Obesity--a disease with many aetiologies disguised in the same oversized phenotype: has the overeating theory failed?

Elevating the significance of legume intake: A novel strategy to counter aging-related mitochondrial dysfunction and physical decline

Mitochondrial dysfunction increasingly becomes a target for promoting healthy aging and longevity. The dysfunction of mitochondria with age ultimately leads to a decline in physical functions. Among them, biogenesis dysfunction and the imbalances in the metabolism of reactive oxygen species and mitochondria as signaling organelles in the aging process have aroused our attention. Dietary intervention in mitochondrial dysfunction and physical decline during aging processes is essential, and greater attention should be directed toward healthful legume intake. Legumes are constantly under investigation for their nutritional and bioactive properties, and their consumption may yield antiaging and mitochondria-protecting benefits. This review summarizes mitochondrial dysfunction with age, discusses the benefits of legumes on mitochondrial function, and introduces the potential role of legumes in managing aging-related physical decline. Additionally, it reveals the benefits of legume intake for the elderly and offers a viable approach to developing legume-based functional food.

Different Effects of High-Fat/High-Sucrose and High-Fructose Diets on Advanced Glycation End-Product Accumulation and on Mitochondrial Involvement in Heart and Skeletal Muscle in Mice

Diets with an elevated content of fat, sucrose, or fructose are recognized models of diet-induced metabolic alterations, since they induce metabolic derangements, oxidative stress, and chronic low-grade inflammation associated with local and systemic accumulation of advanced glycation end-products (AGEs). This study used four-week-old C57BL/6 male mice, randomly assigned to three experimental dietary regimens: standard diet (SD), high-fat high-sucrose diet (HFHS), or high fructose diet (HFr), administered for 12 weeks. Plasma, heart, and tibialis anterior (TA) skeletal muscle were assayed for markers of metabolic conditions, inflammation, presence of AGEs, and mitochondrial involvement. The HFHS diet induced a tissue-specific differential response featuring (1) a remarkable adaptation of the heart to HFHS-induced heavy oxidative stress, demonstrated by an increased presence of AGEs and reduced mitochondrial biogenesis, and efficaciously counteracted by a conspicuous increase in mitochondrial fission and PRXIII expression; (2) the absence of TA adaptation to HFHS, revealed by a heavy reduction in mitochondrial biogenesis, not counteracted by an increase in fission and PRXIII expression. HFr-induced mild oxidative stress elicited tissue-specific responses, featuring (1) a decrease in mitochondrial biogenesis in the heart, likely counteracted by a tendency for increased fission and (2) a mild reduction in mitochondrial biogenesis in TA, likely counteracted by a tendency for increased fusion, showing the adaptability of both tissues to the diet.

Does Oxidative Stress Along with Dysbiosis Participate in the Pathogenesis of Asthma in the Obese?

The most important environmental factor that can play a key role in the development of asthma in the obese is overproduction of reactive oxygen species (ROS). The aim of the study was to examine changes in the concentration of oxidative stress parameters in the lungs, bronchoalveolar lavage (BAL) fluid and blood of mice in models of asthma or/and obesity caused by high-fat diet (HFD). The concentrations of 4-HNE and isoprostanes in the lungs of the animals were measured. BAL fluid levels of hydrogen peroxide were marked. Additionally, thiobarbituric acid reactive substances (TBARS) and ferric reducing ability of plasma (FRAP) were used as biomarkers of oxidative stress in the blood. Administration of lipoic acid (LA), a probiotic with standard-fat diet (SFD, 10% fat) and low-fat diet (LFD, 5% fat) significantly decreased the concentration of 4-HNE as compared to the OVA (ovalbumin) + HFD group (p < 0.05). Treatment with low-fat diet or LFD in combination with apocynin insignificantly decreased H₂O₂ values as compared to the OVA + HFD group. Supplementation of probiotic with SFD and LFD significantly decreased the concentration of TBARS as compared to the OVA + SFD and saline + HDF groups (p < 0.05). Significantly lower concentrations of TBARS were also observed in the LA plus LFD group (p < 0.05) as compared to the OVA + HFD group. Low-fat diet with probiotic significantly increased the concentration of FRAP as compared to the obese mice (p = 0.017). Treatment with LFD in combination with LA significantly increased FRAP values as compared to the obese and obese asthmatic mice (p < 0.001).

