The objective of the present study was to evaluate the effect of a paediatric tube feed supplemented with a multifibre mixture on the gut microbiota and nutritional and micronutrient status of children on long-term enteral nutrition (EN). A randomised, controlled, double-blind, cross-over trial (2 × 3 months) with a washout period of 1 month was carried out. Twenty-seven children (80 % neurologically impaired) aged 11·9 (sd 3·9) years, on long-term EN (4·8 (sd 3·9) years) were recruited. The analyses of the children's faecal pH, microbiota along with anthropometric measures, bowel movements and markers of blood micronutrient status were made. Twenty children completed the study. A significant increase in the proportion of stool bifidobacteria (+16·6 %, P < 0·05) was observed during the multifibre period than during the fibre-free period, together with a significant reduction in stool pH (P < 0·001). Stool frequency and consistency as well as growth did not differ between the two periods. There was a significant increase (P < 0·05) in plasma ferritin at the end of the fibre-free period, but plasma ferritin levels remained within normal ranges during both periods. No diet effects on other blood parameters were observed. In conclusion, addition of a multifibre mixture with prebiotic components to paediatric EN is well tolerated, promotes bifidobacteria and reduces stool pH, indicating an improved gut health.

To evaluate the extent to which daily oral Fe supplements may block Fe absorption from a subsequent dose, we compared effects of oral and intraperitoneal (i.p.) Fe supplementation on Fe status in anaemic rats (haemoglobin (Hb) 90 g/l). A ligated duodenal loop technique was used to assess the effects of the Fe supplements administered either orally or i.p. at different frequencies on Fe absorption from a subsequent test dose. Anaemic Sprague–Dawley rats were assigned to seven groups of eight rats each and received either oral or i.p. Fe supplements for 3 d as follows: (1) 4 mg oral supplement daily (three doses in 3 d); (2) 4 mg oral supplement once (one dose on day 1, low-Fe dose on days 2 and 3); (3) 12mg oral supplement once (one dose on day 1, low-Fe dose on days 2 and 3); (4) 3.2 mg i.p. supplement daily (three doses in 3d); (5) 3.2 mg i.p. supplement once (one dose on day 1); (6) 9.6 mg i.p. supplement once (one dose on day 1); (7) low-Fe diet (control). The effectiveness of the supplements in treating Fe deficiency on each of the two test-factors, i.e. route of administration and frequency of dose, was assessed by determining Hb-Fe gain and liver-Fe stores after the 3 d test period. Oral supplementation was as effective as i.p. in improving the Fe status of the anaemic animals. However, a 15 min absorption of a radio-Fe test dose from a ligated loop in i.p.-supplemented groups was significantly higher (11.68 (sd 1.70) %, 17.49 (sd 4.59) %, 16.71 (sd 3.39) %) than in orally supplemented groups (3.24 (sd 1.35) %, 2.45 (sd 1.05) %, 1.80 (sd 0.35) %) despite equal body Fe stores. No significant difference in intestinal Fe absorption efficiency was detected within the oral groups but those supplemented only once were more effective than or as effective as the group receiving daily supplements for 3d in improving Fe status as indicated by Hb-regeneration efficiency. We conclude that there is a mucosal block with the administration of oral Fe supplements but the extent of this blocking effect during oral Fe supplementation is not as dramatic as currently thought in the context of the poor efficacy of daily Fe supplementation programmes.

1. Details are given of modifications to standard pH measuring equipment enabling it to be used to record continuously the pH in the bovine rumen for up to 4 weeks. The operation of the apparatus and examples of its use are presented.

Whole-body fatty acid analysis in rats has previously shown that 50–70% of dietary linoleate and α-linolenate is β-oxidized to CO2 and that this value increases with refeeding after a single episode of fasting. Our hypothesis was that repeated fasting-refeeding or weight-cycling would increase the β-oxidation of linoleate and α-linolenate thereby depleting their whole-body levels. In rats consuming 3% energy as linoleate and 0·15 % energy as α-linolenate during a 16 d balance period, 19% of the linoleate consumed accumulated in weight-cycled rats compared with 34% in the free-fed controls (P < 0.01). Similarly, 11% of the α-linolenate consumed accumulated in the weight-cycled rats compared with 22% in the controls (P < 0.01). Arachidonate and docosahexaenoate also accumulated to lower extents in the weight-cycled rats than in the controls. In contrast, whole-body accumulation of palmitate, stearate and oleate was not different between the weight-cycled group and the controls when measured as a proportion of intake or relative to weight gain. Thus, whole-body depletion of linoleate and α-linolenate did not occurper se but the partitioning of linoleate and α-linolenate was significantly altered by weight-cycling resulting in lower whole-body accumulation and higher apparent oxidation of all polyunsaturates especially linoleate and α-linolenate.

