Methionine, an essential sulphur-containing amino acid (SAA), plays an integral role in many metabolic processes. Evidence for the methionine requirements of adult dogs is limited, and we employed the indicator amino acid oxidation (IAAO) method to estimate dietary methionine requirements in Labrador retrievers (n 21). Using semi-purified diets, the mean requirement was 0·55 (95 % CI 0·41, 0·71) g/4184 kJ. In a subsequent parallel design study, three groups of adult Labrador retrievers (n 52) were fed semi-purified diets with 0·55 g/4184 kJ (test diet 1), 0·71 g/4184 kJ (test diet 2) or 1·37 g/4184 kJ (control diet) of methionine for 32 weeks to assess the long-term consequences of feeding. The total SAA content (2·68 g/4184 kJ) was maintained through dietary supplementation of cystine. Plasma methionine did not decrease in test group and increased significantly on test diet 1 in weeks 8 and 16 compared with control. Reducing dietary methionine did not have a significant effect on whole blood, plasma or urinary taurine or plasma N-terminal pro B-type natriuretic peptide. Significant effects in both test diets were observed for cholesterol, betaine and dimethylglycine. In conclusion, feeding methionine at the IAAO-estimated mean was sufficient to maintain plasma methionine over 32 weeks when total SAA was maintained. However, choline oxidation may have increased to support plasma methionine and have additional consequences for lipid metabolism. While the IAAO can be employed to assess essential amino acid requirements, such as methionine in the dog using semi-purified diets, further work is required to establish safe levels for commercial diet formats.

Taurine (TAU) plays important roles in the metabolism of bile acids, cholesterol and lipids. However, little relevant information has been available in fish where TAU has been identified as a conditionally essential nutrient. The present study aimed to investigate the effects of dietary TAU on the metabolism of bile acids, cholesterol and lipids in tiger puffer, which is both an important aquaculture species and a good research model, having a unique lipid storage pattern. An 8-week feeding trial was conducted in a flow-through seawater system. Three experimental diets differed only in TAU level, that is, 1·7, 8·2 and 14·0 mg/kg. TAU supplementation increased the total bile acid content in liver but decreased the content in serum. TAU supplementation also increased the contents of total cholesterol and HDL-cholesterol in both liver and serum. The hepatic bile acid profile mainly includes taurocholic acid (94·48 %), taurochenodeoxycholic acid (4·17 %) and taurodeoxycholic acid (1·35 %), and the contents of all these conjugated bile acids were increased by dietary TAU. The hepatic lipidomics analysis showed that TAU tended to decrease the abundance of individual phospholipids and increase those of some individual TAG and ceramides. The hepatic mRNA expression study showed that TAU stimulated the biosynthesis of both bile acids and cholesterol, possibly via regulation of farnesoid X receptor and HDL metabolism. TAU also stimulated the hepatic expression of lipogenic genes. In conclusion, dietary TAU stimulated the hepatic biosynthesis of both bile acids and cholesterol and tended to regulate lipid metabolism in multiple ways.

The effect on cognitive test scores of generating differences in postprandial glycaemia using test foods or beverages has been inconsistent. Methodological issues may account for some of the variable results requiring further investigation using strong study designs into the relationship between glycaemia and cognitive functioning. The objective of this study was to determine the effects of postprandial glycaemia on cognitive function by examining cognition after consumption of foods that differ only by the rate of digestion of available carbohydrate in a population of young adults. In a double-blind, randomised, crossover trial, sixty-five participants received trifle sweetened either with a higher-glycaemic index (GI) sugar (sucrose; GI 65) or a lower-GI sugar (isomaltulose; GI 34). Cognitive tests were completed prior to trifle consumption, and 60 and 120 min after. There was no between-trifle difference at 60 min in performance on free word recall (0·0 (95 % CI –0·6, 0·5)), short delay word recall (0·0 (95 % CI –0·5, 0·5)), long delay word recall (0·0 (95 % CI –0·6, 0·6)), letter–number sequence recall (0·3 (95 % CI − 0·2, 0·7)) and visuo-spatial recall (–0·2 (95 % CI –0·6, 0·2)) tests. At 120 min, no difference was detected in any of these tests. The participants performed 7·7 (95 % CI 0·5,14·9) s faster in Reitan’s trail-making test B 60 min after the higher-GI trifle than the lower-GI trifle (P = 0·037). Our findings of a null effect on memory are generally consistent with other works in which blinding and robust control for confounding have been used.