Probiotic Mechanisms Affecting Glucose Homeostasis: A Scoping Review

The maintenance of a healthy status depends on the coexistence between the host organism and the microbiota. Early studies have already focused on the nutritional properties of probiotics, which may also contribute to the structural changes in the gut microbiota, thereby affecting host metabolism and homeostasis. Maintaining homeostasis in the body is therefore crucial and is reflected at all levels, including that of glucose, a simple sugar molecule that is an essential fuel for normal cellular function. Despite numerous clinical studies that have shown the effect of various probiotics on glucose and its homeostasis, knowledge about the exact function of their mechanism is still scarce. The aim of our review was to select in vivo and in vitro studies in English published in the last eleven years dealing with the effects of probiotics on glucose metabolism and its homeostasis. In this context, diverse probiotic effects at different organ levels were highlighted, summarizing their potential mechanisms to influence glucose metabolism and its homeostasis. Variations in results due to different methodological approaches were discussed, as well as limitations, especially in in vivo studies. Further studies on the interactions between probiotics, host microorganisms and their immunity are needed.

Competing paradigms of obesity pathogenesis: energy balance versus carbohydrate-insulin models

The obesity pandemic continues unabated despite a persistent public health campaign to decrease energy intake (“eat less”) and increase energy expenditure (“move more”). One explanation for this failure is that the current approach, based on the notion of energy balance, has not been adequately embraced by the public. Another possibility is that this approach rests on an erroneous paradigm. A new formulation of the energy balance model (EBM), like prior versions, considers overeating (energy intake > expenditure) the primary cause of obesity, incorporating an emphasis on “complex endocrine, metabolic, and nervous system signals” that control food intake below conscious level. This model attributes rising obesity prevalence to inexpensive, convenient, energy-dense, “ultra-processed” foods high in fat and sugar. An alternative view, the carbohydrate-insulin model (CIM), proposes that hormonal responses to highly processed carbohydrates shift energy partitioning toward deposition in adipose tissue, leaving fewer calories available for the body’s metabolic needs. Thus, increasing adiposity causes overeating to compensate for the sequestered calories. Here, we highlight robust contrasts in how the EBM and CIM view obesity pathophysiology and consider deficiencies in the EBM that impede paradigm testing and refinement. Rectifying these deficiencies should assume priority, as a constructive paradigm clash is needed to resolve long-standing scientific controversies and inform the design of new models to guide prevention and treatment. Nevertheless, public health action need not await resolution of this debate, as both models target processed carbohydrates as major drivers of obesity.

Effects of Intermittent Energy Restriction Alone and in Combination with Sprint Interval Training on Body Composition and Cardiometabolic Biomarkers in Individuals with Overweight and Obesity

The popularity of intermittent fasting (IF) and high intensity (sprint) interval training (SIT) has increased in recent years amongst the general public due to their purported health benefits and feasibility of incorporation into daily life. The number of scientific studies investigating these strategies has also increased, however, very few have examined the combined effects, especially on body composition and cardiometabolic biomarkers, which is the primary aim of this investigation. A total of thirty-four male and female participants (age: 35.4 ± 8.4 y, body mass index (BMI): 31.3 ± 3.5 kg/m2, aerobic capacity (VO2peak) 27.7 ± 7.0 mL·kg−1·min−1) were randomized into one of three 16-week interventions: (1) 5:2 IF (2 non-consecutive days of fasting per week, 5 days on ad libitum eating), (2) supervised SIT (3 bouts per week of 20s cycling at 150% VO2peak followed by 40 s of active rest, total 10 min duration), and (3) a combination of both interventions. Body composition, haemodynamic and VO2peak were measured at 0, 8 and 16 weeks. Blood samples were also taken and analysed for lipid profiles and markers of glucose regulation. Both IF and IF/SIT significantly decreased body weight, fat mass and visceral fat compared to SIT only (p < 0.05), with no significant differences between diet and diet + exercise combined. The effects of diet and/or exercise on cardiometabolic biomarkers were mixed. Only exercise alone or with IF significantly increased cardiorespiratory fitness. The results suggest that energy restriction was the main driver of body composition enhancement, with little effect from the low volume SIT. Conversely, to achieve benefits in cardiorespiratory fitness, exercise is required.

