Childhood obesity: behavioral aberration or biochemical drive? Reinterpreting the First Law of Thermodynamics

Trapped fat: Obesity pathogenesis as an intrinsic disorder in metabolic fuel partitioning

Our understanding of the pathophysiology of obesity remains at best incomplete despite a century of research. During this time, two alternative perspectives have helped shape thinking about the etiology of the disorder. The currently prevailing view holds that excessive fat accumulation results because energy intake exceeds energy expenditure, with excessive food consumption being the primary cause of the imbalance. The other perspective attributes the initiating cause of obesity to intrinsic metabolic defects that shift fuel partitioning from pathways for mobilization and oxidation to those for synthesis and storage. The resulting reduction in fuel oxidation and trapping of energy in adipose tissue drives a compensatory increase in energy intake and, under some conditions, a decrease in expenditure. This theory of obesity pathogenesis has historically garnered relatively less attention despite its pedigree. Here, we present an updated comprehensive formulation of the fuel partitioning theory, focused on evidence gathered over the last 80 years from major animal models of obesity showing a redirection of fuel fluxes from oxidation to storage and accumulation of excess body fat with energy intake equal to or even less than that of lean animals. The aim is to inform current discussions about the etiology of obesity and by so doing, help lay new foundations for the design of more efficacious approaches to obesity research, treatment and prevention.

Beyond Obesity and Overweight: The Clinical Assessment and Treatment of Excess Body Fat in Children : Part 1 - Insulin Resistance as the Root Cause of Pediatric Obesity

PURPOSE OF REVIEW

Pediatric obesity and comorbidities related to insulin resistance continue to be a growing public health crisis. If lifestyle measures are unsuccessful, pharmacological and surgical interventions are offered. In this paper, we describe the driving force of the obesity crisis: hyperinsulinemia and the development of insulin resistance. We give historical background of key policy issues which have contributed to this pandemic as well as the physiologic mechanisms of insulin resistance. The prevalence of obesity will continue to rise unless the root cause of hyperinsulinemia is addressed.

RECENT FINDINGS

Current research on insulin resistance demonstrates that a decreased consumption of carbohydrates is an effective first-line dietary intervention for the treatment of obesity and related metabolic diseases. Evidence shows it is safe and beneficial. A low-carbohydrate eating pattern can be helpful to address pediatric obesity. However, there must be policy guardrails in place to ensure that this is a sustainable and viable option for children and their families. There must be a change in the nutritional environment to help individuals battle the chronic disease of obesity.

Effects of ketone bodies on energy expenditure, substrate utilization, and energy intake in humans

The potential of ketogenic approaches to regulate energy balance has recently gained attention since ketones may influence both energy expenditure and energy intake. In this narrative review, we summarized the most relevant evidence about the role of ketosis on energy expenditure, substrate utilization, and energy intake in humans. We considered different strategies to induce ketosis, such as fasting, dietary manipulation, and exogenous ketone sources. In general, ketosis does not have a major influence on energy expenditure but promotes a shift in substrate utilization towards ketone body oxidation. The strategies to induce ketosis by reduction of dietary carbohydrate availability (e.g., ketogenic diets) do not independently influence energy intake, being thus equally effective for weight loss as diets with higher carbohydrate content. In contrast, the intake of medium-chain triglycerides and ketone esters induces ketosis and appears to increase energy expenditure and reduce energy intake in the context of high carbohydrate availability. These latter strategies lead to slightly enhanced weight loss. Unfortunately, distinguishing the effects of the various ketogenic strategies per se from the effects of other physiological responses is not possible with the available human data. Highly controlled, inpatient studies using targeted strategies to isolate the independent effects of ketones are required to adequately address this knowledge gap.

Diabetes websites lack information on dietary causes, risk factors, and preventions for type 2 diabetes

Introduction

Type 2 diabetes (T2D) is a growing public health burden throughout the world. Many people looking for information on how to prevent T2D will search on diabetes websites. Multiple dietary factors have a significant association with T2D risk, such as high intake of added sugars, refined carbohydrates, saturated fat, and red meat or processed meat; and decreased intake of dietary fiber, and fruits/vegetables. Despite this dietary information being available in the scientific literature, it is unclear whether this information is available in gray literature (websites).