Vegetable lipid emulsions (LE) contain non-declared phytosterols (PS). We aimed to determine PS content depending on the brand and LE batch, and in adult hospitalised patients treated with parenteral nutrition (PN), to establish the association between plasma and administered PS. Part I was the LE study: totals and fractions of PS in three to four non-consecutive batches from six LE were analysed. Part II was the patient study: patients with at least 7 previous days of PN with 0·8 g/kg per d of an olive/soyabean (O/S) LE were randomised (day 0) 1:1 to O/S or 100 % fish oil (FO) at a dose of 0·4 g/kg per d for 7 d (day 7). Plasma PS, its fractions, total cholesterol on days 0 and 7, their clearance and their association with PS administered by LE were studied. In part I, LE study: differences were found in the total PS, their fractions and cholesterol among different LE brands and batches. Exclusive soyabean LE had the highest content of PS (422·36 (sd 130·46) μg/ml). In part II, patient study: nineteen patients were included. In the O/S group, PS levels were maintained (1·11 (sd 6·98) μg/ml) from day 0 to 7, while in the FO group, significant decreases were seen in total PS (−6·21 (sd 4·73) μg/ml) and their fractions, except for campesterol and stigmasterol. Plasma PS on day 7 were significantly associated with PS administered (R2 0·443). PS content in different LE brands had great variability. PS administered during PN resulted in accumulation and could be prevented with the exclusive administration of FO LE.

The purpose of the present study was: (1) to develop a new dual-energy X-ray absorptiometry (DXA)-derived body volume (BV) equation with the GE-Lunar prodigy while utilising underwater weighing (UWW) as a criterion and (2) to cross-validate the novel DXA-derived BV equation (4C-DXANickerson), Wilson DXA-derived BV equation (4C-DXAWilson) and air displacement plethysmography (ADP)-derived BV (4C-ADP) in Hispanic adults. A total of 191 Hispanic adults (18–45 years) participated in the present study. The development sample consisted of 120 females and males (50 % females), whereas the cross-validation sample comprised of forty-one females and thirty males (n 71). Criterion body fat percentage (BF %) and fat-free mass (FFM) were determined using a four-compartment (4C) model with UWW as a criterion for BV (4C-UWW). 4C-DXANickerson, 4C-DXAWilson and 4C-ADP were compared against 4C-UWW in the cross-validation sample. 4C-DXANickerson, 4C-DXAWilson and 4C-ADP all produced similar validity statistics when compared with 4C-UWW in Hispanic males (all P > 0·05). 4C-DXANickerson also yielded similar BF % and FFM values as 4C-UWW when evaluating the mean differences (constant error (CE)) in Hispanic females (CE = –0·79 % and 0·38 kg; P = 0·060 and 0·174, respectively). However, 4C-DXAWilson produced significantly different BF % and FFM values (CE = 3·22 % and –2·20 kg, respectively; both P < 0·001). Additionally, 4C-DXAWilson yielded significant proportional bias when estimating BF % (P < 0·001), whereas 4C-ADP produced significant proportional bias for BF % and FFM (both P < 0·05) when evaluated in Hispanic females. The present study findings demonstrate that 4C-DXANickerson is a valid measure of BV in Hispanics and is recommended for use in clinics, where DXA is the main body composition assessment technique.

The only generally accepted treatment of coeliac disease (CD) is a lifelong gluten-free diet. Wheat gluten proteins include gliadins, low and high molecular weight glutenins. However, we have found significant structural variations within these protein families among different cultivars. To determine which structural motifs might be less toxic than others, we assessed five variants of α-gliadin immunodominant CD-toxic peptides synthesised as 16mers in CD T cell stimulation assays with gluten-sensitive T cell lines generated from duodenal biopsies from CD-affected individuals. The peptides harboured the overlapping T cell epitopes DQ 2.5-glia-α-2 and naturally occurring variants that differed in certain amino acids (AA). The results revealed that introduction of two selected AA substitutions in α-gliadin peptides reduced immunogenicity. A peptide with three AA substitutions involving two glutamic acids (E) and one glutamine residue (G) revealed the peptide was negative in 5:5 samples. We used CD small-intestinal organ culture to assess CD toxicity that revealed two peptides with selected substitution of both glutamic acid (E) and proline (P) residues abrogated evidence of CD toxicity.

