretion by 39%. Fasting heat production decreased from 335 to 300 kJ/kg W0·75 with the infusion of casein and glucogenic VFA. It is argued that fasting induces additional heat losses due to raised protein metabolism and is unsuited as a baseline for dietary assessment.

One-day-old broiler chickens were fed on a control diet based on maize and maize starch or diets containing 30g/kg of 89 % deacetylated chitin (chitosan) or low-methoxyl (34 % degree of esterification) pectin. Feeding of the chitosan diet to chickens significantly reduced body weights and feed intakes compared with animals fed on control or pectin diets on days 5 and 11 of the experiment. On day 12, significant reductions in total plasma cholesterol and HDL-cholesterol concentrations were observed among birds fed on the chitosan but not the pectin diet in relation to control-fed animals. A concomitant increase in the plasma HDL-cholesterol:total cholesterol ratio was observed among chitosan-fed chickens. The generally reduced concentrations of primary and total bile acids in the duodenum of birds fed on the fibre-containing diets on day 13 may have been an indication of a delay in the production and/or secretion of bile. Viscosity of the three broiler-chicken diets was measured after suspension in water, acidification and finally neutralization of the suspensions, in an attempt to simulate the effect of changes in pH and dilution of diets occurring in the gizzard and small intestine of chickens. Viscosity of the chitosan diet was significantly elevated after acidification and significantly reduced at neutralization in comparison with the control and pectin-containingdiets suggesting that the hypolipidaemic influence of chitosan observed in the present study may be due to interruption of enterohepatic bile acid circulation rather than increased viscosity in the small intestine of chickens. The low viscosity of the pectin diet in vitro together with the absence of a hypocholesterolaemic effect of this diet when fed in vivo precludes any conclusion regarding the hypocholesterolaemic mechanism of pectin observed in earlier studies.

The present study reports data on absorption of orally administered glutathione (GSH) in rat jejunum and in other organs, and the possible role of specific transport systems of GSH and γ-glutamyltranspeptidase (EC 2.3.2.1; γ-GT) activity. GSH levels were measured simultaneously in various organs after oral GSH administration to untreated rats and rats treated with L-buthionine sulfoximine (BSO) or acivicin (AT125). BSO selectively inhibits GSH intracellular synthesis and AT125 is a specific inhibitor of γ-GT activity. GSH levels were also measured after oral administration of an equivalent amount of the constituent amino acids of GSH to untreated and BSO-treated rats. Significant increases in GSH levels were found in jejunum, lung, heart, liver and brain after oral GSH administration to untreated rats. GSH increases were also obtained in all organs, except liver, when GSH was administered to rats previously GHS-depleted by treatment with BSO. The analysis of all results allowed us to distinguish between the increase in GSH intracellular levels due to intact GSH uptake by specific transporters, and that due to GSH degradation by γ-GT activity and subsequent absorption of degradation products with intracellular resynthesis of GSH; both these mechanisms seemed to be involved in increasing GSH content in heart after oral GSH administration. Jejunum, lung and brain took up GSH mostly intact, by specific transport systems, while in liver GSH uptake occurred only by its breakdown by γ-GT activity followed by intracellular resynthesis.

The aim of the present study was to evaluate the links between chronic fat-cholesterol intake, postprandial lipaemia and atherogenesis in New Zealand White rabbits. Adult rabbits were fed on either a low-fat control diet (LF) or a high-fat, high-cholesterol diet (HF). Rabbits received a test meal containing [3H]cholesterol and [14C]triolein on days 0 and 63 for the LF group and days 14,28, 42,63 and 84 for the HF group. Blood was collected 24h post-absorptively and 10,24,34 and 48h after test-meal intake. Post-absorptive as well as postprandial lipoproteins and lipaemia were not modified in the LF rabbits, who did not show any atheroma deposition on day 119. In HF rabbits, postprandial plasma triacylglycerols peaked 24–34h after meal intake. The 0-48 h areas under the curves of triacylglycerol andtriacylglycerol-rich lipoproteins (TRL) steadily increased with time of chronic lipid feeding with values significantly higher than those in the LF rabbits. The postprandial plasma and TRL concentrations of dietary radiolabelled lipids were significantly higher in HF than LF rabbits. Post-heparin lipoprotein lipase (EC 3.1.1.34) and hepatic lipase (EC 3.1.1.3) activities were twofold higher in HF rabbits than in LF rabbits at day 105. In HF rabbits, a marked atheroma plaque deposition in the aorta was observed (30·9 (SE 3·9) % of total surface). The extent of atheroma deposition was positively correlated to the postprandial responses of plasma total triacylglycerols and dietary-derived lipids as well as total cholesterol and dietary-derived cholesterolin HF rabbits. In conclusion, chronic ingestion of a HF diet led to marked increases in postprandial lipaemia and TRL particles, and atheroma deposition.