Objective

In this study, we evaluate the use of specific terms from diabetes websites that are significantly associated with causes/risk factors and preventions for T2D from three term categories: (A) dietary factors, (B) nondietary nongenetic (lifestyle-associated) factors, and (C) genetic (non-modifiable) factors. We also evaluate the effect of website type (business, government, nonprofit) on term usage among websites.

Methods

We used web scraping and coding tools to quantify the use of specific terms from 73 diabetes websites. To determine the effect of term category and website type on the usage of specific terms among 73 websites, a repeated measures general linear model was performed.

Results

We found that dietary risk factors that are significantly associated with T2D (e.g., sugar, processed carbohydrates, dietary fat, fruits/vegetables, fiber, processed meat/red meat) were mentioned in significantly fewer websites than either nondietary nongenetic factors (e.g., obesity, physical activity, dyslipidemia, blood pressure) or genetic factors (age, family history, ethnicity). Among websites that provided "eat healthy" guidance, one third provided zero dietary factors associated with type 2 diabetes, and only 30% provided more than two specific dietary factors associates with type 2 diabetes. We also observed that mean percent usage of all terms associated with T2D causes/risk factors and preventions was significantly lower among government websites compared to business websites and nonprofit websites.

Conclusion

Diabetes websites need to increase their usage of dietary factors when discussing causes/risk factors and preventions for T2D; as dietary factors are modifiable and strongly associated with all nondietary nongenetic risk factors, in addition to T2D risk.

Position statement on nutrition therapy for overweight and obesity: nutrition department of the Brazilian association for the study of obesity and metabolic syndrome (ABESO-2022)

Obesity is a chronic disease resulting from multifactorial causes mainly related to lifestyle (sedentary lifestyle, inadequate eating habits) and to other conditions such as genetic, hereditary, psychological, cultural, and ethnic factors. The weight loss process is slow and complex, and involves lifestyle changes with an emphasis on nutritional therapy, physical activity practice, psychological interventions, and pharmacological or surgical treatment. Because the management of obesity is a long-term process, it is essential that the nutritional treatment contributes to the maintenance of the individual's global health. The main diet-related causes associated with excess weight are the high consumption of ultraprocessed foods, which are high in fats, sugars, and have high energy density; increased portion sizes; and low intake of fruits, vegetables, and grains. In addition, some situations negatively interfere with the weight loss process, such as fad diets that involve the belief in superfoods, the use of teas and phytotherapics, or even the avoidance of certain food groups, as has currently been the case for foods that are sources of carbohydrates. Individuals with obesity are often exposed to fad diets and, on a recurring basis, adhere to proposals with promises of quick solutions, which are not supported by the scientific literature. The adoption of a dietary pattern combining foods such as grains, lean meats, low-fat dairy, fruits, and vegetables, associated with an energy deficit, is the nutritional treatment recommended by the main international guidelines. Moreover, an emphasis on behavioral aspects including motivational interviewing and the encouragement for the individual to develop skills will contribute to achieve and maintain a healthy weight. Therefore, this Position Statement was prepared based on the analysis of the main randomized controlled studies and meta-analyses that tested different nutrition interventions for weight loss. Topics in the frontier of knowledge such as gut microbiota, inflammation, and nutritional genomics, as well as the processes involved in weight regain, were included in this document. This Position Statement was prepared by the Nutrition Department of the Brazilian Association for the Study of Obesity and Metabolic Syndrome (ABESO), with the collaboration of dietitians from research and clinical fields with an emphasis on strategies for weight loss.

Food addiction, hormones and blood biomarkers in humans: A systematic literature review

BACKGROUND

Food addiction may play a role in rising obesity rates in connection with obesogenic environments and processed food availability, however the concept of food addiction remains controversial. While animal studies show evidence for addictive processes in relation to processed foods, most human studies are psychologically focussed and there is a need to better understand evidence for biological mechanisms of food addiction in humans. Several key hormones are implicated in models of food addiction, due to their key roles in feeding, energy metabolism, stress and addictive behaviours. This systematic literature review examines evidence for relationships between food addiction, hormones and other blood biomarkers.

