Most New Zealand soils contain relatively low concentrations of the anionic trace elements F, I and Se. Some areas of Australia also have a history of I deficiency. In view of current interest in establishing nutrient reference intakes for Se and I in New Zealand and Australia, it is timely to review current understanding of the intakes and status of these two elements. In spite of a recent increase in Se status, the status of New Zealanders remains low compared with populations of many other countries and may still be considered marginal, although the clinical consequences of the marginal Se status are unclear. There are no recent reports of blood Se levels in Australia, but earlier reports indicate that they were generally greater than those of New Zealanders. Similarly, the consequences of decreasing I status in Australia and New Zealand are unclear. Mild I deficiency in New Zealand has resulted in enlarged thyroid glands indicating an increased risk of goitre. Currently there is little evidence, however, of any associated clinical disease. Public health recommendations to reduce salt intake, together with the reduction in I content of dairy products, are likely to result in further decreases in the I status of New Zealand and Australian residents. Some action is needed to prevent this decline and it may be necessary to consider other means of fortification than iodized salt. The consequences of possible interactions between Se and I in human nutrition are also unclear and no practical recommendations can be made.

The use of transgenic crops as feeds for ruminant animals has prompted study of the possible uptake of transgene fragments by ruminal micro-organisms and/or intestinal absorption of fragments surviving passage through the rumen. The persistence in buffered ruminal contents of seven different recombinant DNA fragments from GM rapeseed expressing the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) transgene was tracked using PCR. Parental and transgenic (i.e. glyphosphate-tolerant; Roundup Ready®, Monsanto Company, St Louis, MO, USA) rapeseed were incubated for 0, 2, 4, 8, 12, 24 and 48 h as whole seeds, cracked seeds, rapeseed meal, and as pelleted, barley-based diets containing 65 g rapeseed meal/kg. The seven transgene fragments ranged from 179 to 527 bp and spanned the entire 1363 bp EPSPS transgene. A 180 bp ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit fragment and a 466 bp 16S rDNA fragment were used as controls for endogenous rapeseed DNA and bacterial DNA respectively. The limit of detection of the PCR assay, established using negative controls spiked with known quantities of DNA, was 12·5 pg. Production of gas and NH3 was monitored throughout the incubation and confirmed active in vitro fermentation. Bacterial DNA was detected in all sample types at all time points. Persistence patterns of endogenous (Rubisco) and recombinant (EPSPS) rapeseed DNA were inversely related to substrate digestibility (amplifiable for 48, 8 and 4 h in whole or cracked seeds, meal and diets respectively), but did not differ between parental and GM rapeseed, nor among fragments. Detection of fragments was representative of persistence of the whole transgene. No EPSPS fragments were amplifiable in microbial DNA, suggesting that transformation had not occurred during the 48 h incubation. Uptake of transgenic DNA fragments by ruminal bacteria is probably precluded or time-limited by rapid degradation of plant DNA upon plant cell lysis.

The majority of the studies that have found a lowering effect of exercise on postprandial lipaemia have employed exercise 12–18 h before a test meal of exaggerated fat content (over 60 % total energy). The aim of the present study was to investigate whether this effect is manifest when exercise is performed immediately before a test meal of moderate fat content. Eleven healthy young men cycled for 45 min at 62 % maximal heart rate or rested, and, immediately afterwards, consumed a meal of moderate fat content (35 % total energy, 0·65 g/kg body mass) in a random counterbalanced design. Blood samples were drawn before exercise, before the meal, and for 8 h postprandially. No significant differences were observed in plasma triacylglycerol concentrations and areas under the triacylglycerol concentration v. time curves between exercise and rest, although exercise reduced the postprandial lipaemic response by 17 %. Non-esterified fatty acids, glucose, and insulin did not differ significantly between the trials. In conclusion, moderate exercise performed immediately before a meal of a fat content typical to the Western diet had only a modest effect on postprandial lipaemia.

