Increased concentrations of n-3 polyunsaturated fatty acids (PUFA), namely eicosapentaenoic acid (20 : 5; EPA) and docosahexaenoic acid (22 : 6; DHA), have been shown to be beneficial in coronary artery disease (CAD). In the present study, the relationships between fish intake and concentrations of serum EPA and DHA and the effects of these fatty acids on serum lipids and lipoproteins were investigated. Two groups of men, one living in a fishing village and the other in a farming village, participated in this study. The daily fish consumption was ten times greater in the fishing village group than in the rural village group and the mortality from IHD in the rural village was four times higher. Serum concentrations of EPA and DHA were significantly higher in the fishing village group (P < 0·001). In this group, the serum concentration of arachidonic acid (20 : 4; AA), was significantly lower (P < 0·001), and the ratio EPA : AA was twice that of the rural village (P < 0·001). Moreover, in the fishing village group, the serum triacylglycerol and total cholesterol levels were significantly lower than those observed in the rural village (P < 0·01 and P < 0·05 respectively). In the fishing village group the serum LDL-cholesterol concentration was also lower, although the difference was not significant. Our results reinforce the hypothesis that a high intake of n-3 PUFA provides protection against CAD.

This present case report describes two siblings with severe type V hyperlipoproteinaemia, diagnosed very early in life and due to the combination of the common apolipoprotein (Apo) E2 allele and a rare mutant variant of ApoE, ApoE3 (Arg 136 → Ser). Phenotyping of ApoE falsely identified E2/E2 phenotype. The presence of mutated ApoE was suspected on an unusual restriction polymorphism of a Hha 1 restriction site and confirmed by sequence analysis of the cloned polymerase chain reaction fragment of exon 4 and familial segregation study. The severity of the hypertriacylglycerolaemia was modulated by the lipid content of the diet. A low-fat diet enriched in medium-chain triacylglycerol (TAG) decreased but did not normalize plasma TAG levels in both affected patients of the pedigree. A standardized lipid-enriched test meal showed a marked impairment of TAG-rich lipoprotein (TRL) clearance, especially the exogeneous TRL bearing ApoB-48 which still represented 79 % of total TRL 7 h after the fat load. Finally, differences between the male and female siblings with the existence of a consanguine relationship in their parents suggested the involvement of other genetic factors in modulating the severity of phenotypic expression. This observation reinforces the usefulness of genotyping of ApoE for the characterization of genetic hypertriacylglycerolaemia and selection of the appropriate diet and treatment.

Quantitative data on phyto-oestrogen, particularly lignan, content in edible plants are insufficient. We, therefore, measured isoflavonoids and lignans in nine edible berries using an isotope dilution gas chromatography–mass spectrometry method for foods and found substantial concentrations of the lignan secoisolariciresinol (1·39–37·18 mg/kg DM), low amounts of matairesinol (0–0·78 mg/kg DM) and no isoflavones. To determine pharmacokinetics and urinary excretion pattern of the mammalian lignan enterolactone derived from plant lignans, a study with human subjects was conducted. Five healthy women and two men consumed, after a 72 h period of a phyto-oestrogen-free regimen, a single strawberry-meal containing known amounts of plant lignans. Basal and post-meal blood and urine samples were collected at short intervals. The samples were analysed using time-resolved fluoroimmunoassay of enterolactone. The meal increased plasma concentration of enterolactone after 8–24 h and in urine in the 13–24 h and 25–36 h urine collections. High individual variability of the metabolic response was observed. Enterolactone excreted in the urine collected throughout the 48 h post-meal yielded on average 114 % of the plant lignans consumed. It is concluded that berries containing relatively high concentrations of plant lignans contribute to plasma and urinary levels of mammalian enterolactone in human subjects.