METHODS

A series of literature searches was performed in Scopus, PsychInfo, MedLine, ProQuest, CINAHL and Web of Science. A total of 3111 articles were found, of which 1045 were duplicates. Articles were included if they contained a psychometric measurement of food addiction, such as the Yale Food Addiction Scale, as well as addressed the association between FA and hormones or blood biomarkers in humans. Articles were assessed for eligibility by two independent reviewers.

RESULTS

Sixteen studies were identified that examined relationships between food addiction and blood biomarkers, published between 2015 and 2021. Significant findings were reported for leptin, ghrelin, cortisol, insulin and glucose, oxytocin, cholesterol, plasma dopamine, thyroid stimulating hormone (TSH), haemoglobin A1c (HbA1c), triglyceride (TG), amylin, tumour necrosis factor alpha (TNF- α) and cholecystokinin (CCK). Methodological issues included small sample sizes and variation in obesity status, sex and mental health-related comorbidities. Due to methodological limitations, definite connections between FA, hormones and other blood biomarkers cannot yet be determined.

CONCLUSION

This systematic review identified preliminary evidence linking FA symptoms to hormones and other blood biomarkers related to feeding, addiction, and stress. However, due to the small number of studies and methodological limitations, further research is needed to evaluate biopsychosocial models of FA and to resolve controversies.

Daytime sleepiness, addictive-like eating, and obesity sequelae in Black and African American youth with obesity

OBJECTIVES

The purpose of the current study was to examine the association between poor sleep health (ie, excessive daytime sleepiness), obesity sequelae (ie, percent overweight and serum leptin levels), and addictive-like eating behaviors, an obesity phenotype, in a sample of Black/African American (B/AA) adolescents.

DESIGN

The current study analyzed archival baseline data from a sample of B/AA adolescents with obesity enrolled in a sequential randomized clinical trial.

SETTING

Data were collected in the participants' homes by trained research assistants unaware of treatment condition.

PARTICIPANTS

A sample of 181 B/AA adolescents with obesity between the ages of 12 and 16 years (M = 14.26, SD = 1.46) and having a body mass index (BMI) above the 95th percentile for age and gender were sampled.

MEASUREMENTS

Self-report measures included the Cleveland Adolescent Sleepiness Questionnaire and the Yale Food Addiction Scale-Children (YFAS-C). Anthropomorphic data and blood samples were used to determine BMI and serum leptin levels, respectively.

RESULTS

Excessive daytime sleepiness was positively correlated with YFAS-C symptom count, r = 0.295, P < .001. Serum leptin levels and percent overweight were both positively correlated with each other, r = 0.445, P < .001 and with YFAS-C symptom count, r = 0.215, P = .006. After controlling for age and gender, results supported an indirect effect from daytime sleepiness to both serum leptin levels (estimate = 2.210, SE = 0.932, P = .018) and percent overweight (estimate = 2.817, SE = 1.415, P = .046) through YFAS-C symptom count.

CONCLUSIONS

Culturally informed interventions on eating behaviors (ie, addictive-like eating) when excessive daytime sleepiness is reported are needed. Early intervention may help prevent the onset or worsening of obesity among adolescents.

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.

Fright but not fight‐or‐flight: Violent video games elevated stress markers, but did not impact muscle function, memory recall or food intake, in a randomized trial in healthy young men

Objectives

Regular video game playing has been linked with obesity, but the underlying mechanisms remain unclear. Drawing on evolutionary life history theory, we hypothesized that playing violent video games, through activating the stress response, might increase the immediate demand for fuel by muscle and brain tissue, resulting in elevated appetite and food consumption.