Calebin-A prevents HFD-induced obesity in mice by promoting thermogenesis and modulating gut microbiota

Background and aim

Obesity is one of the complications of sedentary lifestyle and high-calorie food intake which become a global problem. Thermogenesis is a novel way to promote anti-obesity by consuming energy as heat rather than storing it as triacylglycerols. Over the last decade, growing evidence has identified the gut microbiota as a potential factor in the pathophysiology of obesity. Calebin A is a non-curcuminoid novel compound derived from the rhizome of medicinal turmeric with putative anti-obesity effects. However, its ability on promoting thermogenesis and modulating gut microbiota remain unclear.

Experimental procedure

C57BL/6J mice were fed either normal diet or high-fat diet (HFD) supplement with calebin A (0.1 and 0.5%) diet for 12 weeks. The composition of the gut microbiota was assessed by analyzing 16S rRNA gene sequences.

Results and conclusion

Mice treated with calebin A shows a remarkable alteration in microbiota composition compared with that of normal diet-fed or HFD-fed mice and is characterized by an enrichment of Akkermansia, Butyricicoccus, Ruminiclostridium_9, and unidentified_Ruminococcaceae. We also explored that calebin A reduce the weight and blood sugar of mice that are induced by HFD, and show a dose-dependent reaction. Moreover, calebin A decreases the weight of white, beige, and brown adipose tissue, and also restores liver weight. In cold exposure experiments, calebin A can better maintain rectal temperature through thermogenesis. In summary, calebin A has a good thermogenesis function and is effective in anti-obesity. It can be used as a novel gut microbiota modulator to prevent HFD-induced obesity.

Offspring susceptibility to metabolic alterations due to maternal high-fat diet and the impact of inhaled ozone used as a stressor

The influence of maternal high-fat diet (HFD) on metabolic response to ozone was examined in Long-Evans rat offspring. F0 females were fed control diet (CD; 10%kcal from fat) or HFD (60%kcal from fat) starting at post-natal day (PND) 30. Rats were bred on PND 72. Dietary regimen was maintained until PND 30 when all offspring were switched to CD. On PND 40, F1 offspring (n = 10/group/sex) were exposed to air or 0.8 ppm ozone for 5 h. Serum samples were collected for global metabolomic analysis (n = 8/group/sex). Offspring from HFD dams had increased body fat and weight relative to CD. Metabolomic analysis revealed significant sex-, diet-, and exposure-related changes. Maternal HFD increased free fatty acids and decreased phospholipids (male > female) in air-exposed rats. Microbiome-associated histidine and tyrosine metabolites were increased in both sexes, while 1,5-anhydroglucitol levels decreased in males indicating susceptibility to insulin resistance. Ozone decreased monohydroxy fatty acids and acyl carnitines and increased pyruvate along with TCA cycle intermediates in females (HFD > CD). Ozone increased various amino acids, polyamines, and metabolites of gut microbiota in HFD female offspring indicating gut microbiome alterations. Collectively, these data suggest that maternal HFD increases offspring susceptibility to metabolic alterations in a sex-specific manner when challenged with environmental stressors.