The importance of legume proteins in cholesterol metabolism has been recognised, but the hindgut contribution is still unclear. The present work was undertaken to address the role of the caecum–colon in cholesterol metabolism in intact (I) and ileo-rectal anastomosed (IRA) pigs fed with casein or extruded soyabean (ES) diets. Four groups of six growing pigs were assigned to the treatments (casein–I, casein–IRA, ES–I, ES–IRA) for 3 weeks. Plasma total cholesterol, LDL- and HDL-cholesterol were not modified by surgery or diet. In the liver, the ES diet significantly depressed non-esterified, esterified and total cholesterol. The treatments did not affect hepatic 3-hydroxy-3-methylglutaryl CoA reductase, cholesterol 7α-hydroxylase or sterol 27-hydroxylase activities. In the gallbladder bile of ES-fed pigs, total cholesterol was depressed while total bile acid concentration was increased. IRA and the ES diet markedly decreased the biliary bile acid microbial metabolites (namely hyodeoxycholic acid) and increased the primary bile acids (mainly hyocholic acid). The concentration of bile hydrophobic acids was decreased only by the ES diet. Faecal neutral sterol output was increased in ES-fed pigs, but the bile acid and the sum of neutral and acidic steroid outputs were not. Microbial transformation of neutral and acidic steroids was markedly reduced by IRA, especially in the ES-fed pigs. Thus, surgery and ES modulated the steroid profile but the caecum–colon did not seem to play a crucial role in determining cholesterolaemia in pigs.

Factors affecting absorption of physiological doses of vitamin C in man have not been widely studied, partly because few suitable tools exist to distinguish recently absorbed vitamin C from endogenous vitamin. Stable isotope-labelled vitamin C provides such a tool. Fifteen healthy non-smoking subjects aged 26–59 years were studied. Each received 30 mg L-[1-13C]ascorbic acid orally on two occasions, 3–4 weeks apart. The ascorbate was given alone or with Fe (100 mg as ferrous fumarate) or with red grape juice, which is rich in polyphenols. Blood was collected at frequent intervals for 1 h, and then each hour for a further 3 h. Total concentration of vitamin C was measured fluorometrically and its 13C-isotope enrichment was measured by GC–MS after conversion to volatile trimethylsilyl esters. Peak plasma enrichment occurred within 25–50 min. No kinetic variables were significantly altered by the iron fumarate supplement. Grape juice attenuated vitamin C absorption, reaching significance at the 20 min time point. There were weak correlations between isotope enrichment and body weight or endogenous ascorbate concentration. The increment in total plasma ascorbate was smaller if calculated from isotope enrichment than from vitamin C concentration increase. The dilution pool was much larger than the plasma ascorbate pool. Further studies are needed to resolve these paradoxes. Stable isotope-labelled ascorbate is potentially useful for measurement of vitamin C absorption by human subjects.

Age-related macular degeneration (AMD) is one of the most common eye diseases of elderly individuals. It has been suggested that lutein and zeaxanthin may reduce the risk for AMD. Information concerning the absorption of non-esterified or esterified zeaxanthin is rather scarce. Furthermore, the formation pathway of meso (3R,3′S)-zeaxanthin, which does not occur in plants but is found in the macula, has not yet been identified. Thus, the present study was designed to assess the concentration of 3R,3R′-zeaxanthin reached in plasma after the consumption of a single dose of native 3R,3′R-zeaxanthin palmitate from wolfberry (Lycium barbarum) or non-esterified 3R,3′R-zeaxanthin in equal amounts. In a randomised, single-blind cross-over study, twelve volunteers were administered non-esterified or esterified 3R,3′R-zeaxanthin (5 mg) suspended in yoghurt together with a balanced breakfast. Between the two intervention days, a 3-week depletion period was inserted. After fasting overnight, blood was collected before the dose (0 h), and at 3, 6, 9, 12, and 24 h after the dose. The concentration of non-esterified 3R,3′R-zeaxanthin was determined by chiral HPLC. For the first time, chiral liquid chromatography–atmospheric pressure chemical ionisation-MS was used to confirm the appearance of 3R,3′R-zeaxanthin in pooled plasma samples. Independent of the consumed diet, plasma 3R,3′R-zeaxanthin concentrations increased significantly (P=0·05) and peaked after 9–24 h. Although the concentration curves were not distinguishable, the respective areas under the curve were distinguishable according to a two-sided F and t test (P=0·05). Thus, the study indicates an enhanced bioavailability of 3R,3′R-zeaxanthin dipalmitate compared with the non-esterified form. The formation of meso-zeaxanthin was not observed during the time period studied.