Methods

We randomized 71 young adult men to play video games, involving either violent content or nonviolent puzzle‐solving, for 1 h. Over this period, we measured stress markers (blood pressure [BP], heart rate, visual‐analogue scale [VAS] self‐ratings), muscle function (handgrip strength) and cognitive function (memory recall test). Appetite was assessed by VAS, and by food intake using a test‐meal after the intervention. Linear mixed‐effects models were fitted to assess group effects and group:time effects.

Results

During the intervention, the violent video game group showed elevated systolic BP (∆ = 4.7 mm Hg, 95% CI 1.0, 8.4) and reported feeling more alert but less calm or happy. They showed no difference in grip strength or memory recall. They reported lower feelings of “fullness” but consumed similar food‐energy during the test‐meal.

Conclusions

Although playing a video game with violent content elevated physiological and perceived stress markers compared with a nonviolent game, this was not associated with markers of altered fuel distribution toward two tissues (muscle and brain) that contribute to the “fight‐or‐flight” response. Rather than more energy being allocated to the brain overall, energy may have been reallocated within the brain. This may explain why there was no compensatory increase in energy intake in the violent video game group.

The energy balance model of obesity: beyond calories in, calories out

A recent Perspective article described the "carbohydrate-insulin model (CIM)" of obesity, asserting that it "better reflects knowledge on the biology of weight control" as compared with what was described as the "dominant energy balance model (EBM)," which fails to consider "biological mechanisms that promote weight gain." Unfortunately, the Perspective conflated and confused the principle of energy balance, a law of physics that is agnostic as to obesity mechanisms, with the EBM as a theoretical model of obesity that is firmly based on biology. In doing so, the authors presented a false choice between the CIM and a caricature of the EBM that does not reflect modern obesity science. Here, we present a more accurate description of the EBM where the brain is the primary organ responsible for body weight regulation operating mainly below our conscious awareness via complex endocrine, metabolic, and nervous system signals to control food intake in response to the body's dynamic energy needs as well as environmental influences. We also describe the recent history of the CIM and show how the latest "most comprehensive formulation" abandons a formerly central feature that required fat accumulation in adipose tissue to be the primary driver of positive energy balance. As such, the new CIM can be considered a special case of the more comprehensive EBM but with a narrower focus on diets high in glycemic load as the primary factor responsible for common obesity. We review data from a wide variety of studies that address the validity of each model and demonstrate that the EBM is a more robust theory of obesity than the CIM.

Targeted Lipidomics Reveal the Effect of Perchlorate on Lipid Profiles in Liver of High-Fat Diet Mice

Perchlorate, commonly available in drinking water and food, acts on the iodine uptake by the thyroid affecting lipid metabolism. High-fat diets leading to various health problems continually raise public concern. In the present study, liver lipid metabolism profiles and metabolic pathways were investigated in C57BL/6J mice chronically exposed to perchlorate using targeted metabolomics. Mice were fed a high-fat diet and treated orally with perchlorate at 0.1 mg/kg bw (body weight), 1 mg/kg bw and 10 mg/kg bw daily for 12 weeks. Perchlorate induced disorders of lipid metabolism in vivo and hepatic lipid accumulation confirmed by serum biochemical parameters and histopathological examination. There were 34 kinds of lipid in liver detected by UHPLC-MS/MS and key metabolites were identified by multivariate statistical analysis evaluated with VIP > 1, p-value < 0.05, fold change > 1.2 or < 0.8. Perchlorate low, medium and high dose groups were identified with 11, 7 and 8 significantly altered lipid metabolites compared to the control group, respectively. The results of the metabolic pathway analysis revealed that the differential metabolites classified into different experimental groups contribute to the glycerophospholipid metabolic pathway. These findings provide insights into the effects of perchlorate on lipid metabolism during long-term exposure to high-fat diets and contribute to the evaluation of perchlorate liver toxic mechanisms and health effects.