Retirement is a major life transition affecting health and health behaviour, but evidence on how this transition contributes to changes in healthy food habits is scarce. We examined whether the consumption of fruit and vegetables as well as fish changes after transition into statutory retirement. The data were derived from the prospective Helsinki Health Study. At phase 1 in 2000–2002, all participants were 40- to 60-year-old employees of the City of Helsinki, Finland (n 8960, response rate 67 %). Follow-up surveys were conducted in 2007, 2012 and 2017 (response rates 79–83 %). Using the four phases, we formed three nested cohorts in which the participants either continued working or moved to statutory retirement. The final analytical sample consisted of 6887 participants (14 357 observations). Frequency of fruit, vegetable and fish consumption was calculated from a twenty-two-item FFQ. Analyses of repeated measures of food consumption before and after retirement transition were conducted with a negative binomial mixed model, adjusting for age, marital status, limiting long-standing illness and household income. During the follow-up, altogether 3526 participants retired. Transition to retirement was associated with a decrease in vegetable consumption among women and, contrarily, with an increase in fruit consumption among men (P < 0·05 for interaction between time and employment status). Fish consumption did not differ by the change in employment status. Statutory retirement can have mixed effects on healthy food habits, and these can differ between food groups and sex. Healthy food habits should be promoted among employees transitioning to retirement.

Little is known about who would benefit from Internet-based personalised nutrition (PN) interventions. This study aimed to evaluate the characteristics of participants who achieved greatest improvements (i.e. benefit) in diet, adiposity and biomarkers following an Internet-based PN intervention. Adults (n 1607) from seven European countries were recruited into a 6-month, randomised controlled trial (Food4Me) and randomised to receive conventional dietary advice (control) or PN advice. Information on dietary intake, adiposity, physical activity (PA), blood biomarkers and participant characteristics was collected at baseline and month 6. Benefit from the intervention was defined as ≥5 % change in the primary outcome (Healthy Eating Index) and secondary outcomes (waist circumference and BMI, PA, sedentary time and plasma concentrations of cholesterol, carotenoids and omega-3 index) at month 6. For our primary outcome, benefit from the intervention was greater in older participants, women and participants with lower HEI scores at baseline. Benefit was greater for individuals reporting greater self-efficacy for ‘sticking to healthful foods’ and who ‘felt weird if [they] didn’t eat healthily’. Participants benefited more if they reported wanting to improve their health and well-being. The characteristics of individuals benefiting did not differ by other demographic, health-related, anthropometric or genotypic characteristics. Findings were similar for secondary outcomes. These findings have implications for the design of more effective future PN intervention studies and for tailored nutritional advice in public health and clinical settings.

Starting university is an important time with respect to dietary changes. This study reports a novel approach to assessing student diet by utilising student-level food transaction data to explore dietary patterns. First-year students living in catered accommodation at the University of Leeds (UK) received pre-credited food cards for use in university catering facilities. Food card transaction data were obtained for semester 1, 2016 and linked with student age and sex. k-Means cluster analysis was applied to the transaction data to identify clusters of food purchasing behaviours. Differences in demographic and behavioural characteristics across clusters were examined using χ2 tests. The semester was divided into three time periods to explore longitudinal changes in purchasing patterns. Seven dietary clusters were identified: ‘Vegetarian’, ‘Omnivores’, ‘Dieters’, ‘Dish of the Day’, ‘Grab-and-Go’, ‘Carb Lovers’ and ‘Snackers’. There were statistically significant differences in sex (P < 0·001), with women dominating the Vegetarian and Dieters, age (P = 0·003), with over 20s representing a high proportion of the Omnivores and time of day of transactions (P < 0·001), with Dieters and Snackers purchasing least at breakfast. Many students (n 474, 60·4 %) changed dietary cluster across the semester. This study demonstrates that transactional data present a feasible method for dietary assessment, collecting detailed dietary information over time and at scale, while eliminating participant burden and possible bias from self-selection, observation and attrition. It revealed that student diets are complex and that simplistic measures of diet, focusing on narrow food groups in isolation, are unlikely to adequately capture dietary behaviours.

