The n-3 PUFA are a unique class of fatty acids that cannot be manufactured by the body, and must be acquired via dietary sources. In the UK, as well as in other Western nations, these ‘essential’ fatty acids are consumed in quantities that fall below government guidelines. The present study explored the effects of 12 weeks' dietary supplementation with 1 g/d of two types of fish oil (FO; DHA-rich and EPA-rich) in 159 healthy young adults aged 18–35 years. An assessment of performance on a battery of computerised cognitive tasks and mood measures took place before and following the 12-week treatment regimen. Venous blood samples were also supplied by participants at both time points which were later analysed for serum fatty acid concentrations. Despite good adherence to the study protocol – as reflected in increased concentrations of n-3 serum fatty acids – compared with placebo, the observed effects of both active treatments were minimal. The only finding of note revealed that supplementation with EPA-rich FO may reduce subjective mental fatigue at times of high cognitive demand, although further investigation is required. These findings, taken together with other recent reports of null effects, suggest that dietary supplementation with n-3 PUFA in healthy, normally developing and impairment-free populations is unlikely to result in cognitive enhancement.

Patients treated with haemodialysis are at high risk of sudden cardiac death (SCD) often caused by arrhythmias. Atrial fibrillation (AF) is frequent among haemodialysis patients and is associated with increased mortality. Prolonged QTc is a risk marker of ventricular arrhythmia and is thereby associated with SCD. Studies have suggested that n-3 PUFA may have an antiarrhythmic effect, but the exact mechanism is not clear. The aim of this study was to examine whether AF was associated with n-3 PUFA in plasma phospholipids and whether supplementation with n-3 PUFA would shorten the QTc interval in haemodialysis patients compared to placebo. In a double-blinded randomised, placebo-controlled intervention trial 206 haemodialysis patients with CVD were treated with 1·7 g n-3 PUFA or placebo (olive oil) daily for 3 months. Blood samples and electrocardiogram evaluations were carried out at baseline and after 3 months. The QT interval, PQ interval and heart rate were measured in all patients with sinus rhythm (SR). At baseline 13 % of patients had AF. The content of the n-3 PUFA, DHA, was significantly lower (P < 0·05) in serum of patients with AF compared with patients with SR. Thus, the DHA content was independently negatively associated with AF. Supplementation with n-3 PUFA did not shorten the QT interval significantly compared to the placebo group (P = 0·42), although subgroup analysis within the n-3 PUFA group revealed a shortening effects on QTc (P = 0·01). In conclusion, an inverse association was found between the presence of AF and the plasma DHA in haemodialysis patients. Intervention with n-3 PUFA did not shorten the QTc interval compared to placebo.

Increased gluconeogenesis (GNG) has been suggested to contribute to protein-induced satiety via modulation of glucose homoeostasis. The objective was to determine GNG and appetite in healthy human subjects after a high-protein v. a normal-protein diet and to assess whether GNG contributes to protein-induced satiety. A total of twenty-two healthy subjects (ten men and twelve women: age 23 (sem 1) years, BMI 22·1 (sem 0·5) kg/m2) received an isoenergetic high-protein (30/0/70 % of energy from protein/carbohydrate/fat) or normal-protein diet (12/55/33 % of energy from protein/carbohydrate/fat) for 1·5 d in a randomised cross-over design. Appetite ratings were measured using visual analogue scales (VAS); endogenous glucose production and GNG were measured via infusion of [6,6-2H2]glucose and ingestion of 2H2O. Moreover, fasting glucose and β-hydroxybutyrate concentrations were measured. Glycogen stores were lowered at the start with a glycogen-lowering exercise test. During the high-protein compared with the normal-protein diet, GNG was increased and appetite was suppressed (GNG: 148 (sem 7) v. 133 (sem 6) g/24 h, P < 0·05; and 24 h area under the curve for hunger: 694 (sem 46) v. 1055 (sem 52) mm VAS × 24 h, P < 0·001; fullness: 806 (sem 59) v. 668 (sem 64) mm VAS × 24 h, P < 0·05; desire to eat: 762 (sem 48) v. 1004 (sem 66) mm VAS × 24 h, P < 0·001). There was no correlation between appetite ratings and GNG. Glucose concentration was lower (4·09 (sem 0·10) v. 4·89 (sem 0·06) mmol/l, P < 0·001) and β-hydroxybutyrate concentration was higher (1349 (sem 139) v. 234 (sem 25) μmol/l, P < 0·001) after the high-protein compared with the normal-protein diet. In conclusion, after a high-protein diet, GNG was increased and appetite was lower compared with a normal-protein diet; however, these were unrelated to each other. An increased concentration of β-hydroxybutyrate may have contributed to appetite suppression on the high-protein diet.