Individuals with CHD are at increased risk of poor mental well-being. Dietary intake of EPA and DHA, the main n-3 fatty acids from fish, may be beneficial to mental well-being. We examined the association of EPA+DHA and fish intake with mental well-being in 644 participants, aged 60–80 years, with a history of myocardial infarction. Habitual food intake was assessed with a 203-item FFQ. Depressive symptoms were assessed with the self-report geriatric depression scale, and dispositional optimism was assessed with the revised life orientation test (LOT-R) and a four-item questionnaire (4Q). In Cox-regression models modified for cross-sectional analyses, we adjusted for sex, age, energy intake, BMI, family history of depression, education, marital status, smoking, physical activity and intake of saturated fat, alcohol and fibre. Compared with the lower tertile, subjects in the higher tertile of EPA+DHA intake had a lower prevalence of depressive symptoms, but this association was not statistically significant (prevalence ratio (PR) 0·78; 95 % CI 0·50, 1·22, P-trend 0·27). The higher tertile of EPA+DHA intake was positively associated with dispositional optimism measured with the 4Q (PR 0·69; 95 % CI 0·46, 1·03, P-trend 0·05), but not according to the LOT-R. Fish intake was not related to either depressive symptoms or dispositional optimism. In conclusion, intake of EPA+DHA was positively associated with dispositional optimism assessed with the 4Q, but not with optimism assessed with the LOT-R or with depressive symptoms.

1. Sulphur amino acid metabolism in livers from rats which had been fed ad lib. on a restricted diet (malnourished) or a Zn-deficient diet was investigated. Perfusion of normal livers with different amounts of L-methionine revealed that homocysteine was recycled four to five times before being eliminated via the transsulphuration pathway.

2. From the perfusion experiments, we found no evidence that any of the enzymes involved in recycling homocysteine back to methionine (methylation pathway) were adversely effected by Zn deficiency or malnutrition.

3. The intracellular concentration of cystathionine and S-adenosylmethionine increased in all livers in response to increased concentrations of L-methionine (L-Met) in the perfusate.

4. The intracellular concentration of S-adenosylhomocysteine remained the same in all livers regardless of the concentration of perfusate methionine.

5. Although homocysteine did not accumulate in the cell, it was excreted into the perfusate. The amount of homocysteine in the perfusate of livers from Zn-deficient rats was higher than either ad lib. or pair-fed rats.

6. The breakdown of homocysteine, via the transsulphuration pathway, was augmented by Zn deficiency. This was apparent from the greater amount of α-ketobutyrate excreted by livers from Zn-deficient rats compared with pair-fed or ad lib.-fed controls.

7. The increase in metabolism of L-Met, via the transsulphuration pathway, in the livers from Zn-deficient rats appears to reflect the lack of demand for this compound in protein synthesis and methylation reactions (Wallwork & Duerre, 1985).

Fluctuations in Zn metabolism throughout gestation and lactation might affect Zn requirements. However, scientific data on Zn requirements for breeding sows are limited. The objective of the present study was to assess the Zn status of primiparous and multiparous sows using different Zn status biomarkers, to identify periods of critical Zn status throughout the reproductive cycle at different parities. Blood samples were taken after overnight fasting before feeding in the morning from five primiparous and ten multiparous sows at fixed time intervals during gestation (days − 5, 0 (insemination), 21, 42, 63 and 84), around parturition (days 108, 112, 115 (parturition) and 118) and during lactation (days 122, 129 and 143 (weaning)). At parturition, blood samples were collected from two randomly selected piglets per sow before colostrum intake. Plasma was analysed for Zn and Cu contents, whereas serum was analysed for alkaline phosphatase, metallothionein and albumin concentrations. Independently of parity, all biomarkers fluctuated differently during gestation and lactation (P< 0·050). This reflects their different roles in Zn metabolism, and suggests that the choice of a Zn status biomarker necessitates careful consideration. Low average plasma Zn concentration at the end of gestation and throughout lactation seem to be replenished towards weaning.