Obesity I: Overview and molecular and biochemical mechanisms

Obesity is a chronic, relapsing condition characterized by excess body fat. Its prevalence has increased globally since the 1970s, and the number of obese and overweight people is now greater than those underweight. Obesity is a multifactorial condition, and as such, many components contribute to its development and pathogenesis. This is the first of three companion reviews that consider obesity. This review focuses on the genetics, viruses, insulin resistance, inflammation, gut microbiome, and circadian rhythms that promote obesity, along with hormones, growth factors, and organs and tissues that control its development. It shows that the regulation of energy balance (intake vs. expenditure) relies on the interplay of a variety of hormones from adipose tissue, gastrointestinal tract, pancreas, liver, and brain. It details how integrating central neurotransmitters and peripheral metabolic signals (e.g., leptin, insulin, ghrelin, peptide YY_3-36) is essential for controlling energy homeostasis and feeding behavior. It describes the distinct types of adipocytes and how fat cell development is controlled by hormones and growth factors acting via a variety of receptors, including peroxisome proliferator-activated receptor-gamma, retinoid X, insulin, estrogen, androgen, glucocorticoid, thyroid hormone, liver X, constitutive androstane, pregnane X, farnesoid, and aryl hydrocarbon receptors. Finally, it demonstrates that obesity likely has origins in utero. Understanding these biochemical drivers of adiposity and metabolic dysfunction throughout the life cycle lends plausibility and credence to the "obesogen hypothesis" (i.e., the importance of environmental chemicals that disrupt these receptors to promote adiposity or alter metabolism), elucidated more fully in the two companion reviews.

Serum Fatty Acid-Binding Protein 4 Levels in Adolescents: Effect of Insulin Resistance

Background: Fatty acid-binding protein 4 (FABP4) is an adipokine that plays a causative role in obesity and diabetes. In a stratified cross-sectional study with adolescents, we explored whether changes in FABP4 are already present in lean adolescents, provided they display elements of insulin resistance (IR). Methods: Adolescents were divided in four groups according to body mass index and homeostasis model assessment-IR. Results: In metabolically unhealthy lean (MUL) adolescents (MUL, lean with IR), FABP4 was 33% higher than in healthy counterparts (metabolically healthy lean [MHL]). Obese adolescents without IR (metabolically healthy obesity [MHO]) had 50% higher levels of FABP4 than their lean counterparts (MHL), while levels of FABP4 in obese adolescents with IR (metabolically unhealthy obese [MUO]) were 220% higher than those of MUL adolescents. The differences were significant at least with P < 0.005. MUO > MHO > MUL. Our data demonstrate that the known FABP4 defect in adults with obesity also occurs in youth and even in lean adolescents, suggesting an early association between impaired glucose metabolism and FABP4 irrespective of body weight. FABP4 was more sensitive in discerning each of our 4 subgroups than either adiponectin or leptin. Moreover, evidence for a putative early adiponectin resistance in MUL suggests a combined defect in these adolescents that call for early detection and prevention of the metabolic disturbance that should stay away from concentrating only in subjects with obesity. Conclusions: Our data may serve to draw the considerable attention that is currently paid to FABP4 to the adolescent population, irrespective of the presence of obesity. Further studies with larger cohorts and analyses of visceral and liver fat are warranted.

Promoting Healthier Eating via Parental Communication: Development and Validation of the Active and Restrictive Parental Guidance Questionnaire (PARQ)

Parents are important sources of influence in the development of healthy eating among children and adolescents. Besides gatekeeping and modeling, parents serve as health educators and promoters, using intentional and persuasive communication to encourage healthier eating preferences and behaviors in children. Despite this, a lack of reliable and valid measures has limited the research on how parent-driven interpersonal communication about foods influence child food consumption outcomes. Building on the research in parental mediation of media consumption, and parenting practices in public health nutrition, this study details the development and validation of the active and restrictive parental guidance questionnaire with a sample of 246 children and adolescents at the scale development phase and another sample of 1,113 children and adolescents at the scale validation phase. Findings show that parents employ four communicative strategies to encourage a healthier diet: active guidance, general discussion, preventive restrictive guidance, and promotive restrictive guidance. The new measure was shown to have good validity and measurement model fit. Implications for future research are discussed.

Is Technical-Grade Chlordane an Obesogen?