Health impact of the Anthropocene: the complex relationship between gut microbiota, epigenetics, and human health, using obesity as an example

The growing prevalence of obesity worldwide poses a public health challenge in the current geological epoch, the Anthropocene. Global changes caused by urbanisation, loss of biodiversity, industrialisation, and land-use are happening alongside microbiota dysbiosis and increasing obesity prevalence. How alterations of the gut microbiota are associated with obesity and the epigenetic mechanism mediating this and other health outcome associations are in the process of being unveiled. Epigenetics is emerging as a key mechanism mediating the interaction between human body and the environment in producing disease. Evidence suggests that the gut microbiota plays a role in obesity as it contributes to different mechanisms, such as metabolism, body weight and composition, inflammatory responses, insulin signalling, and energy extraction from food. Consistently, obese people tend to have a different epigenetic profile compared to non-obese. However, evidence is usually scattered and there is a growing need for a structured framework to conceptualise this complexity and to help shaping complex solutions. In this paper, we propose a framework to analyse the observed associations between the alterations of microbiota and health outcomes and the role of epigenetic mechanisms underlying them using obesity as an example, in the current context of global changes within the Anthropocene.

Long-term sucrose solution consumption causes metabolic alterations and affects hepatic oxidative stress in Wistar rats

As the number of overweight and obese people has risen in recent years, there has been a parallel increase in the number of people with metabolic syndrome, diabetes and non-alcoholic fatty liver disease. The consumption of artificially sweetened beverages contributes to these epidemics. This study investigated the long-term effects of ingestion of a 40% sucrose solution on serum and hepatic parameters in male Wistar rats (Rattus norvegicus). After 180 days, the glycemic response, lipid profile and hepatic oxidative stress were compared to those of rats maintained on water. Sucrose ingestion led to higher body weight, increased fat deposits, reduced voluntary food intake and reduced feeding efficiency. Rats that received sucrose solution showed early signs of glucose intolerance and insulin resistance, such as hyperinsulinemia. Serum triacylglycerol (TG), very-low density lipoprotein (VLDL), cholesterol, ALT and AST levels increased after sucrose consumption. Elevated malondialdehyde and superoxide dismutase (SOD) levels and reduced glutathione levels characterize the hepatic oxidative stress due to sucrose ingestion. Liver sample histology showed vacuolar traces and increased fibrotic tissue. Our data showed the harmful effects of chronic consumption of sucrose solution, which can cause alterations that are found frequently in obesity, glucose intolerance and non-alcoholic hepatic disease, characteristics of metabolic syndrome.

Associations of Chronic Inflammation, Insulin Resistance, and Severe Obesity With Mortality, Myocardial Infarction, Cancer, and Chronic Pulmonary Disease

IMPORTANCE

Chronic inflammation and insulin resistance often accompany severe obesity, and all are associated with disease risk.

OBJECTIVE

To examine how the association of severe obesity with adverse outcomes may be modified by the presence of systemic inflammation and/or insulin resistance.

DESIGN, SETTING, AND PARTICIPANTS

This population-based, retrospective cohort study included all residents of Alberta, Canada, aged 18 years and older with at least 1 procedure to ascertain severe obesity and measures of C-reactive protein, fasting glucose, triglyceride, and high-density lipoprotein cholesterol levels. Participants were observed from April 2003 to March 2017, and data analysis was conducted from June 2018 to December 2018.

EXPOSURES

Severe obesity (body mass index ≥35 or ≥40 after January 1, 2017, as indicated with a procedure-fee modifier), chronic inflammation (all measures of C-reactive protein >10 mg/L), and a surrogate measure of insulin resistance.

MAIN OUTCOMES AND MEASURES

All-cause death, first acute myocardial infarction during follow-up, first cancer diagnosis during follow-up, and new chronic pulmonary disease.