In order to study the mechanism by which increasing unsaturation of dietary fat lowers HDL-cholesterol levels, we studied various measures of HDL metabolism in hamsters fed with fats with different degrees of saturation. Hamsters were fed on a cholesterol-enriched (1 g/kg) semipurified diet containing 200 g/kg of maize oil, olive oil, or palm oil for 9 weeks. Increasing saturation of dietary fat resulted in increasing concentrations of total plasma cholesterol (4·29 (SD 0·51), 5·30 (sd 0·67) and 5·58 (sd 0·76) mmol/l respectively, n 12) and HDL-cholesterol (3·31 (sd 0·50), 3·91 (sd 0·12) and 3·97 (sd 0·43) mmol/l) and these concentrations were significantly higher (P < 0·05) in the palm-oil and olive-oil-fed hamsters compared with the maize-oil group. Total plasma triacylglycerol levels also increased with increasing fat saturation (1·01 (sd 0·59), 1·56 (sd 0·65) and 2·75 (sd 1·03) mmol/l) and were significantly higher (P < 0·05) in the palm-oil group compared with the olive-oil and maize-oil-fed hamsters. The three diets did not have differential effects on plasma activity levels of lecithin: cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP). Levels of phospholipid transfer protein (PLTP) tended to be higher with increasing fat saturation but this effect was not significant. The capacity of liver membranes to bind human HDL3 was significantly higher (P < 0·05) in the hamsters fed with maize oil (810 (sd 100) ng HDL3 protein/mg membrane protein, n 4) compared with those fed on palm oil (655 (sd 56) ng/mg), whereas the olive-oil group had intermediate values (674 (sd 26) ng/mg). The affinity of HDL3 for the binding sites was not affected by the type of dietary fat. Hepatic lipase (EC 3.1.1.3) activity, measured in liver homogenates, increased with increasing fat saturation. We conclude that dietary maize oil, when compared with either olive oil or palm oil, may lower HDL-cholesterol concentrations by enhancing HDL binding to liver membranes.

Gain in body weight over a number of years could be achieved through cumulative positive energy balances. These positive balances could come about through adjustments in the various components of energy expenditure or fuel utilization, together with shifts in food selection or eating patterns leading to adjustments in macronutrient intake. This means that many combinations of intake and expenditure could lead to a positive energy balance; these combinations can be called routes to body weight gain. However, these routes are difficult to trace by studying random samples of individuals. Previous investigations have found a clear association between high fat consumption and the occurrence of obesity, and although a high fat intake is a strong behavioural risk factor for weight gain, the relationship does not constitute a biological inevitability. Some normal-weight and lean individuals appear to eat a high-fat diet. To investigate reasons for this we have studied individuals initially defined by particular clusters of dietary characteristics related to fat and carbohydrate consumption. Habitual high-fat (HF) and low-fat (LF) consumers have been termed phenotypes. Various aspects of energy expenditure (physiological and behavioural) and energy intake were measured in these individuals with contrasting profiles. HF phenotypes had high intakes of fatty foods and an overall higher energy intake than LF. However, these groups of young adult males had similar BMIs and percentage body fat. The HF had a significantly higher resting metabolic rate (RMR) and a lower RQ, together with high plasma fasting leptin levels, and a higher sleeping heart rate. In HF individuals the physical activity level was somewhat lower and they had significantly more periods of sedentary behaviour than LF subjects. Although HF individuals appear to be more vulnerable to developing obesity, both phenotypes carry particular risk factors and protective factors for weight gain. The use of phenotypes has allowed the identification of different potential routes to weight gain. Different strategies are required to prevent age-related increase in body weight in these quite different individuals.

An experiment was conducted to investigate the effects of branched-chain amino acid (BCAA) interactions on their utilization by growing pigs and the effects of excessive amounts of BCAA (leucine, isoleucine, valine) on the utilization of methionine. A semipurified diet containing 100 g crude protein/kg with a balanced amino acid pattern was prepared using casein supplemented with free amino acids. Three further diets were made by reducing the concentration of methionine + cyst(e)ine, valine or isoleucine by 20 %. Each of these four diets was then supplemented with leucine (50 % excess) or a mixture of BCAA (50 % excess of each but excluding the limiting amino acid). All diets were isoenergetic and were made isonitrogenous by replacement of glutamic and aspartic acids. The twelve diets were given to twenty-four growing pigs (30–40 kg) in three periods according to a randomized block design. Each period lasted 8 d and N retention was measured during the last 5 d of each period. Reducing dietary methionine, valine or isoleucine reduced the utilization of N (N retained/N digested) by approximately 20 % (P < 0·05). Adding leucine to the isoleucine-limiting diet decreased the utilization of N by 9 % (P < 0·05). This was reversed by simultaneous addition of valine. Excess leucine in a valine-deficient diet did not significantly reduce N utilization. In methionine-limiting diets an excess of either leucine alone or of all three BCAA increased the utilization of N by 8 % (P < 0·05).