High concentrations of fluoride (F) in powdered milk (formula milk) can have adverse health effects on the body. The F concentration in powdered milk was analysed in Iran in 2010. A total of twelve commercial brands of highly consumed powdered milk were selected to analyse the F content through the standard F ion-selective electrode method. From each brand, three samples with different production dates were selected. The means and standard deviation for F concentration in all the samples was 1·73 (sd 0·3) μg F/g. The minimum and maximum F content in powdered milk brands Humana2 and Humana3 was 1·32 (sd 0·1) and 2·36 (sd 0·3) μg F/g, respectively. The study revealed that there was no significant difference in F concentration in the samples that belonged to various dates. Humana3 had a high F concentration (with an average of 2·36 (sd 0·3) μg F/g), which can be a risk factor for increased dental fluorosis, especially when being prepared using water with a high content of F.

Poor vitamin D status is common in older people and results in osteoporosis; osteomalacia is associated with a wide range of non-communicable diseases and has potential effects on poor health outcomes. Pain is also common in older people and can be substantially disabling. The aim of the present analysis is to investigate associations between serum 25-hydroxy vitamin D (25(OH)D) and self-reported current symptoms of pain in a cross-sectional, nationally representative sample of 2070 adults aged ≥ 65 years living in the community in England in 2005. Measurements included serum 25(OH)D, pain status and covariates, namely, age, sex, social class, season of examination, use of vitamin supplements and physical health status. Results show that the symptoms of moderate/extreme pain (present in 53 % of the sample) were associated with poor vitamin D status, independent of other covariates. Particular advantages of the present study were the presence of directly measured vitamin D levels and a large and nationally representative sample. Poor vitamin D status is common and an associated risk factor for pain in older people living in northern latitudes. The direction of causation cannot be inferred from a cross-sectional study and further prospective research is required to clarify this. Regardless of the direction of causation, the relationship is potentially of high public health importance because of the adverse impact of both states on well-being. It is important that older people in pain are screened for vitamin D status and provided with appropriate interventions.

There is a growing interest in modulating gut microbiota with diet in the context of obesity. The purpose of the present study was to evaluate the dose-dependent effects of prebiotics (inulin and oligofructose) on gut satiety hormones, energy expenditure, gastric emptying and gut microbiota. Male lean and obese JCR:LA-cp rats were randomised to either of the following: lean 0 % fibre (LC), lean 10 % fibre (LF), lean 20 % fibre (LHF), obese 0 % fibre (OC), obese 10 % fibre (OF) or obese 20 % fibre (OHF). Body composition, gastric emptying, energy expenditure, plasma satiety hormone concentrations and gut microbiota (using quantitative PCR) were measured. Caecal proglucagon and peptide YY mRNA levels were up-regulated 2-fold in the LF, OF and OHF groups and 3-fold in the LHF group. Ghrelin O-acyltransferase mRNA levels were higher in obese v. lean rats and decreased in the OHF group. Plasma ghrelin response was attenuated in the LHF group. Microbial species measured in the Bacteroidetes division decreased, whereas those in the Firmicutes increased in obese v. lean rats and improved with prebiotic intake. Bifidobacterium and Lactobacillus increased in the OHF v. OC group. Bacteroides and total bacteria negatively correlated with percentage of body fat and body weight. Enterobacteriaceae increased in conjunction with glucose area under the curve (AUC) and glucagon-like peptide-1 AUC. Bacteroides and total bacteria correlated positively with ghrelin AUC yet negatively with insulin AUC and energy intake (P < 0·05). Several of the mechanisms through which prebiotics act (food intake, satiety hormones and alterations in gut microbiota) are regulated in a dose-dependent manner. The combined effects of prebiotics may have therapeutic potential for obesity.

