Obesity has reached epidemic proportions and is recognised as a significant global health problem. Increased food intake and decreased physical activity are traditionally to blame for the development of obesity; however, many variables such as behaviour, diet, environment, social structures and genetics also contribute to this multifactorial disease. Complex interactions among these variables (for example, gene–environment, gene–diet and gene–gene) contribute not only to individual differences in the development of obesity, but also in treatment response. Mouse models have historically played valuable roles in understanding the genetics of traits related to energy balance and obesity. In the present review, we survey past use and examine new advances in mouse models designed to uncover the genetic architecture of obesity and its component traits. We discuss traditional models such as inbred strains and selectively bred lines and their contributions and shortcomings. We consider the evolution of mouse models into more informative resources such as outbred crosses and the Hybrid Mouse Diversity Panel, as well as novel next-generation approaches such as the Collaborative Cross. Moreover, the genetic architecture of voluntary exercise and the interactive relationship between host genetics and the gut microbiome are presented as novel phenotypes that augment studies using body weight and body fat percentage as endpoints. Understanding the intricate network of phenotypic, genotypic and environmental variables that predispose individuals to obesity will elucidate biological networks involved in the development of obesity. Knowledge obtained from advances in mouse models will inform human health and provide insight into inter-individual variability in the aetiology of obesity-related diseases.

Based on their proposed metabolic effects, we examined whether fish oil (FO) and SCFA, alone or in combination, accelerate weight loss and the resultant metabolic improvements. Obesity was induced in male C57BL/6J mice by high-energy feeding for 10 weeks. The mice were transferred to a low-fat diet (2·5w%) for 4 weeks, the source of fat being either FO, a lard–safflower oil mix (control), or both types combined with SCFA. Weight, fasting insulin, tissue and serum lipid concentrations, as well as mRNA amount of genes related to adipose inflammation and hepatic fat oxidation were determined. All groups lost weight and showed reduced fasting insulin concentrations and reduced liver TAG. However, weight loss on the control-fat diet caused significant increase in hepatic and cardiac NEFA. Substituting 20 % of the fat with SCFA increased weight loss by 48 % and reduced fasting insulin 1·5-fold more than the no-SCFA diets. It furthermore significantly increased the amount of mRNA for PPAR-α, and decreased the mRNA amount for NF-κB in the liver and white adipose tissue. The FO diets enhanced improvement of tissue lipid levels. Thus, FO improved liver TAG and NEFA levels compared with weight loss on the control diet. Combining FO and SCFA further reduced tissue NEFA accumulation. In conclusion, we found that dietary SCFA had a significant impact on gene expression in the liver and adipose tissue, and that the effect of FO on tissue NEFA content was modified by SCFA. Thus, interactions between fatty acids should be considered when studying the effects of specific fatty acids.

In the present study, we evaluated the relationship between nutritional status, disease stage and quality of life (QoL) in 100 patients recently diagnosed with gastric carcinoma. The patients' nutritional status was investigated with anthropometric, biochemical, inflammatory and functional variables; and we also evaluated the nutritional risk with the Nutritional Risk Screening 2002. Oncological staging was standard. QoL was evaluated using the Functional Assessment of Anorexia/Cachexia Therapy questionnaire. The statistical correlation between nutritional risk score (NRS) and oncological characteristics or QoL was evaluated using both univariable and multivariable analyses. Weight loss and reduction of food intake were the most frequent pathological nutritional indicators, while biochemical, inflammatory and functional variables were in the normal range. According to NRS, thirty-six patients were malnourished or at risk for malnutrition. Patients with NRS ≥ 3 presented a significantly greater percentage of stage IV gastric cancer and pathological values of C-reactive protein, while no correlation was found with the site of tumour. NRS was negatively associated with QoL (P < 0·001) and this relation was independent from oncological and inflammatory variables as confirmed by multivariable analysis. In the present study, we found that in patients with gastric cancer malnutrition is frequent at diagnosis and this is likely due to reduction in food intake. Moreover, NRS is directly correlated with tumour stage and inversely correlated with QoL, which makes it a useful tool to identify patients in need of an early nutritional intervention during oncological treatments.