RESULTS

Among 420 636 participants, the median age was 45 years (interquartile range, 34-56 years; range, 18-97 years), 157 799 (37.5%) were male, 185 782 (44.2%) had insulin resistance, 71 987 (17.1%) had severe obesity, and 10 770 (2.6%) had inflammation. In women with chronic inflammation, the presence of severe obesity was associated with a lower mortality risk (hazard ratio [HR], 0.75; 95% CI, 0.65-0.86), but there was no difference in risk in men with inflammation (HR, 0.89; 95% CI, 0.78-1.02). In contrast, the presence of severe obesity was associated with a higher mortality risk in men without inflammation (HR, 1.20; 95% CI, 1.13-1.26), but there was no difference in risk in women without inflammation (HR, 1.00; 95% CI, 0.95-1.06). For myocardial infarction, severe obesity was associated with increased risk in both women and men without inflammation (women: HR, 1.26; 95% CI, 1.17-1.36; men: HR, 1.35; 95% CI, 1.27-1.43) but not in women and men with inflammation (women: HR, 0.85; 95% CI, 0.67-1.07; men: HR, 0.90; 95% CI, 0.71-1.14). Severe obesity was associated with increased risk in women and men, irrespective of chronic inflammation, for new chronic pulmonary disease (women with inflammation: HR, 1.34; 95% CI, 1.23-1.46; women without inflammation: HR, 1.58; 95% CI, 1.54-1.62; men with inflammation: HR, 1.41; 95% CI, 1.29-1.54; men without inflammation: HR, 1.65; 95%, CI, 1.60-1.71) and cancer (women with inflammation: HR, 1.16; 95% CI, 1.03-1.30; women without inflammation, HR, 1.32; 95% CI, 1.28-1.36; men with inflammation: HR, 1.17; 95% CI, 1.04-1.32; men without inflammation: HR, 1.33; 95% CI, 1.28-1.39). Similar to chronic inflammation, severe obesity was not always associated with higher risk in participants with insulin resistance.

CONCLUSIONS AND RELEVANCE

The findings suggest that severe obesity with systemic inflammation is associated with a different prognosis than severe obesity without inflammation.

Obesity and Metabolic Syndrome in Kidney Transplantation: The Role of Dietary Fructose and Systemic Endotoxemia

BACKGROUND

The concepts that obesity is merely a consequence of overeating, and that metabolic health then reflects obesity, may be insufficient and potentially flawed. The role of fructose intake and metabolic endotoxemia has gained attention recently, but data in kidney transplantation are lacking. This study evaluated the risk factors for metabolic syndrome (MS), its components, and other associated markers in kidney transplant recipients (KTRs), focusing particularly on fructose intake and systemic endotoxemia.

METHODS

This cross-sectional observational study enrolled 128 KTRs longer than 1 year posttransplantation. Clinical, biochemical, anthropometric, and questionnaire assessments were undertaken.

RESULTS

Obesity (body mass index, ≥30 kg/m) and MS (International Diabetes Federation Definition) were found in 36.7% and 50% of KTRs, respectively. Both increased fructose intake (P = 0.01) and endotoxin level (P = 0.02) were independently associated with MS; and higher fructose intake was independently associated with obesity (P < 0.001). Specifically, increased fructose intake was associated with the central obesity (P = 0.01) and hyperglycemia (P < 0.001) criteria of MS, whereas higher endotoxin level was associated with the hypertriglyceridemia (P = 0.003) and low HDL cholesterol concentration (P = 0.002) criteria of MS. Neither saturated fat nor total caloric intakes were independently associated with obesity and MS; and neither obesity nor central obesity were independently associated with the dyslipidemia and hyperglycemia criteria of MS. Principal component analysis demonstrated relationships between higher levels of endotoxin, soluble endothelial selectin, triglycerides, and insulin resistance (r > 0.6), as well as relationships between increased fructose intake, inflammation, and blood glucose (r > 0.6).

CONCLUSIONS

Dietary modifications through decreasing fructose intake and addressing systemic endotoxemia are plausible targets for improving metabolic health of KTRs.