Dietary fibre and fat affect colonic tumourigenesis and inflammation. Sphingomyelin metabolism may have implications for the pathogenesis of colonic tumours and ulcerative colitis. The present study examined the effects of psyllium and fat on the enzymes responsible for sphingomyelin metabolism and apoptosis in the colon. Mice were fed control, psyllium-containing (100 g/kg), high-fat (313 g/kg, 53 % energy as fat) or high-fat plus psyllium diets for 4 weeks. The activities of acid, neutral and alkaline sphingomyelinase (SMase), neutral ceramidase, and caspase 3, 8 and 9 in colonic mucosa were determined. The expressions of alkaline SMase and caspase 3 were examined. The psyllium-containing diet was found to increase significantly the activities of alkaline SMase and caspase 3 and decreased those of acid SMase and neutral ceramidase. The high-fat diet had opposite effects on these enzymes and attenuated the effects of psyllium. Western blotting showed that psyllium increased and high-fat decreased the levels of alkaline SMase and caspase 3 in colonic mucosa. The change in caspase 3 activity was positively correlated with that of alkaline SMase and negatively with acid SMase. No similar changes of acid and alkaline phosphatase activities in the colon or acid and neutral SMase activity in the liver were identified. In conclusion, colonic sphingomyelin metabolism and apoptosis were affected by psyllium and fat in an opposite manner. The results may have implications for colorectal tumourigenesis and inflammation.

While allergic reactions to soya are increasingly investigated, the normal immune response to ingested soya is scarcely described. In the present study, we wanted to characterise the soya-specific immune response in healthy mice ingesting soya protein. Mice fed a soya-containing diet (F0) and mice of the first (F1) and second (F2) offspring generation bred on a soya protein-free diet were used either directly or were transferred between the soya-containing and soya protein-free diet during pregnancy or neonatal life. The mice were compared as to levels of naturally occurring specific antibodies analysed by ELISA, and to the presence of oral tolerance detected as a suppressed antibody and cell-proliferation response upon immunisation with soya protein. F0 mice generated soya-specific antibodies, while oral tolerance to the same soya proteins was also clearly induced. When F0 dams were transferred to soya protein-free feed before mating, the F1 and F2 offspring generations showed no significantly different response, indicating that soya-specific immune components were not maternally transmitted. However, the ingestion of dietary soya protein by F1 mice during late pregnancy and lactation caused a lasting antibody response in the offspring, but in this case in the absence of oral tolerance. This indicates that, under certain conditions, factors involved in spontaneous antibody production can be transmitted from mother to offspring. Understanding the immune response to soya protein ingested under healthy conditions is important in the assessment of adverse effects of soya protein and in the use of animal allergy models. The present results add to this understanding.

Our laboratory has reported that n-3 PUFA can reduce host resistance to Listeria infection, in part, by impairing in vivo IL-12 biosynthesis. Recently, PUFA were shown to be ligands for PPAR, a novel family of nuclear receptors with three isoforms: PPARα, PPARδ/β and PPARγ. PPARγ is expressed in immune cells, such as T cells and macrophages. Two PPARγ agonists, 15-deoxy-Δ12,14-prostaglandin (PG) J2 and rosiglitazone, have been shown to have immunomodulatory activity in vitro, including inhibiting IL-12 biosynthesis. We hypothesized that n-3 PUFA inhibit IL-12 production through activating PPARγ. We used thioglycolate-elicited mouse peritoneal macrophages to study the effect of various fatty acids and their oxidized metabolites on in vitro IL-12 production. Our present results demonstrate that both n-3 and n-6 PUFA can reduce in vitro IL-12 biosynthesis, though less potently than 15-deoxy-PGJ2 and rosiglitazone. GW9662, a PPARγ antagonist, reversed the inhibitory effect of rosiglitazone, but not that of PUFA. Our present findings suggest that fatty acid-mediated inhibition of IL-12 production is independent of PPARγ.