To explore the nutritional significance of urea hydrolysis for human subjects, male infants being treated for severe undernutrition were given oral doses of 10 mg [15N15N]urea every 3 h for 36 h, on admission, during rapid growth and after repletion with either moderate or generous intakes of protein. Urea hydrolysis was calculated from the 15N enrichment of urinary urea, and where possible, lysine, alanine, glycine and histidine were isolated from urine by preparative ion-exchange chromatography for measurement of 15N enrichment. Sufficient N was obtained for 15N enrichment of lysine to be measured on fifteen occasions from six children. Urea hydrolysis accounted for half of all urea production with 130 (sd 85) mg N/kg hydrolysed per d, most of which appeared to be utilized in synthetic pathways. Of the samples analysed successfully, nine samples of lysine were enriched with 15N (mean atom percent excess 0·0102, range 0·0017–0·0208) with relative enrichment ratios with respect to lysine of 1·63 (range 0·18–3·15), 1·96 (range 0·7–3·73) and 0·9 (range 0·4–1·8) for glycine, alanine and histidine respectively. Enriched samples were identified at each treatment phase and 68 % of the variation in lysine enrichment was explained by the variation in urea enrichment with 54 % explained by the overall rate of delivery of 15N to the lower gastrointestinal tract. The results indicate a minimum of 4·7 mg lysine per kg body weight made available by de novo synthesis with the more likely value an order of magnitude higher. Thus, urea hydrolysis can improve the quality of the dietary protein supply by enabling an increased supply of lysine and other indispensable amino acids.To explore the nutritional significance of urea hydrolysis for human subjects, male infants being treated for severe undernutrition were given oral doses of 10 mg [15N15N]urea every 3 h for 36 h, on admission, during rapid growth and after repletion with either moderate or generous intakes of protein. Urea hydrolysis was calculated from the 15N enrichment of urinary urea, and where possible, lysine, alanine, glycine and histidine were isolated from urine by preparative ion-exchange chromatography for measurement of 15N enrichment. Sufficient N was obtained for 15N enrichment of lysine to be measured on fifteen occasions from six children. Urea hydrolysis accounted for half of all urea production with 130 (sd 85) mg N/kg hydrolysed per d, most of which appeared to be utilized in synthetic pathways. Of the samples analysed successfully, nine samples of lysine were enriched with 15N (mean atom percent excess 0·0102, range 0·0017–0·0208) with relative enrichment ratios with respect to lysine of 1·63 (range 0·18–3·15), 1·96 (range 0·7–3·73) and 0·9 (range 0·4–1·8) for glycine, alanine and histidine respectively. Enriched samples were identified at each treatment phase and 68 % of the variation in lysine enrichment was explained by the variation in urea enrichment with 54 % explained by the overall rate of delivery of 15N to the lower gastrointestinal tract. The results indicate a minimum of 4·7 mg lysine per kg body weight made available by de novo synthesis with the more likely value an order of magnitude higher. Thus, urea hydrolysis can improve the quality of the dietary protein supply by enabling an increased supply of lysine and other indispensable amino acids.To explore the nutritional significance of urea hydrolysis for human subjects, male infants being treated for severe undernutrition were given oral doses of 10 mg [15N15N]urea every 3 h for 36 h, on admission, during rapid growth and after repletion with either moderate or generous intakes of protein. Urea hydrolysis was calculated from the 15N enrichment of urinary urea, and where possible, lysine, alanine, glycine and histidine were isolated from urine by preparative ion-exchange chromatography for measurement of 15N enrichment. Sufficient N was obtained for 15N enrichment of lysine to be measured on fifteen occasions from six children. Urea hydrolysis accounted for half of all urea production with 130 (sd 85) mg N/kg hydrolysed per d, most of which appeared to be utilized in synthetic pathways. Of the samples analysed successfully, nine samples of lysine were enriched with 15N (mean atom percent excess 0·0102, range 0·0017–0·0208) with relative enrichment ratios with respect to lysine of 1·63 (range 0·18–3·15), 1·96 (range 0·7–3·73) and 0·9 (range 0·4–1·8) for glycine, alanine and histidine respectively. Enriched samples were identified at each treatment phase and 68 % of the variation in lysine enrichment was explained by the variation in urea enrichment with 54 % explained by the overall rate of delivery of 15N to the lower gastrointestinal tract. The results indicate a minimum of 4·7 mg lysine per kg body weight made available by de novo synthesis with the more likely value an order of magnitude higher. Thus, urea hydrolysis can improve the quality of the dietary protein supply by enabling an increased supply of lysine and other indispensable amino acids.To explore the nutritional significance of urea hydrolysis for human subjects, male infants being treated for severe undernutrition were given oral doses of 10 mg [15N15N]urea every 3 h for 36 h, on admission, during rapid growth and after repletion with either moderate or generous intakes of protein. Urea hydrolysis was calculated from the 15N enrichment of urinary urea, and where possible, lysine, alanine, glycine and histidine were isolated from urine by preparative ion-exchange chromatography for measurement of 15N enrichment. Sufficient N was obtained for 15N enrichment of lysine to be measured on fifteen occasions from six children. Urea hydrolysis accounted for half of all urea production with 130 (sd 85) mg N/kg hydrolysed per d, most of which appeared to be utilized in synthetic pathways. Of the samples analysed successfully, nine samples of lysine were enriched with 15N (mean atom percent excess 0·0102, range 0·0017–0·0208) with relative enrichment ratios with respect to lysine of 1·63 (range 0·18–3·15), 1·96 (range 0·7–3·73) and 0·9 (range 0·4–1·8) for glycine, alanine and histidine respectively. Enriched samples were identified at each treatment phase and 68 % of the variation in lysine enrichment was explained by the variation in urea enrichment with 54 % explained by the overall rate of delivery of 15N to the lower gastrointestinal tract. The results indicate a minimum of 4·7 mg lysine per kg body weight made available by de novo synthesis with the more likely value an order of magnitude higher. Thus, urea hydrolysis can improve the quality of the dietary protein supply by enabling an increased supply of lysine and other indispensable amino acids.