Case-control study of risk factors for pasture-and endocrinopathy-associated laminitis in North American horses

OBJECTIVE To investigate risk factors for the development of pasture- and endocrinopathy-associated laminitis (PEAL) in horses and ponies in North America. DESIGN Case-control study. ANIMALS 199 horses with incident cases of PEAL and 351 horses from 2 control populations (healthy horses [n = 198] and horses with lameness not caused by laminitis [153]) that were evaluated in North America between January 2012 and December 2015 by veterinarian members of the American Association of Equine Practitioners. PROCEDURES North American members of the American Association of Equine Practitioners were contacted to participate in the study, and participating veterinarians provided historical data on incident cases of PEAL, each matched with a healthy control and a lameness control. Conditional logistic regression analysis was used to compare data on PEAL-affected horses with data on horses from each set of controls. RESULTS Horses with an obese body condition (ie, body condition score ≥ 7), generalized or regional adiposity (alone or in combination), preexisting endocrinopathy, or recent (within 30 days) glucocorticoid administration had increased odds of developing PEAL, compared with horses that did not have these findings. CONCLUSIONS AND CLINICAL RELEVANCE The present study identified several risk factors for PEAL that may assist not only in managing and preventing this form of laminitis, but also in guiding future research into its pathogenesis.

Gut microbiota: a new path to treat obesity

Obesity is a multifactorial disease resulting in excessive accumulation of adipose tissue. Over the last decade, growing evidence has identified the gut microbiota as a potential factor in the pathophysiology of both obesity and the related metabolic disorders. The gut microbiota is known to protect gastrointestinal mucosa permeability and to regulate the fermentation and absorption of dietary polysaccharides, perhaps explaining its importance in the regulation of fat accumulation and the resultant obesity. The proposed mechanisms by which the gut microbiota could contribute to the pathogenesis of obesity and the related metabolic diseases include: (a) a high abundance of bacteria that ferment carbohydrates, leading to increased rates of short-chain fatty acid (SCFA) biosynthesis, providing an extra source of energy for the host, that is eventually stored as lipids or glucose; (b) increased intestinal permeability to bacterial lipopolysaccharides (LPS), resulting in elevated systemic LPS levels that aggravate low-grade inflammation and insulin resistance; (c) increased activity of the gut endocannabinoid system. Fecal transplantation studies in germ-free mice have provided crucial insights into the potential causative role of the gut microbiota in the development of obesity and obesity-related disorders. Diet +/- bariatric surgery have been reported to modulate the gut microbiota, leading to lean host phenotype body composition. This review aims to report clinical evidence for a link of the gut microbiota with human obesity and obesity-related diseases, to provide molecular insights into these associations, and to address the effect of diet and bariatric surgery on the gut microbiota, including colonic microbiota, as a potential mechanism for promoting weight loss.

Multi-etiological Perspective on Child Obesity Prevention

PURPOSE OF REVIEW

The simple energy balance model of obesity is inconsistent with the available findings on obesity etiology, prevention, and treatment. Yet, the most commonly stated causes of pediatric obesity are predicated on this model. A more comprehensive biological model is needed upon which to base behavioral interventions aimed at obesity prevention. In this light, alternative etiologies are little investigated and thereby poorly understood.

RECENT FINDINGS

Three candidate alternate etiologies are briefly presented: infectobesity, the gut microbiome, and circadian rhythms. Behavioral child obesity preventive investigators need to collaborate with biological colleagues to more intensively analyze the behavioral aspects of these etiologies and to generate innovative procedures for preventing a multi-etiological problem, e.g., group risk analysis, triaging for likely causes of obesity.