The objective of the present study was to investigate the time course for recovery of lymphoid tissue and T cell subset numbers when Zn-deficient (ZD) or energy-restricted (ER) rats were repleted with control diet; in a second experiment, the link between the stress axis and lymphoid organs was explored. During the deficiency phase, rats were fed a ZD (<1 mg Zn/kg) or control diet (30 mg Zn/kg, nutritionally complete) either as pair-fed controls (ER) or ad libitum-fed controls (CTL) for 3 weeks. During the repletion phase, all rats were fed control diet ad libitum for 3, 7 or 23 d. After the deficiency phase, ZD and ER had lower T cell subset numbers in the thymus compared with CTL, and ZD had reduced T cell subset numbers in the spleen compared with both ER and CTL. T cell subset numbers and lymphoid organ weights recovered from dietary Zn deficiency and energy restriction by 7 d of repletion (except 23 d for thymus weight in ZD), while body weight required more than 23 d for recovery. At the end of the deficiency phase, ZD and ER had higher circulating corticosterone concentrations compared with CTL; plasma TNFα was not detectable and there were no differences in plasma haptoglobin, an acute-phase protein. In conclusion, Zn deficiency and energy restriction elevated circulating corticosterone and reduced T cell subset numbers in the thymus and spleen of growing rats. Repletion with a nutritionally complete diet allowed recovery of T cell subset numbers and lymphoid organ weight.

The human pathogen Escherichia coli O157:H7 is thought to be spread by direct or indirect contact with infected animal or human faeces. The present study investigated the effects of the plant coumarin esculin and its aglycone esculetin on the survival of a strain of E. coli O157 under gut conditions. The addition of these compounds to human faecal slurries and in vitro continuous-flow fermenter models simulating conditions in the human colon and rumen caused marked decreases in the survival of an introduced strain of E. coli O157. When four calves were experimentally infected with E. coli O157 and fed esculin, the pathogen was detected in five of twenty-eight (18 %) of faecal samples examined post-inoculation, compared with thirteen of thirty-five (37 %) of faecal samples examined from five control calves not fed esculin. Coumarin compounds that occur naturally in dietary plants or when supplemented in the diet probably inhibit the survival of E. coli O157 in the gut.

Epidemiological evidence suggests that dietary intake of carotenoids and tocopherols may influence the risk of certain chronic diseases, such as cancer and CVD. In vitro studies investigating the synergistic effects of mixtures of carotenoids and tocopherols have been hindered due to the difficulty of solubilising these lipophilic compounds. The objective of the present study was to develop a system for delivering tocopherols and carotenoids simultaneously to cells in culture. Differentiated human colonic adenocarcinoma cells (CaCo-2) were incubated with a mixture of these phytochemicals for 24 h. The phytochemical mixture included carotenoids (astaxanthin, canthaxanthin, lutein, lycopene, α-carotene, β-carotene) and tocopherols (α-tocopherol and γ-tocopherol). The emulsifiers polyoxyethylene sorbitan monopalmitate (Tween 40) and polyoxyethylene sorbitan monooleate (Tween 80) were employed as the delivery vehicles, and were compared with tetrahydrofuran (THF). Each vehicle was added at a maximum concentration of 1 ml/l. No toxic effects to the CaCo-2 cells were noted when Tween 40 or Tween 80 were used. Both Tween 40 and Tween 80 resulted in greater solubility of the mixture and delivered substantially more carotenoids and tocopherols to the cells than THF. In particular, lycopene was detected within the cells when Tween 40 and Tween 80 were employed, whereas it was below the limits of detection by HPLC when THF was used as the delivery vehicle. The phytochemicals were retained within the cells for 24 h after supplementation. Tween 40 and Tween 80 have potential as simple, rapid and non-toxic methods for delivering mixtures of carotenoids and tocopherols to cells in culture.

Coding diet records is a basic element of most dietary surveys, yet it often receives little attention even though errors in coding can lead to flawed study results. In the INTERnational study of MAcro- and micronutrients and blood Pressure (INTERMAP study), efforts were made to minimise errors in coding the 18 720 diet records. Staff were centrally trained and certified before being able to process study data and ongoing quality control checks were performed. This involved the senior (site) nutritionist re-coding randomly selected diet records. To facilitate standardisation of coding in the UK, a code book was designed; it included information about coding brand items, density and portion size information, and default codes to be assigned when limited information was available for food items. It was found that trainees, despite previous experience in coding elsewhere, made coding errors that resulted in errors in estimates of daily energy and nutrient intakes. As training proceeded, the number of errors decreased. Compilation of the code book was labour-intensive, as information from food manufacturers and retailers had to be collected. Strategies are required to avoid repetition of this effort by other research groups. While the methods used in INTERMAP to reduce coding errors were time consuming, the experiences suggest that such errors are important and that they can be reduced.