Previous epidemiological studies have demonstrated relationships between individual nutrients and glucose intolerance and type 2 diabetes, but the association with the overall pattern of dietary intake has not previously been described. In order to characterize this association, 802 subjects aged 40–65 years were randomly selected from a population-based sampling frame and underwent a 75 g oral glucose-tolerance test. Principal component analysis was used to identify four dietary patterns explaining 31·7 % of the dietary variation in the study cohort. These dietary patterns were associated with other lifestyle factors including socio-economic group, smoking, alcohol intake and physical activity. Component 1 was characterized by a healthy balanced diet with a frequent intake of raw and salad vegetables, fruits in both summer and winter, fish, pasta and rice and low intake of fried foods, sausages, fried fish, and potatoes. This component was negatively correlated with central obesity, fasting plasma glucose, 120 min non-esterified fatty acid and triacylglycerol, and positively correlated with HDL-cholesterol. It therefore appears to be protective for the metabolic syndrome. Component 1 was negatively associated with the risk of having undiagnosed diabetes, and this association was independent of age, sex, smoking and obesity. The findings support the hypothesis that dietary patterns are associated with other lifestyle factors and with glucose intolerance and other features of the metabolic syndrome. The results provide further evidence for the recommendation of a healthy balanced diet as one of the main components of chronic disease prevention.