The prevalence of obesity has tripled in recent decades and is now considered an alarming public health problem. In recent years, a group of endocrine disruptors, known as obesogens, have been directly linked to the obesity epidemic. Its etiology is generally associated with a sedentary lifestyle, a high-fat diet and genetic predisposition, but environmental factors, such as obesogens, have also been reported as contributors for this pathology. In brief, obesogens are exogenous chemical compounds that alter metabolic processes and/or energy balance and appetite, thus predisposing to weight gain. Although this theory is still recent, the number of compounds with suspected obesogenic activity has steadily increased over the years, though many of them remain a matter of debate. Technical-grade chlordane is an organochlorine pesticide widely present in the environment, albeit at low concentrations. Highly lipophilic compounds can be metabolized by humans and animals into more toxic and stable compounds that are stored in fat tissue and consequently pose a danger to the human body, including the physiology of adipose tissue, which plays an important role in weight regulation. In addition, technical-grade chlordane is classified as a persistent organic pollutant, a group of chemicals whose epidemiological studies are associated with metabolic disorders, including obesity. Herein, we discuss the emerging roles of obesogens as threats to public health. We particularly discuss the relevance of chlordane persistence in the environment and how its effects on human and animal health provide evidence for its role as an endocrine disruptor with possible obesogenic activity.

Early Life Adversity and Pubertal Timing: Implications for Cardiometabolic Health

OBJECTIVE

To identify early life adversity (ELA) risk factors for earlier pubertal timing, itself a risk factor for poor cardiometabolic health, and to determine whether such ELA-related risk may be mediated by pre-pubertal body mass index (BMI).

METHODS

Subjects included 426 female participants in a prospective birth cohort study, the NICHD Study of Early Child Care and Youth Development. Survival analysis models were fit to examine ELA exposures, representing childhood socioeconomic status (SES), maternal sensitivity, mother-child attachment, and negative life events, along with child health indicators and covariates, in relation to pubertal timing outcomes, including age at menarche and ages at Tanner stage II for breast and pubic hair development.

RESULTS

Higher childhood SES emerged as an independent predictor of older age at menarche, showing each one standard deviation increase in childhood SES corresponded to a 1.3% increase in age at menarche (factor change = 1.013; 1.003-1.022; p < .01), but did not predict breast or pubic hair development (ps > .05). In mediation analyses, indirect (mediated) effects of mother-child attachment on the pubertal timing outcomes, via pre-pubertal BMI, were all statistically significant (ps < .05).

CONCLUSIONS

Higher childhood SES predicted directly, and secure (vs. insecure) mother-child attachment predicted indirectly (via pre-pubertal BMI), later pubertal timing, suggesting these factors may protect girls from earlier pubertal development. By extension, clinical implications are that intervention strategies designed to lessen ELA- and pre-pubertal obesity-related risk may be effective in remediating life course pathways linking ELA, accelerated pubertal development, and cardiometabolic risk.

Thermodynamic assessment of allocation of energy and exergy of the nutrients for the life processes during pregnancy

Thermodynamic analyses are performed to quantify allocation of the nutritional energy and exergy to most of the life processes by pregnant mice. In these analyses, 'internal work performance' is calculated for the first time in the literature for metabolism during pregnancy and found substantially higher than the 'external work performance'. Variation of the daily entropy generation rates and the daily internal work performance rates during the course of pregnancy showed a highly similar phasic behaviour. With the progression of the pregnancy, external work performance decreased and second law efficiency increased significantly. On the 13th day of pregnancy, net energy extracted from the food at the cellular energy metabolism subsystem was 15·0 kJ; approximately 3 kJ of it was employed for daily internal work performance, 0·8 kJ was allocated to daily external work performance and 0·8 kJ was stored in the adipose tissue without entering into the cellular energy metabolism subsystem. Heat generation in association with internal and external work performance was 9·1 and 2·2 kJ, respectively. Energy, pertinent to the first law, and exergy (useful energy), pertinent to the second law, balances are described graphically, and comparison of these plots showed that the total exergy of the nutrients allocated to internal and external work performance and heat generation is substantially smaller in magnitude when compared with those of energy balance.