Age-related cognitive decline (ARCD) and dementia are of increasing concern to an ageing population. In recent years, there has been considerable research focused on effective dietary interventions that may prevent or ameliorate ARCD and dementia. While a number of studies have considered the impact that dairy products may have on physiological health, particularly with regard to the metabolic syndrome and cardiovascular health, further research is currently needed in order to establish the impact that dairy products have in the promotion of healthy brain function during ageing. The present review considers the available evidence for the positive effects of dairy products on the metabolic syndrome and glucose regulation, with consideration of the implications for neurocognitive health. A literature search of current (September 2010) meta-analyses/reviews and original research regarding dairy products and cognition was conducted through SCOPUS using the following search terms for dairy consituents: dairy, milk, cheese, yoghurt, probiotics, whey protein, alpha lactalbumin, calcium, B-12, bioactive peptides and colostrinin (CLN). These search terms for dairy products were combined with the following search terms related to cognition and health: cognition, cognitive decline, dementia, Alzheimer's disease, metabolic syndrome, diabetes, insulin resistance and glucose regulation. Concerns regarding SFA and other fatty acids found in dairy products are also reviewed in relation to different forms of dairy products. The review also considers recent evidence for positive neurocognitive effects associated with bioactive peptides, CLN and proline-rich polypeptides, α-lactalbumin, vitamin B12, calcium and probiotics. Future directions for the extraction and purification of beneficial constituents are also discussed. It is concluded that low-fat dairy products, when consumed regularly as part of a balanced diet, may have a number of beneficial outcomes for neurocognitive health during ageing.

The objective of the present study was to determine whether the consumption of ≥ 250 v. < 250 mg of the long-chain n-3 fatty acids (n-3 LCFA) per d is associated with a reduction in the risk of fatal and non-fatal CHD in individuals with no prior history of CHD. A comprehensive and systematic review of the published scientific literature resulted in the identification of eight prospective studies (seven cohorts and one nested case–control study) that met predefined inclusion criteria. Relative to the consumption of < 250 mg n-3 LCFA per d, the consumption of ≥ 250 mg/d was associated with a significant 35·1 % reduction in the risk of sudden cardiac death and a near-significant 16·6 % reduction in the risk of total fatal coronary events, while the risk of non-fatal myocardial infarction was not significantly reduced. In several meta-analyses, which were based on US studies, risk of CHD death was found to be dose-dependently reduced by the n-3 LCFA, with further risk reductions observed with intakes in excess of 250 mg/d. Prospective observational and intervention data from Japan, where intake of fish is very high, suggest that n-3 LCFA intakes of 900 to 1000 mg/d and greater may confer protection against non-fatal myocardial infarction. Thus, the intake of 250 mg n-3 LCFA per d may, indeed, be a minimum target to be achieved by the general population for the promotion of cardiovascular health.

Fatty acid composition of the diet may influence cardiovascular risk from early childhood onwards. The objective of the present study was to perform a systematic review of dietary fat and fatty acid intakes in children and adolescents from different countries around the world and compare these with the population nutrient intake goals for prevention of chronic diseases as defined by the WHO (2003). Data on fat and fatty acid intake were mainly collected from national dietary surveys and from population studies all published during or after 1995. These were identified by searching PubMed, and through nutritionists at local Unilever offices in different countries. Fatty acid intake data from thirty countries mainly from developed countries were included. In twenty-eight of the thirty countries, mean SFA intakes were higher than the recommended maximum of 10 % energy, whereas in twenty-one out of thirty countries mean PUFA intakes were below recommended (6–10 % energy). More and better intake data are needed, in particular for developing regions of the world, and future research should determine the extent to which improvement of dietary fatty acid intake in childhood translates into lower CHD risk in later life. Despite these limitations, the available data clearly indicate that in the majority of the countries providing data on fatty acid intake, less than half of the children and adolescents meet the SFA and PUFA intake goals that are recommended for the prevention of chronic diseases.

Health claims for probiotics are evaluated by the Panel on Dietetic Products, Nutrition and Allergies of the European Food Safety Authority. Despite a substantial amount of basic and clinical research on the beneficial effects of probiotics, all of the evaluated claim applications thus far have received a negative opinion. With the restrictions on the use of clinical endpoints, validated biomarkers for gut health and immune health in relation to reduction in disease risk are needed. Clear-cut criteria for design as well as evaluation of future studies are needed. An open dialogue between basic and clinical scientists, regulatory authorities, food and nutrition industry, and consumers could bridge the gap between science and marketing of probiotics.