There is evidence that food consistency may influence postprandial physiological responses. Recently we found that homogenization of a vegetable-rich meal significantly delayed the gastric emptying rate and was more satiating than the same meal in solid–liquid form. In this present study we investigated whether homogenization also influences endocrine and metabolic responses to the meal. Eight healthy men, aged 21–28 (mean 24·5) years, were given the meal (cooked vegetables 250 g, cheese 35 g, croutons 50 g and olive oil 25 g, with water 300 ml; total energy 2·6 MJ) in both solid–liquid (SM) and homogenized (HM) form, in random order, at 1-week intervals. Variables assayed were plasma glucose, insulin and glucose-dependent insulinotropic peptide (GIP) levels for 2 h and diet-induced thermogenesis (DIT) for 5 h. Plasma glucose pattern was similar after both meals. However, HM induced significantly greater insulin, GIP and DIT responses than SM. Mean integrated areas under the curves (AUC) were 1·7 (SEM 0·38) V. 1·2 (sem 0·33) U/l per 120 min (P = 0·005) for insulin, 19·9 (sem 2·44) v. 16 (sem 1·92) nmol/l per 120 min (P = 0·042) for GIP, and 237·7 (sem 16·32) v. 126·4 (sem 23·48) kJ/300 min (P = 0·0029) for DIT respectively. Differences between GIP-AUC after HM and SM correlated significantly with differences between insulin-AUC after HM and SM (r2 0·62, P = 0·021). These findings demonstrate that homogenization of a meal results in a coordinated series of changes of physiological gastroentero–pancreatic functions and confirm that the physical state of the meal plays an important role in modulating endocrine and metabolic responses to food.

Four ewes, each fitted with a rumen cannula and with catheters in the mesenteric artery and portal and mesenteric veins, received continuous intrarumen infusions of water or of short-chain fatty acids (SCFA). SCFA infusions were isoenergetic (83 kJ/h) and provided rumen molar proportions (acetate : propionate : butyrate) of 70 : 20 : 10, 50 : 40 : 10 or 50 : 20 : 30. The rumen SCFA production rate with the basal diet was 90·0, 23·1 and 8·8 mmol/h for acetate, propionate and butyrate respectively. Portal net fluxes indicated that 74, 67 and 22–30 % of infused acetate, propionate and butyrate respectively, reached the portal vein. Portal net release of β-hydroxybutyrate increased with SCFA infusions, irrespective of the amount of butyrate infused. Portal net release of lactate decreased with high-butyrate infusion. Portal net uptake of glucose increased with the SCFA infusions. In ewes infused with water, a portal net uptake of total amino acids (AA) was observed. SCFA infusions decreased the uptake of nonessential AA (glutamate, glycine, but not glutamine) and increased the net release of tyrosine and essential AA (isoleucine, leucine). Portal net fluxes of AA were similar with both high-acetate and high-propionate infusions. Lower net uptake of glutamine and net release of most essential AA and some nonessential AA were observed with the high-butyrate infusion. Energetic summation of portal net release was not significantly different between the three SCFA infusions, although it tended to be lower with high-butyrate infusion. This may be related to the higher trophic effect of butyrate on the digestive mucosa.

The clustering of cardiovascular risk factors such as abdominal obesity, hypertension, dyslipidaemia and glucose intolerance in the same persons has been called the metabolic or insulin-resistance syndrome. In 1998 WHO proposed a unifying definition for the syndrome and chose to call it the metabolic syndrome rather than the insulin-resistance syndrome. Although insulin resistance has been considered as a common denominator for the different components of the syndrome, there is still debate as to whether it is pathogenically involved in all of the different components of the syndrome. Clustering of the syndrome in families suggests a genetic component. It is plausible that so-called thrifty genes, which have ensured optimal storage of energy during periods of fasting, could contribute to the phenotype of the metabolic syndrome. Common variants in a number of candidate genes influencing fat and glucose metabolism can probably, together with environmental triggers, increase susceptibility to the syndrome. Among these, the genes for β3-adrenergic receptor, hormone-sensitive lipase, lipoprotein lipase, IRS-1, PC-1, skeletal muscle glycogen synthase, etc. appear to increase the risk of the metabolic syndrome. In addition, novel genes may be identified by genome-wide searches.