Using germ-free rats inoculated with a human faecal flora (gnotobiotic rats), the effects of three oligosaccharides (β-fructo-oligosaccharides (FOS), β-galacto-oligosaccharides (TOS) and α-gluco-oligosaccharides (GOS)) on intestinal bacterial metabolism were compared. The animals were fed on either a control diet or diets containing 4Og/kg of GOS, FOS or TOS. FOS and TOS were the preferred growth substrates for Bifidobacteria which increased in number by 2 log values in faeces of rats when compared with rats fed on GOS or control diets. Ingestion of TOS specifically induced hydrolysis of the substrate, and did not modify the activity of any other enzymes measured in the caecum. GOS led to a non-specific enzymic induction of β-galactosidase (EC 3.2.1.23), β-glucosidase (EC 3.2.1.21) and α-glucosidase (EC 3.2.1.20) activities whereas β-glucuronidase (EC 3.2.1.31) was lowered. Compared with the control group, FOS and TOS diets led to a significant increase in H2 and CH4 excretion; the GOS diet increased only CH4. Analysis of caecal contents revealed a decrease in pH for all diets compared with controls. Total short-chain fatty acid (SCFA) concentration increased significantly in all groups, but the SCFA profile differed between treatment groups. It was concluded that the three oligosaccharides studied had different effects which may be linked to their chemical structure. Some of these effects may be beneficial to human health

Medicago sativa (lucerne) is used as a traditional plant treatment of diabetes. In the present study, administration of lucerne in the diet (62·5 g/kg) and drinking water (2·5 g/l) reduced the hyperglycaemia of streptozotocin-diabetic mice. An aqueous extract of lucerne (1 mg/ml) stimulated 2-deoxy-glucose transport (1·8-fold), glucose oxidation (1·7-fold) and incorporation of glucose into glycogen (l·6-fold) in mouse abdominal muscle. In acute 20 min tests, 0·25–1 mg/ml aqueous extract of lucerne evoked a stepwise 2·5–6·3-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0·5 mM-diazoxide, and prior exposure to extract did not affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby negating a detrimental effect on cell viability. The effect of extract was potentiated by 16·7 mM-glucose and by 1 mM-3-isobutyl-1-methylxanthine. L-Alanine (10 mM) and a depolarizing concentration of KCI (25 mM) did not augment the insulin-releasing activity of lucerne. Activity of the extract was found to be heat stable and largely acetone insoluble, and was enhanced by exposure to acid and alkali (0·1 M-HCI and NaOH) but decreased 25% with dialysis to remove components with molecular mass <2000 Da. Sequential extraction with solvents revealed insulin-releasing activity in both methanol and water fractions indicating a cumulative effect of more than one extract constituent. The results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in the traditional antidiabetic plant, Medicago sativu.

An experiment was conducted to study the efficacy of two tomato pastes and aronia nectar (fruit juice + pulp from the black chokeberry, Aronia melanocarpa Elliot) as inhibitors of nitrosamine production in cancer prophylaxis programmes. White male rats of the Wistar strain were employed in an acute trial. Aminopyrin + sodium nitrite (APSN) were used as precursors for generation of endogenous nitrosamine. The animals were allocated to different dietary groups and fed by intubation with APSN or APSN + food products. Introduction of tomato paste (TP), high-β-carotene tomato paste (HCTP) and aronia nectar (AN) as inhibitors of n−nitrosamine formation exerted a positive effect on blood and liver variables which was demonstrated by decreased concentrations of glutamic-oxaloacetic transaminase (EC 2.6.1.1), glutamic-pyruvic transaminase (EC 2.6.1.2) and uric acid in serum and lipid content in hepatocytes. Animals treated with APSN developed dystrophic changes in liver such as centrolobular necrosis, intense exangia, and enlarged cells with two, often large, pyknotic nuclei, while the structure of livers of rats fed with TP, HCTP or AN was well protected and almost normal. TP had a particularly beneficial effect on serum total protein and albumin concentrations as had AN on the urea value. The inhibitory effect of th food products used is explained by their chemical nature including pH, ascorbic index (ascorbate:nitrate), lycopene and β-carotene contents.