Children’s vegetable consumption is generally below national recommendations in the UK. This study examined predictors of vegetable intake by children aged 1·5–18 years using counts and portion sizes derived from 4-d UK National Diet and Nutrition Survey food diaries. Data from 6548 children were examined using linear and logit multilevel models. Specifically, we examined whether demographic variables predicted vegetable consumption, whether environmental context influenced portion sizes of vegetables consumed and which food groups predicted the presence (or absence) of vegetables at an eating occasion (EO). Larger average daily intake of vegetables (g) was predicted by age, ethnicity, equivalised income, variety of vegetables eaten and average energy intake per d (R2 0·549). At a single EO, vegetables were consumed in larger portion sizes at home, with family members and at evening mealtimes (Conditional R2 0·308). Within EO, certain configurations of food groups such as carbohydrates and protein predicted higher odds of vegetables being present (OR 12·85, 95 % CI 9·42, 17·54), whereas foods high in fats, sugars and salt predicted a lower likelihood of vegetable presence (OR 0·03, 95 % CI 0·02, 0·04). Vegetables were rarely eaten alone without other food groups. These findings demonstrate that only one portion of vegetables was eaten per d (median) and this was consumed at a single EO, therefore falling below recommendations. Future research should investigate ways to encourage vegetable intake at times when vegetables are not regularly eaten, such as for breakfast and as snacks, whilst considering which other, potentially competing, foods are presented alongside vegetables.

Several studies have investigated the effects of fish oil (FO) on infant growth, but little is known about the effects of FO and sex on insulin-like growth factor-1 (IGF-1), the main regulator of growth in childhood. We explored whether FO v. sunflower oil (SO) supplementation from 9 to 18 months of age affected IGF-1 and its binding protein-3 (IGFBP-3) and whether the potential effects were sex specific. Danish infants (n 115) were randomly allocated to 5 ml/d FO (1·2 g/d n-3 long-chain PUFA (n-3 LCPUFA)) or SO. We measured growth, IGF-1, IGFBP-3 and erythrocyte EPA, a biomarker of n-3 LCPUFA intake and status, at 9 and 18 months. Erythrocyte EPA increased strongly with FO compared with SO (P<0·001). There were no effects of FO compared with SO on IGF-1 in the total population, but a sex×group interaction (P=0·02). Baseline-adjusted IGF-1 at 18 months was 11·1 µg/l (95 % CI 0·4, 21·8; P=0·04) higher after FO compared with SO supplementation among boys only. The sex×group interaction was borderline significant in the model of IGFBP-3 (P=0·09), with lower IGFBP-3 with FO compared with SO among girls only (P=0·03). The results were supported by sex-specific dose–response associations between changes in erythrocyte EPA and changes in IGF-1 and IGFBP-3 (both P<0·03). Moreover, IGF-1 was sex specifically associated with BMI and length. In conclusion, FO compared with SO resulted in higher IGF-1 among boys and lower IGFBP-3 among girls. The potential long-term implications for growth and body composition should be investigated further.

In the UK contemporary estimates of dietary Fe intakes rely upon food Fe content data from the 1980s or before. Moreover, there has been speculation that the natural Fe content of foods has fallen over time, predominantly due to changes in agricultural practices. Therefore, we re-analysed common plant-based foods of the UK diet for their Fe content (the ‘2000s analyses’) and compared the values with the most recent published values (the ‘1980s analyses’) and the much older published values (the ‘1930s analyses’), the latter two being from different editions of the McCance and Widdowson food tables. Overall, there was remarkable consistency between analytical data for foods spanning the 70 years. There was a marginal, but significant, apparent decrease in natural food Fe content from the 1930s to 1980s/2000s. Whether this represents a true difference or is analytical error between the eras is unclear and how it could translate into differences in intake requires clarification. However, fortificant Fe levels (and fortificant Fe intake based upon linked national data) did appear to have increased between the 1980s and 2000s, and deserve further attention in light of recent potential concerns over the long-term safety and effectiveness of fortificant Fe. In conclusion, the overall Fe content of plant-based foods is largely consistent between the 1930s and 2000s, with a fall in natural dietary Fe content negated or even surpassed by a rise in fortificant Fe but for which the long-term effects are uncertain.

The Thriposha programme is a community-level nutrition intervention in Sri Lanka that provides a combination of energy, protein and micronutrients as a ‘ready-to-eat’ cereal-based food. We measured the bioavailability of Fe and Zn from Thriposha formula at two different molar ratios of Zn:Fe in order to determine the effect on Fe and Zn absorption. Children 4–7 years (n 53) were given a meal prepared with 50 g Thriposha containing 1·5 mg Zn as zinc sulphate and either 9 mg (high Fe concentration (HiFe)) or 4·5 mg (low Fe concentration (LoFe)) Fe as ferrous fumarate. Zn and Fe percent absorption were measured using stable isotopes by tracer:tracee ratio and by incorporation of erythrocytes, respectively. Percent Fe absorption from the two meals was similar (6·6 % (4·8) v. 4·8 % (2·6); P = 0·15), but total Fe absorption was significantly higher from the HiFe meal (0·59 (0·43) mg) than the LoFe meal (0·20 (0·12) mg; P = 0·01). There was no significant difference between the two groups in Zn absorption (10·7 % (0·9) v. 8·8 % (1·4), P = 0·13, respectively). Decreasing the amount of Fe in Thriposha did not cause a significant change in the percent absorption of Fe and Zn, but significantly lowered the total amount of absorbed Fe. These results demonstrate the utility of maintaining a higher Fe content in this supplement. Further studies to increase Zn content are warranted while maintaining a HiFe.