The usefulness of supplementary dietary L-CARNITINE AS AN IMMUNOMODULATOR TO INCREASE ANTIGEN-SPECIFIC ANTIBODY LEVELS WAS ANALYSED IN 2–6-WEEK-OLD BROILERS. THE CHICKENS RECEIVED COMMERCIAL FEEDS EITHER UNSUPPLEMENTED (STARTER FEED 17·8 MG CARNITINE/KG, FINISHER DIET 22·9 MG CARNITINE/KG) OR SUPPLEMENTED WITH l-carnitine (100 mg carnitine/kg added to feed). At 14 d of age, both groups were distributed in equal numbers and sex ratios over two environmentally controlled chambers where temperature (28°) was either reduced immediately to 20°, or gradually to 22° at 36 d of age. Antigen-specific immunoglobulin (Ig)M, IgG, IgA and total Ig responses were measured following two immunizations with bovine serum albumin (BSA). The typical BSA-specific IgM responses followed by IgG responses to the primary immunization were boosted by the secondary immunization. The kinetics of these responses were not altered by l-carnitine treatment. However, BSA-specific total Ig and IgG, but not IgM, responses were significantly increased by dietary l-carnitine supplementation, after both the primary and the secondary immunization. No significant influence of the sex of the chicks or the imposed environmental temperature on Ig responses was found. Temperature treatment and sex, but not l-carnitine supplementation, did significantly influence body-weight gain: cockerels were heavier than females and this became most evident in the second half of the rearing period. Further, lowering the temperature increased body weight. In conclusion, dietary l-carnitine supplementation appeared to be beneficial in enhancing specific humoral responses on vaccination.

Randomized controlled trials of the effects of the dietary supplement Efacal® (Scotia Pharmaceuticals Plc, Guildford, Surrey, UK) v. Ca only on total body bone mineral density (BMD) and markers of bone turnover were conducted in healthy pre- and postmenopausal women separately. Total daily dose for 12 months for the Efacal® groups was: Ca 1·0 g, evening primrose oil 4·0 g and marine fish oil 440 mg; and for the control groups was: Ca 1·0 g. Reported compliance was better than 90 % in both age groups. For the forty-three premenopausal women (age range 25–40 years), initial mean total body BMD values were similar for Efacal® and control groups and both groups showed highly significant mean increases of about 1 %; however, there were no significant between-group differences for the changes in BMD or markers of bone turnover. For the forty-two postmenopausal women (age range 50–65 years), initial mean total body BMD values were again well-matched across treatment groups. Both Efacal® and control groups showed highly significant decreases in total body BMD of about 1 %, but again there were no significant between-group differences in total body BMD or markers of bone turnover. Possible confounding variables such as initial total body BMD were explored but had no effect on the outcome in either age group. Nail quality improved in both age groups and in both Efacal® and control groups. Again, there was no significant difference between treatment groups. No evidence was found to support a beneficial effect of Efacal® on BMD in these women.

Type 2 diabetes is commoner in Asians than Caucasians. Many nitrosamines are diabetogenic, causing both type 2 and type 1 diabetes. Of CD1 mice fed with betel-nut or associated nitrosamines 8·5 % develop glucose intolerance with marked obesity. Glycaemia and anthropometric risk markers for type 2 diabetes were therefore examined in relation to betel usage in 993 ‘healthy’ Bangladeshis by one bilingual research-worker (N.M.). Of these, 12 % had known diabetes. A further 145 of 187 subjects ‘at-risk’ of diabetes (spot glucose >6·5 mmol/l <2 h after food, or >4·5 mmol/l >2 h after food) had a second blood glucose sample taken; sixty-one were confirmed as ‘at-risk’, and had an oral glucose tolerance test; nine new diabetics were identified. Multiple regression analysis showed that spot blood glucose values decreased with time after eating (P = 0·0005) and increased independently with waist size (P = 0·0005) and age (P = 0·0005) without relationships to other aspects of the diet, season or smoking. Waist size was strongly related to betel usage independent of other factors such as age. Betel use interacted with sex, relating to increasing glycaemia only in females. Since waist and age were the major markers of increasing glycaemia we suggest that betel chewing, a habit common to about 10 % of the world population (more than 200 million people) may contribute to the risk of developing type 2 diabetes mellitus.