Basal Levels of Salivary Alpha-Amylase Are Associated with Preference for Foods High in Sugar and Anthropometric Markers of Cardiovascular Risk

Salivary alpha-amylase (sAA) influences the perception of taste and texture, features both relevant in acquiring food liking and, with time, food preference. However, no studies have yet investigated the relationship between basal activity levels of sAA and food preference. We collected saliva from 57 volunteers (63% women) who we assessed in terms of their preference for different food items. These items were grouped into four categories according to their nutritional properties: high in starch, high in sugar, high glycaemic index, and high glycaemic load. Anthropometric markers of cardiovascular risk were also calculated. Our findings suggest that sAA influences food preference and body composition in women. Regression analysis showed that basal sAA activity is inversely associated with subjective but not self-reported behavioural preference for foods high in sugar. Additionally, sAA and subjective preference are associated with anthropometric markers of cardiovascular risk. We believe that this pilot study points to this enzyme as an interesting candidate to consider among the physiological factors that modulate eating behaviour.

The Effect of Circadian and Sleep Disruptions on Obesity Risk

The prevalence of obesity continues to increase worldwide. Multiple risk factors and complex mechanisms are involved in the development and maintenance of obesity. Recently, emerging evidence has indicated that the circadian rhythm is important for regulating metabolism because the circadian system modulates energy metabolism and enhances certain energetic activities during day and night. Lifestyle also has a great impact on the circadian system. In addition to traditional risk factors, sleep and circadian disruptions are known modifiable risk factors for obesity and other metabolic disorders. This paper reviews recent evidence of relationships between energy metabolism and the circadian system and discusses how sleep disruption and circadian misalignment influence the development of obesity.

A high salt diet inhibits obesity and delays puberty in the female rat

BACKGROUND/OBJECTIVES

Processed foods are considered major contributors to the worldwide obesity epidemic. In addition to high sugar and fat contents, processed foods contain large amounts of salt. Owing to the correlations with rising adiposity, salt has recently been proposed to be obesogenic. This study investigated three hypotheses: (i) high salt contributes to weight gain and adiposity in juvenile female rats, (ii) puberty onset would be altered because salt is known to affect neuronal systems involved in activating the reproductive system, and (iii) enhanced adiposity will act synergistically with salt to drive early puberty onset.

DESIGN

Female weanling rats (post-natal day 21, n=105) were fed a low fat/low salt diet, low fat/high salt diet, high fat/low salt diet or a high salt/high fat diet for 24 days. Metabolic measures, including weight gain, food intake, fecal output, activity and temperature were recorded in subsets of animals.

RESULTS

Body weight, retroperitoneal and perirenal fat pad weight, and adipocyte size were all lower in animals fed high fat/high salt compared with animals fed high fat alone. Leptin levels were reduced in high fat/high salt fed animals compared with high fat/low salt-fed animals. Daily calorie intake was higher initially but declined with adjusted food intake and was not different among groups after 5 days. Osmolality and corticosterone were not different among groups. Fecal analysis showed excess fat excretion and a decreased digestive efficiency in animals fed high fat/low salt but not in animals fed high fat/high salt. Although respiratory exchange ratio was reduced by high dietary fat or salt, aerobic-resting metabolic rate was not affected by the diet. High salt delayed puberty onset, regardless of dietary fat content.

CONCLUSIONS

Salt delays puberty and prevents the obesogenic effect of a high fat diet. The reduced weight gain evident in high salt-fed animals is not due to differences in food intake or digestive efficiency.

DNA-Methylation and Body Composition in Preschool Children: Epigenome-Wide-Analysis in the European Childhood Obesity Project (CHOP)-Study

Adiposity and obesity result from the interaction of genetic variation and environmental factors from very early in life, possibly mediated by epigenetic processes. Few Epigenome-Wide-Association-Studies have identified DNA-methylation (DNAm) signatures associated with BMI and body composition in children. Body composition by Bio-Impedance-Analysis and genome-wide DNAm in whole blood were assessed in 374 pre-school children from four European countries. Associations were tested by linear regression adjusted for sex, age, centre, education, 6 WBC-proportions according to Houseman and 30 principal components derived from control probes. Specific DNAm variants were identified to be associated with BMI (212), fat-mass (230), fat-free-mass (120), fat-mass-index (24) and fat-free-mass-index (15). Probes in genes SNED1(IRE-BP1), KLHL6, WDR51A(POC1A), CYTH4-ELFN2, CFLAR, PRDM14, SOS1, ZNF643(ZFP69B), ST6GAL1, C3orf70, CILP2, MLLT4 and ncRNA LOC101929268 remained significantly associated after Bonferroni-correction of P-values. We provide novel evidence linking DNAm with (i) altered lipid and glucose metabolism, (ii) diabetes and (iii) body size and composition in children. Both common and specific epigenetic signatures among measures were also revealed. The causal direction with phenotypic measures and stability of DNAm variants throughout the life course remains unclear and longitudinal analysis in other populations is required. These findings give support for potential epigenetic programming of body composition and obesity.