There is limited information regarding the nutrition profile and diet quality of meal plans from currently popular weight loss (WL) diets in Australia. This includes the energy content (kilojoules), the macronutrient distribution and the micronutrient composition. Further, these diets have not been compared with current government guidelines and healthy eating principles (HEP) for nutritional adequacy. Popular diets were identified through grey literature, trending searches and relative popularity in Australia. Meal plans for each diet were analysed using Foodworks Dietary Software to determine food group intake, micronutrient and macronutrient distribution. The results indicated that all popular diets assessed deviated from government recommended HEP such as the Australian Guide to Healthy Eating and the Mediterranean diet. In most cases, both popular diets and the HEP had low intakes of multiple food groups, low intakes of essential micronutrients and a distorted macronutrient distribution. Popular diets may not provide adequate nutrition to meet needs, particularly in the long term and potentially resulting in micronutrient deficiency. When energy restricting for WL, meal plans should be highly individualised in conjunction with a qualified nutrition professional to ensure adequate dietary intake.

It is unknown whether diet quality is associated with microvascular structure. The present study aimed to investigate the relationship between diet quality, reflecting adherence to dietary guidelines, with retinal microvascular calibre in older adults. The dietary data of 2720 Blue Mountains Eye Study participants, aged 50+ years, were collected using a semi-quantitative FFQ. A modified version of the Healthy Eating Index for Australians was developed to determine total diet scores (TDS). Fundus photographs were taken and retinal vascular calibre measured using computer-assisted techniques and summarised. After adjusting for age, sex, BMI, mean arterial blood pressure, smoking, serum glucose, leucocyte count and history of diagnosed stroke or CHD, persons with higher TDS had healthier retinal vessels cross-sectionally, with wider retinal arteriolar calibre (by approximately 3 μm, comparing the highest with the lowest quartile of TDS, Ptrend= 0·0001) and narrower retinal venular calibre (by approximately 2·5 μm; Ptrend= 0·02). In younger subjects aged ≤ 65 years, increasing TDS (lowest to the highest quartile) was associated with healthier retinal vessels: approximately 4·4 μm wider retinal arteriolar (Ptrend< 0·0001) and approximately 2·3 μm narrower venular calibre (Ptrend= 0·03). After multivariable adjustment, however, baseline TDS were not associated with retinal arteriolar (Ptrend= 0·89) or venular calibre (Ptrend= 0·25), 5 years later. Also, baseline TDS were not associated with the 5-year change in retinal arteriolar (β = 0·14; P= 0·29) or venular calibre (β = − 0·26; P= 0·07). Greater compliance with published dietary guidelines (higher diet quality) was cross-sectionally associated with wider retinal arterioles and narrower venules, indicating better retinal microvascular health.

Little is known about the aetiology of brain tumours. One putative factor suggested from animal models is a protective effect of dietary Zn. We tested the hypothesis that increased compared with low dietary Zn intake is protective against brain tumour development. We conducted a population-based case–control study in the UK, of adults aged 18–69 years, between 2001 and 2004 aiming to identify possible risk factors. Dietary information was collected from 637 cases diagnosed with a glioma or meningioma, and 876 controls. Data were obtained from a self-completed FFQ. Multivariate logistic regression analysis was conducted, adjusting for socio-demographic factors, season of questionnaire return, multivitamin supplementation and energy intake. Although a weak protective effect was observed for the third quartile of intake (normal compared with low intake) in the meningioma group, this was limited to the specific brain tumour subtype and quartile, and was not significant after also adjusting for intake of other elements. Overall there was no significant effect of Zn intake. No association or dose–response relationship was observed between increased compared with low Zn intake and risk of glioma or meningioma.

Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds.