The North American Institute of Medicine (IOM) recently published their report on dietary reference intakes (DRI) for Ca and vitamin D. The DRI committee's deliberations underpinning this most comprehensive report on vitamin D nutrition to date benefited hugely from a much expanded knowledge base in vitamin D over the last decade or more. However, since their release, the vitamin D DRI have been the subject of intense controversy, which is largely due to the persistence of fundamental knowledge gaps in vitamin D. These can be identified at the levels of exposure, metabolism, storage, status, dose–response, function and beneficial or adverse health effects, as well as safe and effective application of intake recommendations at the population level through sustainable food-based approaches. The present review provides a brief overview of the approach used by the IOM committee to revise the DRI for vitamin D and to collate from a number of authoritative sources key knowledge gaps in vitamin D nutrition from the public health perspective. A number of research topics are outlined and data requirements within these are identified and mapped to the risk assessment framework used by the DRI committee. While not intended as an exhaustive list, it provides a basis for organising and prioritising research efforts in the area of vitamin D, which may offer a perspective on the major areas in need of attention. It is intended to be of use to researchers, national policy makers, the public health community, industry groups and other relevant stakeholders including funding institutions.

A recent meta-analysis of prospective cohort studies has not found an association between dietary saturated fat intake and CHD incidence. This funnelled the discussion about the importance of the recommendation to lower the intake of saturated fat for the prevention of CHD. At the same time a document of the European Food Safety Authority has suggested that specific quantitative recommendations are not needed for individual fatty acids but that more general statements can suffice. In this review, we discuss methodological aspects of the absence of association between SFA intake and CHD incidence in prospective cohort studies. We also summarise the results of the controlled dietary experiments on blood lipids and on CHD incidence in which saturated fat was replaced by either cis-unsaturated fat or carbohydrates. Finally, we propose a nutritionally adequate diet with an optimal fatty acid composition for the prevention of CHD in the context of dietary patterns. Such diets are characterised by a low intake of saturated fat, and as low as possible intake of trans-fat and fulfil the requirements for the intake of n-6 and n-3 fatty acids. No recommendation is needed for the intake of cis-MUFA.

Low-grade inflammation is a characteristic of the obese state, and adipose tissue releases many inflammatory mediators. The source of these mediators within adipose tissue is not clear, but infiltrating macrophages seem to be especially important, although adipocytes themselves play a role. Obese people have higher circulating concentrations of many inflammatory markers than lean people do, and these are believed to play a role in causing insulin resistance and other metabolic disturbances. Blood concentrations of inflammatory markers are lowered following weight loss. In the hours following the consumption of a meal, there is an elevation in the concentrations of inflammatory mediators in the bloodstream, which is exaggerated in obese subjects and in type 2 diabetics. Both high-glucose and high-fat meals may induce postprandial inflammation, and this is exaggerated by a high meal content of advanced glycation end products (AGE) and partly ablated by inclusion of certain antioxidants or antioxidant-containing foods within the meal. Healthy eating patterns are associated with lower circulating concentrations of inflammatory markers. Among the components of a healthy diet, whole grains, vegetables and fruits, and fish are all associated with lower inflammation. AGE are associated with enhanced oxidative stress and inflammation. SFA and trans-MUFA are pro-inflammatory, while PUFA, especially long-chain n-3 PUFA, are anti-inflammatory. Hyperglycaemia induces both postprandial and chronic low-grade inflammation. Vitamin C, vitamin E and carotenoids decrease the circulating concentrations of inflammatory markers. Potential mechanisms are described and research gaps, which limit our understanding of the interaction between diet and postprandial and chronic low-grade inflammation, are identified.

Evidence suggests that adipose tissue-derived adipokines induce mild inflammation and may play a role in insulin resistance associated with diabetes. The present study was designed to examine a series of adipokines and markers of inflammation in dogs before and after a successful weight loss. The study included fasting serum samples from twenty-five dogs before and after a weight-loss programme. Serum C-reactive protein (CRP) and monocyte chemoattractant protein-1 (MCP-1) were measured as indicators of chronic inflammation, while serum adipokines including total adiponectin, high-molecular-weight (HMW) adiponectin, resistin and leptin were also examined. Medians for CRP (before, 10·0 (interquartile range 5·4–15·0) μg/ml; after, 5·6 (interquartile range 3·8–7·0) μg/ml) and MCP-1 (before, 212 (interquartile range 157–288) ng/ml; after, 185 (interquartile range 143–215) ng/ml) decreased significantly after weight loss. Medians for resistin showed a mild, yet significant reduction (before, 67·1 (interquartile range 44·4–88·5) pg/ml; after, 60·5 (interquartile range 32·3–67·1) pg/ml), while leptin showed a dramatic decrease after weight loss (before, 18·9 (interquartile range 10·8–35·4) ng/ml; after, 6·6 (interquartile range 3·9–10·2) ng/ml). Serum total adiponectin and HMW adiponectin were unchanged on all analyses performed. These data suggest that weight loss can decrease chronic inflammation; however, the clinical implications of this decrease are not well elucidated in dogs. Surprisingly, there was no increase in total or HMW serum adiponectin after weight loss, as observed previously in human subjects. The lack of change in total and HMW adiponectin might explain why insulin resistance and type 2 diabetes are less prevalent in obese dogs when compared with humans and cats.