Introduction: Cardiovascular disease remains the commonest health problem in developed countries, and residual risk after implementing all current therapies is still high. The use of marine omega-3 fatty acids (DHA and EPA) has been recommended to reduce cardiovascular risk by multiple mechanisms. Objectives: To update the current evidence on the influence of omega-3 on the rate of cardiovascular events. Review Methods: We used the MEDLINE and EMBASE databases to identify clinical trials and randomized controlled trials of omega-3 fatty acids (with quantified quantities) either in capsules or in dietary intake, compared to placebo or usual diet, equal to or longer than 6 months, and written in English. The primary outcome was a cardiovascular event of any kind and secondary outcomes were all-cause mortality, cardiac death and coronary events. We used RevMan 5·1 (Mantel-Haenszel method). Heterogeneity was assessed by the I2 and Chi2 tests. We included 21 of the 452 pre-selected studies. Results: We found an overall decrease of risk of suffering a cardiovascular event of any kind of 10 % (OR 0·90; [0·85–0·96], p = 0·001), a 9 % decrease of risk of cardiac death (OR 0·91; [0·83–0·99]; p = 0·03), a decrease of coronary events (fatal and non-fatal) of 18 % (OR 0·82; [0·75–0·90]; p < 1 × 10− 4), and a trend to lower total mortality (5 % reduction of risk; OR 0·95; [0·89–1·02]; p = 0·15. Most of the studies analyzed included persons with high cardiovascular risk. Conclusions: marine omega-3 fatty acids are effective in preventing cardiovascular events, cardiac death and coronary events, especially in persons with high cardiovascular risk.

Green tea catechin has been proposed to have an anti-obesity effect. The aim of the present study was to investigate whether the effect of catechin-rich green tea in combination with inulin affects body weight and fat mass in obese and overweight adults. A total of thirty subjects were divided into a control group and an experimental group who received 650 ml tea or catechin-rich green tea plus inulin. A reduction of body weight ( − 1·29 (sem 0·35) kg) and fat mass (0·82 (sem 0·27) kg) in the experimental group was found after 6 weeks, and no adverse effects were observed. After refraining from consumption for 2 weeks, sustained effects on body weight and fat mass were observed. We conclude that continuous intake of catechin-rich green tea in combination with inulin for at least 3 weeks may be beneficial for weight management.

A rising prevalence of CVD and diabetes has been observed in sub-Saharan Africa, particularly in cities. The aim of the present study conducted in Benin was to examine the mediating role of nutrition transition in the relationship of urbanisation level and socio-economic status (SES) to cardiometabolic risk markers. A total of 541 subjects in apparent good health were randomly selected from the main city of Cotonou, a small town and its surrounding rural areas. SES was assessed based on a proxy for income and on education. Dietary intake and physical activity were assessed with at least two non-consecutive 24 h recalls. Scores for micronutrient adequacy and preventive diet were used as indicators of diet quality. Cardiometabolic risk markers were BMI, waist circumference (WC), blood pressure, serum cholesterol and insulin resistance according to homeostasis model assessment. A more advanced stage of nutrition transition, which correlated with lower diet quality scores and less physical activity, was observed in the large city compared with less urbanised locations. More obesity and more adverse cholesterol profiles, but also lower blood pressure, were present in the large city. Urbanisation, income, sedentary lifestyle and alcohol consumption, but not diet quality, independently contributed to higher BMI and WC. Higher micronutrient adequacy was independently associated with a better cholesterol profile. The study confirmed the positive rural–urban gradient in nutrition transition and cardiometabolic risk, except for blood pressure. This risk could be mitigated by a more adequate diet, particularly micronutrient intake, and a more active lifestyle.

Whether there are differences between countries in the validity of self-reported diet in relation to BMI, as evaluated using recovery biomarkers, is not well understood. We aimed to evaluate BMI-related reporting errors on 24 h dietary recalls (24-HDR) and on dietary questionnaires (DQ) using biomarkers for protein and K intake and whether the BMI effect differs between six European countries. Between 1995 and 1999, 1086 men and women participating in the European Prospective Investigation into Cancer and Nutrition completed a single 24-HDR, a DQ and one 24 h urine collection. In regression analysis, controlling for age, sex, education and country, each unit (1 kg/m2) increase in BMI predicted an approximately 1·7 and 1·3 % increase in protein under-reporting on 24-HDR and DQ, respectively (both P < 0·0001). Exclusion of individuals who probably misreported energy intake attenuated BMI-related bias on both instruments. The BMI effect on protein under-reporting did not differ for men and women and neither between countries on both instruments as tested by interaction (all P>0·15). In women, but not in men, the DQ yielded higher mean intakes of protein that were closer to the biomarker-based measurements across BMI groups when compared with 24-HDR. Results for K were similar to those of protein, although BMI-related under-reporting of K was of a smaller magnitude, suggesting differential misreporting of foods. Under-reporting of protein and K appears to be predicted by BMI, but this effect may be driven by ‘low-energy reporters’. The BMI effect on under-reporting seems to be the same across countries.