This paper reports the compilation of a food composition database for phylloquinone (vitamin K1) derived from the direct analysis of foods, recipe calculation and the assignment of values based on food similarities. All the basic and other food items used in these calculations had been analysed by HPLC and about 170 of the items had been obtained and assayed in the UK. Recipe calculations took account of the cooking method and changes in water and fat content. Currently, approximately 1501 food items with Royal Society of Chemistry/Ministry of Agriculture, Fisheries and Food food codes have been allocated a vitamin K1 value, and a further 282 new recipe codes are included in the database. Representative values from each food group are reported together with an indication of the potential variation. Detailed examples of some recipe calculations are included, and also the impact of changing the type of fat in recipes. Vitamin K1 is associated with, and most abundant in, photosynthetic tissues of plants. Accordingly, the highest concentrations (3000–6000 μg/kg) are found in dark-green leafy vegetables and herbs, such as kale, parsley, spinach and green cabbage. Intermediate concentrations (1000–2000 μg/kg) are found in plants with paler leaves such as white cabbage and lettuce or in green, non-leafy vegetables such as broccoli and brussel sprouts. Fats and oils contain variable amounts of vitamin K1 with the highest concentrations (300–1300 μg/kg) in soyabean, rapeseed and olive oils and the margarines based on them. Other foods such as dairy products, meat dishes and cereal-based foods (bread, biscuits, cakes, desserts etc.), although not in themselves particularly rich in vitamin K1 (< 200 μg/kg), may contribute significantly to intakes when consumption of green vegetables is poor. Within the scope of this present study, it has not been possible to address issues such as inter-sample variability, losses during storage or the bioavailability from different foods and further work on these aspects is needed.

The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30–35 kg) were prepared with arterial catheters. After recovery, they received for 7 d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16 h postabsorptive) and after the morning meal (4 h postprandial). The animals were then divided into three groups and received for a further 7 d a methionine-limiting diet (80 % of requirement) (1) without any amino acid excess; (2) with excess leucine (50 % over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50 % over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0·05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0·05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0·05) increased by excesses of leucine or all BCAA.

The ratio plasma retinol-binding protein (RBP) : transthyretin (TTR) has been proposed as a means to improve the assessment of vitamin A status of individuals with concurrent infection or inflammation. We have measured RBP and TTR in stored sera from South African children who had accidentally ingested kerosene. Samples were collected from these children in hospital when suffering acute inflammation and respiratory distress, and from them and neighbourhood control children 3 months later. Vitamin A status was defined by modified relative dose response (MRDR) tests of liver retinol stores at 3 months and by serum retinol concentration both when children were ill and when they were well. Illness was defined as either being in hospital or, at follow-up, as having a raised plasma α1-acid glycoprotein (AGP) level. The RBP : TTR value was significantly decreased by both illness and low liver retinol stores. When the effects on RBP : TTR of illness and vitamin A stores were considered together for the 3-month follow-up samples, only vitamin A status significantly decreased the value. We calculated sensitivity and specificity of the RBP : TTR ratio against established measures of vitamin A status using a cut-off value of 0·3 for RBP : TTR and standard cut-off values for MRDR (0·06) and plasma retinol (0·7 μmol/l). Compared with MRDR, RBP : TTR had sensitivities of 76 % and 43 % and specificities of 22 % and 81 % to detect vitamin A deficiency in hospitalized and well children respectively. Compared with plasma retinol, sensitivities were 88 % and 44 % and specificities were 55 % and 64 % in hospitalized and well children respectively. Only for the case of clinically well children with biochemical evidence of subclinical inflammation did sensitivity (62 % and 100 % against MRDR and plasma retinol respectively) and specificity (100 % and 60 % against MRDR and retinol) approach useful levels for an assessment tool. Overall, although a trend supporting the theory behind the use of the RBP : TTR for assessment of vitamin A status in infection was observed in the current study, the ratio did not provide adequate sensitivity and specificity to be a useful assessment tool.

To gain an understanding of UK consumer attitudes and beliefs regarding starchy foods and their dietary role, a questionnaire based on the theory of planned behaviour was developed and sent out to a UK consumer sample (n 800). The content focused on attitudes and beliefs towards starchy foods, perceived barriers towards increasing their intake (e.g. cost, habit, social influences), perceptions of personal and recommended starchy food intake, intention to increase starchy food intakes in the future and socio-demographic information. Responses (n 414) indicated that consumers have highly divergent attitudes and beliefs regarding starchy foods. These foods are seen as nutritious and good for one's health, but also as high in energy and not helping to control weight, and the overall intention to increase starchy food intake was extremely low. Possible barriers towards increasing starchy food intake were the perceptions that personal starchy food intakes were already high, beliefs that starchy food intakes should be reduced to achieve a healthier diet, and the view that personal starchy food intakes did not need to be changed any further, because (depending on attitude) individual's intakes had already been increased or reduced. The model including attitude and subjective norm had the best fit for predicting reported intention to increase starchy food consumption, with attitude being the strongest contributor. Addition of the factor ‘family's liking of starchy foods’ significantly improved the model. For reported starch intake, the model including attitude had the best fit, and addition of other factors did not improve the model. These findings indicate that health promotion strategies aimed at increasing complex carbohydrate intakes should take these perceptions into consideration; however, further work is required to examine how these potential barriers can best be addressed in practice.