Ingestion of mycoprotein stimulates skeletal muscle protein synthesis (MPS) rates to a greater extent than concentrated milk protein when matched for leucine content, potentially attributable to the wholefood nature of mycoprotein. We hypothesised that bolus ingestion of mycoprotein as part of its wholefood matrix would stimulate MPS rates to a greater extent compared with a leucine-matched bolus of protein concentrated from mycoprotein. Twenty-four healthy young (age, 21 ± 2 years; BMI, 24 ± 3 kg.m2) males received primed, continuous infusions of L-[ring-2H5]phenylalanine and completed a bout of unilateral resistance leg exercise before ingesting either 70 g mycoprotein (MYC; 31·4 g protein, 2·5 g leucine; n 12) or 38·2 g of a protein concentrate obtained from mycoprotein (PCM; 28·0 g protein, 2·5 g leucine; n 12). Blood and muscle samples (vastus lateralis) were taken pre- and (4 h) post-exercise/protein ingestion to assess postabsorptive and postprandial myofibrillar protein fractional synthetic rates (FSR) in resting and exercised muscle. Protein ingestion increased plasma essential amino acid and leucine concentrations (P < 0·0001), but more rapidly (both 60 v. 90 min; P < 0·0001) and to greater magnitudes (1367 v. 1346 μmol·l–1 and 298 v. 283 μmol·l–1, respectively; P < 0·0001) in PCM compared with MYC. Protein ingestion increased myofibrillar FSR (P < 0·0001) in both rested (MYC, Δ0·031 ± 0·007 %·h–1 and PCM, Δ0·020 ± 0·008 %·h–1) and exercised (MYC, Δ0·057 ± 0·011 %·h–1 and PCM, Δ0·058 ± 0·012 %·h–1) muscle, with no differences between conditions (P > 0·05). Mycoprotein ingestion results in equivalent postprandial stimulation of resting and post-exercise myofibrillar protein synthesis rates irrespective of whether it is consumed within or without its wholefood matrix.

This study describes a methodology with potential application in the estimation of essential fatty acid (EFA) requirements of fish larvae. Senegalese sole (Solea senegalensis) larvae were fed, from 16 days after hatching (DAH), on Artemia enriched with different oils, inducing graded dietary concentrations of DHA: (1) soyabean oil, containing no measurable amounts of DHA (NDHA); (2) fish oil, inducing a medium DHA level (MDHA, 3 g DHA/100 g fatty acids); and (3) a mixture of Easy DHA Selco and Microfeed, resulting in high DHA content (HDHA, 8 g/100 g). At 28 DAH a metabolic trial was conducted where larvae were tube fed [1-14 C]DHA, in order to determine its absorption, retention in the gut and body tissues, as well as its oxidation. At 23 DAH the HDHA treatment induced a significantly higher larval growth, while at 32 DAH significant differences were only found between the NDHA and HDHA treatments. The absorption of tube-fed [1-14 C]DHA was extremely high (94–95 %) and independent of feeding regime. However, in larvae fed NDHA Artemia, a significantly higher amount of label was retained in the gut compartment and a concurrently lower retention was measured in the body. A significantly higher proportion of the absorbed DHA label was oxidized in larvae fed HDHA, compared to NDHA. Based on these results, we suggest that increasing dietary supply of DHA above the larval requirement level results in its increased oxidation for energy purposes and we propose potential applications of the tube feeding methodology using radiolabelled EFA in conjunction with dose–response studies.

The brain development and performance of rats fed throughout two generations with an indigenous maize tortilla-based diet was studied. The experiment compared casein control with five different diets produced from: regular fresh masa; regular, enriched dry masa flour containing thiamin, riboflavin, niacin, folic acid, Fe and Zn (REDMF); dry masa flour fortified with 60g/kg defatted soyabean meal and enriched (FEDMF); enriched quality protein maize (QPM) flour (EQPM); QPM flour fortified with 30g/kg defatted soyabean meal and enriched (FEQPM). In both generations, brain and cerebellum weights and myelin concentration were significantly higher (p<0·05) in rats fed the FEDMF and FEQPM diets. There was no significant difference (p>0·05) in brain DNA in first-generation rats; however, second-generation rats fed FEDMF, EQPM and FEQPM tortillas had higher cerebral DNA, neuron size and brain activity as estimated by the RNA:DNA ratio. Short-term and long-term memory performance in the Morris maze improved (p<0·05) among rats fed the FEDMF, FEQPM and EQPM diets. Second-generation rats fed the FEDMF and FEQPM diets had a superior (p<0·05) working memory and learning performance. The utilisation of regular or QPM tortillas enriched with selected micronutrients and fortified with soyabean is highly recommended to assure adequate brain development. The high lysine–tryptophan QPM made it possible to save half of the soyabean flour without sacrificing the nutritional value of soyabean-fortified tortillas.