Dietary cholesterol comes exclusively from animal sources, thus it is naturally present in our diet and tissues. It is an important component of cell membranes and a precursor of bile acids, steroid hormones and vitamin D. Contrary to phytosterols (originated from plants), cholesterol is synthesised in the human body in order to maintain a stable pool when dietary intake is low. Given the necessity for cholesterol, very effective intestinal uptake mechanisms and enterohepatic bile acid and cholesterol reabsorption cycles exist; conversely, phytosterols are poorly absorbed and, indeed, rapidly excreted. Dietary cholesterol content does not significantly influence plasma cholesterol values, which are regulated by different genetic and nutritional factors that influence cholesterol absorption or synthesis. Some subjects are hyper-absorbers and others are hyper-responders, which implies new therapeutic issues. Epidemiological data do not support a link between dietary cholesterol and CVD. Recent biological data concerning the effect of dietary cholesterol on LDL receptor-related protein may explain the complexity of the effect of cholesterol on CVD risk.

The present study investigates the effects of genotype on responses to alternative feeds in Atlantic salmon. Microarray analysis of the liver transcriptome of two family groups, lean or fat, fed a diet containing either a fish oil (FO) or a vegetable oil (VO) blend indicated that pathways of cholesterol and lipoprotein metabolism might be differentially affected by the diet depending on the genetic background of the fish, and this was further investigated by real-time quantitative PCR, plasma and lipoprotein biochemical analysis. Results indicate a reduction in VLDL and LDL levels, with no changes in HDL, when FO is replaced by VO in the lean family group, whereas in fat fish fed FO, levels of apoB-containing lipoproteins were low and comparable with those fed VO in both family groups. Significantly lower levels of plasma TAG and LDL-TAG were measured in the fat group that was independent of diet, whereas plasma cholesterol was significantly higher in fish fed the FO diet in both groups. Hepatic expression of genes involved in cholesterol homeostasis, β-oxidation and lipoprotein metabolism showed relatively subtle changes. A significantly lower expression of genes considered anti-atherogenic in mammals (ATP-binding cassette transporter A1, apoAI, scavenger receptor class B type 1, lipoprotein lipase (LPL)b (TC67836) and LPLc (TC84899)) was found in lean fish, compared with fat fish, when fed VO. Furthermore, the lean family group appeared to show a greater response to diet composition in the cholesterol biosynthesis pathway, mediated by sterol-responsive element-binding protein 2. Finally, the presence of three different transcripts for LPL, with differential patterns of nutritional regulation, was demonstrated.

The developing fetus requires an adequate supply of fatty acids, in particular PUFA, for optimal growth and development. Little is known about the transfer of fatty acids by the placenta into the fetal circulation. However, the molecular form in which fatty acids are transferred into the fetal circulation may influence their metabolism and hence their availability to specific tissues. The aim of the present study was to determine which lipid pools in the fetal circulation become enriched in fatty acids from the placenta by comparing the fatty acid compositions of individual lipid pools between umbilical venous (UV) and umbilical arterial (UA) plasma. Plasma from the UV and UA was collected after delivery from ten uncomplicated pregnancies, and the fatty acid composition of each lipid class was determined by GC. Total NEFA concentration in the UV was twofold higher than in the UA (P < 0·05) due to enrichment in 16 : 0, 16 : 1n-7, 18 : 1n-9, 18 : 1n-7, 18 : 2n-6, 20 : 3n-6, 20 : 4n-6, 24 : 0 and 22 : 6n-3. Total cholesteryl ester concentration was twofold higher in the UV than in the UA (P < 0·05) due to enrichment in 16 : 0, 16 : 1n-7, 18 : 0, 18 : 1n-9, 18 : 1n-7, 18 : 2n-6 and 20 : 4n-6. There were no significant UV–UA differences in the total concentration or composition of TAG or phosphatidylcholine. The present study demonstrates differential enrichment across the placenta of fatty acids into specific lipid pools in the fetal circulation. Such partitioning may facilitate supply of individual fatty acids to specific fetal tissues.