Rumen microbial degradation is an important route for detoxification of secondary plant compounds encountered in the diets of free-grazing ruminants. Exposure to diets containing particular secondary plant compounds can lead to increased rates of secondary compound degradation in the rumen. An experiment was conducted to determine whether rumen adaptation to oxalic acid would influence the diet selection of goats offered choices between plant species differing in their oxalic acid content. Twelve adult female goats were divided into two groups of six animals each. One group received a daily oral dose, in gelatin capsules, of 0·6 mmol oxalic acid/kg live weight per d throughout the experiment while the other group received placebos consisting of empty gelatin capsules. After an adaptation period of 8 d, the animals were allowed to graze a mixture of spinach (rich in oxalic acid) and cabbage (low in oxalic acid) for 7 h/d on two consecutive days per week during four consecutive 1-week periods. Intervening days were spent on grass pasture. Diet composition and intake were measured using cuticular wax n−alkanes as internal markers. Results showed that adapted goats included a higher proportion of spinach in their diet (P < 0·05) although absolute intakes of spinach were the same for the two groups. Goats in the oxalic-acid-adapted group consumed less cabbage than control animals (P < 0·05) suggesting that adaptation to oxalic acid at the rumen level may have interfered with detoxification of cabbage-derived secondary plant compounds. Voluntary intake increased progressively through the four experimental periods (P < 0·001) with a tendency for higher intakes among control than among adapted animals (P < 0·1). The experiment demonstrates how differences in the rate of degradation of secondary plant compounds may influence diet selection in ruminants.

In order to study the mechanism by which increasing unsaturation of dietary fat lowers HDL-cholesterol levels, we studied various measures of HDL metabolism in hamsters fed with fats with different degrees of saturation. Hamsters were fed on a cholesterol-enriched (1 g/kg) semipurified diet containing 200 g/kg of maize oil, olive oil, or palm oil for 9 weeks. Increasing saturation of dietary fat resulted in increasing concentrations of total plasma cholesterol (4·29 (SD 0·51), 5·30 (sd 0·67) and 5·58 (sd 0·76) mmol/l respectively, n 12) and HDL-cholesterol (3·31 (sd 0·50), 3·91 (sd 0·12) and 3·97 (sd 0·43) mmol/l) and these concentrations were significantly higher (P < 0·05) in the palm-oil and olive-oil-fed hamsters compared with the maize-oil group. Total plasma triacylglycerol levels also increased with increasing fat saturation (1·01 (sd 0·59), 1·56 (sd 0·65) and 2·75 (sd 1·03) mmol/l) and were significantly higher (P < 0·05) in the palm-oil group compared with the olive-oil and maize-oil-fed hamsters. The three diets did not have differential effects on plasma activity levels of lecithin: cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP). Levels of phospholipid transfer protein (PLTP) tended to be higher with increasing fat saturation but this effect was not significant. The capacity of liver membranes to bind human HDL3 was significantly higher (P < 0·05) in the hamsters fed with maize oil (810 (sd 100) ng HDL3 protein/mg membrane protein, n 4) compared with those fed on palm oil (655 (sd 56) ng/mg), whereas the olive-oil group had intermediate values (674 (sd 26) ng/mg). The affinity of HDL3 for the binding sites was not affected by the type of dietary fat. Hepatic lipase (EC 3.1.1.3) activity, measured in liver homogenates, increased with increasing fat saturation. We conclude that dietary maize oil, when compared with either olive oil or palm oil, may lower HDL-cholesterol concentrations by enhancing HDL binding to liver membranes.