Household food insecurity (HFI) is a major concern in South Asia. The pathways by which HFI may reduce child growth remain inadequately understood. In a cohort study of 12 693 maternal–infant dyads in rural Bangladesh, we examined association and likely explanatory pathways linking HFI, assessed using a validated nine-item perception-based index, to infant size at 6 months. Mothers were assessed early in pregnancy for anthropometric status, dietary diversity and socio-economic status. Infants were assessed for weight, length, and arm, chest and head circumferences and breast and complementary feeding status at birth and 6 months of age. Extent of HFI shared a negative, dose–response association with all measures of infant size at 6 months and odds of wasting and stunting; 57–89 % of variances in the unadjusted models were explained by prenatal factors (maternal nutritional status and dietary diversity), and birth size adjusted for gestational age. Postnatal infant breast and complementary feeding and morbidity exposures explained the remaining fraction of the significant association between HFI and differences in infant arm and chest circumferences and odds of underweight. Contextual (i.e. socio-economic) factors finally brought remaining non-significant fractions of the food insecurity-related mid-infancy growth deficit to practically zero. Improving food security prior to pregnancy and during gestation would likely improve infant growth the most in rural Bangladesh.

Estimates of the components of nutrient intake variation are needed for modelling distributions of usual intake or predicting the usual intake of individuals. Season is a potential source of variation in nutrient intakes in addition to within- and between-person variation, particularly in low- or middle-income countries. We aimed to describe seasonal variation in nutrient intakes and estimate within-person, between-person and other major components of intake variance among Zambian children. Children from rural villages and peri-urban towns in Mkushi District, Zambia aged 4–8 years were enrolled in the non-intervened arm of a randomised controlled trial of pro-vitamin A carotenoid biofortified maize (n 200). Up to seven 24-h dietary recalls per child were obtained at monthly intervals over a 6-month period covering the late post-harvest (August–October), early lean (November–January) and late lean (February–April) seasons (2012–2013). Nutrient intakes varied significantly by season. For energy and most nutrients, intakes were highest in the early lean season and lower in the late post-harvest and late lean seasons. Season and recall on a market day had the strongest effects on nutrient intakes among covariates examined. Unadjusted within- to between-person variance ratios ranged from 4·5 to 31·3. In components of variance models, season accounted for 3–20 % of nutrient intake variance. Particularly in rural settings in low- and middle-income countries, where availability of locally grown, nutrient-rich foods may vary seasonally, studies should include replicates across seasons to more precisely estimate long-term usual intakes.

Laparoscopic Roux-en-Y gastric bypass (RYGB) is considered the ‘gold standard’ for surgical treatment of morbid obesity. It is hypothesised that reducing the length of the common limb positively affects the magnitude and preservation of weight loss but may also impose a risk of malnutrition. The aim of this study was to compare patients’ nutrient and vitamin deficiencies in standard RYGB with a very long Roux limb RYGB (VLRL-RYGB). This study was part of the multicentre randomised controlled trial (Dutch Common Channel Trial), including 444 patients undergoing an RYGB or a VLRL-RYGB. Laboratory results, use of multivitamin supplements and reoperations were collected at baseline and 1 year postoperative. Primary outcome measure was nutrient deficiency after 1 year postoperative. Secondary outcome measure was the reoperation rate due to malabsorption. In total, 227 patients underwent RYGB and 196 patients underwent VLRL-RYGB. Most common deficiencies at 1 year postoperative were ferritin (17·2–18·2 %), Fe (23·4–35·6 %), K (7·4–15·2 %), vitamin B12 (9·0–9·9 %) and vitamin D (22·7–34·5 %). Patients undergoing VLRL-RYGB had slightly but significantly lower levels of Ca, Fe and vitamin D compared with those undergoing RYGB at 1 year postoperative, but significantly higher levels of folic acid and Na. Reoperation rates due to malabsorption were not significantly different between RYGB (2/227, 0·9 %) and VLRL-RYGB (7/196, 3·6 %) (P = 0·088). We concluded that patients undergoing VLRL-RYGB had significantly lower levels of Ca, Fe and vitamin D compared with those undergoing RYGB at 1 year postoperative, but higher levels of folic acid and Na. Reoperation rates did not differ. Close monitoring on nutrient deficiencies should be performed in patients undergoing VLRL-RYGB.