Role of sleep and circadian disruption on energy expenditure and in metabolic predisposition to human obesity and metabolic disease

Weight gain, obesity and diabetes have reached alarming levels in the developed world. Traditional risk factors such as over-eating, poor nutritional choices and lack of exercise cannot fully account for the high prevalence of metabolic disease. This review paper examines the scientific evidence on two novel risk factors that contribute to dys-regulated metabolic physiology: sleep disruption and circadian misalignment. Specifically, fundamental relationships between energy metabolism and sleep and circadian rhythms and the impact of sleep and circadian disruption on metabolic physiology are examined. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic function, and many participate in shift work and social activities at times when the internal physiological clock is promoting sleep. These behaviours predispose an individual for poor metabolic health by promoting excess caloric intake in response to reduced sleep, food intake at internal biological times when metabolic physiology is not prepared, decreased energy expenditure when wakefulness and sleep are initiated at incorrect internal biological times, and disrupted glucose metabolism during short sleep and circadian misalignment. In addition to the traditional risk factors of poor diet and exercise, disturbed sleep and circadian rhythms represent modifiable risk factors for prevention and treatment of metabolic disease and for promotion of healthy metabolism.

Dietary Modeling of Foods for Advanced CKD Based on General Healthy Eating Guidelines: What Should Be on the Plate?

Chronic kidney disease (CKD) is a major public health problem with significant clinical, societal, and psychosocial burdens. Nutrition therapy has been an integral part of the medical management of patients with CKD for more than a century, with the main goals of preserving kidney function and preventing complications. Nutrition abnormalities may emerge well before dialysis therapy is initiated and are associated with poor outcomes. It is therefore important to revisit nutrition management in the advanced stages of CKD to gain a broader insight into its role and effect on patient outcomes. Traditionally, nutrition recommendations have focused on the prescription of energy (calories) and macro- and micronutrients. Today, dietary modeling also focuses on the evidence for food consumption on health. This review argues that advanced non-dialysis-dependent CKD nutrition requirements to a large extent align with healthy eating guidelines for the general population and should not be based on deprivation or be unusually restrictive. The best currently available evidence for the CKD diet is likely to be derived from CKD nutrition prescriptions in conjunction with evidence underpinning national dietary guidelines and evidence of healthy dietary patterns, such as Mediterranean-style and Dietary Approaches to Stop Hypertension (DASH)-style eating. Positive messages from these dietary patterns should improve acceptance of CKD dietary interventions among patients.

From Genome-Wide Association Study to Phenome-Wide Association Study: New Paradigms in Obesity Research

Obesity is a condition in which excess body fat has accumulated over an extent that increases the risk of many chronic diseases. The current clinical classification of obesity is based on measurement of body mass index (BMI), waist-hip ratio, and body fat percentage. However, these measurements do not account for the wide individual variations in fat distribution, degree of fatness or health risks, and genetic variants identified in the genome-wide association studies (GWAS). In this review, we will address this important issue with the introduction of phenome, phenomics, and phenome-wide association study (PheWAS). We will discuss the new paradigm shift from GWAS to PheWAS in obesity research. In the era of precision medicine, phenomics and PheWAS provide the required approaches to better definition and classification of obesity according to the association of obese phenome with their unique molecular makeup, lifestyle, and environmental impact.