We previously reported that pregnant women whose plasma Zn concentrations were below the 50th percentile tended to have high pre-pregnancy BMI (kg/m2) values. We therefore hypothesized that in pregnant women, plasma Zn concentrations are negatively correlated with BMI. We evaluated the association between BMI values and plasma Zn concentrations in 1474 women whose blood samples were obtained before 15 weeks of gestation. Their mean age was 22·7 years and mean gestational age at blood sampling was 10 weeks. The mean plasma Zn concentration and BMI were 11·6 μmol/l and 26·6 kg/m2 respectively. Because plasma Zn concentrations decrease as gestational age increases, plasma Zn concentrations were standardized by Z-scores. Z-score distributions were compared among the quartiles of BMI. The highest BMI group had the lowest plasma Zn concentrations, whereas the lowest BMI group had the highest; the differences were significant between the BMI groups (P<0·0001). The interpretation of plasma Zn concentrations to assess Zn nutriture in pregnancy may be complicated not only by the well-established factor of gestational age at blood sampling, but also by a previously unrecognized factor, maternal BMI.

In order to teach suitable feeding and hygiene practices to a group of randomly selected Qashqa'i tribe families with 406 children aged 0–59 months, a culturally appropriate community-based education intervention approach was used. To assess the impact of the intervention on the study group, another group of families with 405 children were randomly selected to serve as the controls. At the beginning of the intervention programme both groups of children had access to a similar diet, consisting of cereals, beans, oil, sugar, milk and yoghurt. Baseline data, age, gender, weight, height and mean arm circumference (MAC), were obtained before the intervention. Using Hubley's behavioural change model, the components of which deal with beliefs, attitudes, subjective norms and enabling factors, the research team studied the behaviour of the family members and tried to change their nutritional behaviour. This was achieved by designing a suitable education programme to be carried out for 12 months. During the programme, families were instructed to follow different methods of food preparation and cooking practices. The final data were collected 3 months after the end of the intervention programme. The results indicated that the children in the study group gained: 1·16 (SD 1·2) kg body weight, 0·033 (SD 0·05) m in height, 0·0067 (SD 0·015) m in MAC, 0·8 (SD 1) in weight-for-age Z-score, 0·97 (SD 1·7) in height-for-age Z-score and 0·28 (SD 1·8) in weight-for-height Z-score by the end of the study. The corresponding values for the control group were 0·42 (SD 1·0), 0·0167 (SD 0·047), 0·0017 (SD 0·012), 0·35 (SD 1·1), 0·56 (SD 1·5) and 0·014 (SD 1·6) respectively and the differences were statistically significant (P<0·05). These findings suggest that educational interventions involving parents and/or other family members who might play a role in the care behaviour and care resources are important in feeding the children energy- and protein-enriched, hygienic, simple and cheap foods. Such practices could improve child growth even under conditions of poverty.

Many studies in humans volunteers have shown that dietary docosahexaenoic acid (DHA) supplied as triacylglycerol can increase DHA levels in blood lipids but often strongly decreases those of arachidonic acid (AA). The aim of the present study was to determine the effect of dietary supplementation with egg-yolk powder enriched in DHA, corresponding to the French recommended dietary allowance for DHA, on the blood lipid status of an elderly population. Institutionalised elderly individuals aged between 63 and 93 years consumed an egg product enriched in DHA (150 mg/d) once daily for 9 months. Plasma lipids and the fatty acid composition of erythrocyte membranes were determined every 3 months. The supplementation induced an increase in the PUFA content of plasma and erythrocyte membranes which was +14·5 and +25·3 %, respectively, at 9 months. This effect was mainly due to the level of DHA and, unexpectedly, to that of AA which continuously increased. This increase in AA was the result of an increased dietary intake (+50 mg/d) and very probably of an increased biosynthesis as demonstrated by the behaviour of di-homo-γ-linolenic acid. The supplementation resulted in a blood PUFA status comparable with that of young healthy controls. The data are consistent with a strong regulatory action of the dietary treatment on the subjects' lipid metabolism.