An adequate vitamin D status is essential during childhood and adolescence, for its important role in cell growth, skeletal structure and development. It also reduces the risk of conditions such as CVD, osteoporosis, diabetes mellitus, infections and autoimmune disease. As comparable data on the European level are lacking, assessment of vitamin D concentrations was included in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Fasting blood samples were obtained from a subsample of 1006 adolescents (470 males; 46·8 %) with an age range of 12·5–17·5 years, selected in the ten HELENA cities in the nine European countries participating in this cross-sectional study, and analysed for 25-hydroxycholecalciferol (25(OH)D) by ELISA using EDTA plasma. As specific reference values for adolescents are missing, percentile distribution were computed by age and sex. Median 25(OH)D levels for the whole population were 57·1 nmol/l (5th percentile 24·3 nmol/l, 95th percentile 99·05 nmol/l). Vitamin D status was classified into four groups according to international guidelines (sufficiency/optimal levels ≥ 75 nmol/l; insufficiency 50–75 nmol/l; deficiency 27·5–49·99 nmol/l and severe deficiency < 27·5 nmol/l). About 80 % of the sample had suboptimal levels (39 % had insufficient, 27 % deficient and 15 % severely deficient levels). Vitamin D concentrations increased with age (P < 0·01) and tended to decrease according to BMI. Geographical differences were also identified. Our study results indicate that vitamin D deficiency is a highly prevalent condition in European adolescents and should be a matter of concern for public health authorities.

The relationship between omega-3 polyunsaturated fatty acids (n-3 PUFA) from seafood sources (eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) or plant sources (alpha-linolenic acid, ALA) and risk of type 2 diabetes mellitus (DM) remains unclear. We systematically searched multiple literature databases through June 2011 to identify prospective studies examining relations of dietary n-3 PUFA, dietary fish and/or seafood, and circulating n-3 PUFA biomarkers with incidence of DM. Data were independently extracted in duplicate by 2 investigators, including multivariate-adjusted relative risk (RR) estimates and corresponding 95 % CI. Generalized least-squares trend estimation was used to assess dose–response relationships, with pooled summary estimates calculated by both fixed-effect and random-effect models. From 288 identified abstracts, 16 studies met inclusion criteria, including 18 separate cohorts comprising 540 184 individuals and 25 670 cases of incident DM. Consumption of fish and/or seafood was not significantly associated with DM (n = 13 studies; RR per 100 g/d = 1·12, 95 % CI = 0·94, 1·34); nor were consumption of EPA+DHA (n = 16 cohorts; RR per 250 mg/d = 1·04, 95 % CI = 0·97, 1·10) nor circulating levels of EPA+DHA biomarkers (n = 5 cohorts; RR per 3 % of total fatty acids = 0·94, 95 % CI = 0·75, 1·17). Both dietary ALA (n = 7 studies; RR per 0·5 g/d = 0·93, 95 % CI = 0·83, 1·04) and circulating ALA biomarker levels (n = 6 studies; RR per 0·1 % of total fatty acid = 0·90, 95 % CI = 0·80, 1·00, P = 0·06) were associated with non-significant trend towards lower risk of DM. Substantial heterogeneity (I2~80 %) was observed among studies of fish/seafood or EPA+DHA and DM; moderate heterogeneity ( < 55 %) was seen for dietary and biomarker ALA and DM. In unadjusted meta-regressions, study location (Asia vs. North America/Europe), mean BMI, and duration of follow-up each modified the association between fish/seafood and EPA+DHA consumption and DM risk (P-interaction ≤ 0·02 each). We had limited statistical power to determine the independent effect of these sources of heterogeneity due to their high collinearity. The overall pooled findings do not support either major harms or benefits of fish/seafood or EPA+DHA on development of DM, and suggest that ALA may be associated with modestly lower risk. Reasons for potential heterogeneity of effects, which could include true biologic heterogeneity, publication bias, or chance, deserve further investigation.