Environmental lipidomics: understanding the response of organisms and ecosystems to a changing world

BACKGROUND

Understanding the interaction between organisms and the environment is important for predicting and mitigating the effects of global phenomena such as climate change, and the fate, transport, and health effects of anthropogenic pollutants. By understanding organism and ecosystem responses to environmental stressors at the molecular level, mechanisms of toxicity and adaptation can be determined. This information has important implications in human and environmental health, engineering biotechnologies, and understanding the interaction between anthropogenic induced changes and the biosphere. One class of molecules with unique promise for environmental science are lipids; lipids are highly abundant and ubiquitous across nearly all organisms, and lipid profiles often change drastically in response to external stimuli. These changes allow organisms to maintain essential biological functions, for example, membrane fluidity, as they adapt to a changing climate and chemical environment. Lipidomics can help scientists understand the historical and present biofeedback processes in climate change and the biogeochemical processes affecting nutrient cycles. Lipids can also be used to understand how ecosystems respond to historical environmental changes with lipid signatures dating back to hundreds of millions of years, which can help predict similar changes in the future. In addition, lipids are direct targets of environmental stressors, for example, lipids are easily prone to oxidative damage, which occurs during exposure to most toxins.

AIM OF REVIEW

This is the first review to summarize the current efforts to comprehensively measure lipids to better understand the interaction between organisms and their environment. This review focuses on lipidomic applications in the arenas of environmental toxicology and exposure assessment, xenobiotic exposures and health (e.g., obesity), global climate change, and nutrient cycles. Moreover, this review summarizes the use of and the potential for lipidomics in engineering biotechnologies for the remediation of persistent compounds and biofuel production.

KEY SCIENTIFIC CONCEPT

With the preservation of certain lipids across millions of years and our ever-increasing understanding of their diverse biological roles, lipidomic-based approaches provide a unique utility to increase our understanding of the contemporary and historical interactions between organisms, ecosystems, and anthropogenically-induced environmental changes.

Identifying the relationship between biological, psychosocial and family markers associated with childhood obesity: Case-control "ANOBAS" study

The recent increase in childhood obesity prevalence rates illustrates the extreme relevance of biological, psychosocial and familial factors implicated in body weight status, which at the moment remain unclear. The study aims to compare biological, psychosocial and familial markers between preadolescents with obesity and their non-overweight peers, and explore the relationship with psychiatric diagnosis on these markers. Both groups were composed of 40% of males with a mean age of 10 years, and no differences in socio-demographic variables were found between groups. No sex differences were found on bio/psycho/family markers. While 48% (n = 24) of the preadolescents with obesity presented a DSM-IV diagnosis (OGD), only 2% (n = 1) of the non-overweight peers (NG) met diagnostic criteria. Significant differences were found for all bio/psycho/family markers among obese preadolescents with the exceptions of cortisol, peptide YY and maternal state-anxiety and depression. The preadolescents with obesity without a diagnosis (OGND) presented greater levels of leptin than NG (p = 0.01). For psychosocial markers, statistically significant differences were found between groups in the majority of the variables (p <  0.01), with the exception of trait anxiety where a tendency towards significance was revealed (p = 0.06). For family markers, we found statistically significant differences in emotional over-involvement (p = 0.01), with NG mothers presenting lower scores than OGD and OGND. Include psychosocial and family factors in obesity intervention programs is necessary. Also, health professionals working with children with obesity must take care to assess the presence of a psychiatric diagnosis amongst this population.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

Is there a relationship between PTSD and complicated obesity? A review of the literature

Recent research strongly supports the hypothesis that posttraumatic stress disorder (PTSD) can be accompanied by obesity and related metabolic disturbances. The mechanisms of these associations are however still not well defined, although disturbed functions in the sympathetic-adrenergic nervous system together with the disturbed release of hormones via the endocrine HPA (hypothalamic-pituitary-adrenal) axis apparently play a role. Leptin resistance and ghrelin excesses might contribute to a disturbed hypothalamic function, and also disturb other cerebral functions, leading to dysfunctional reward signaling and uncontrolled appetite combined with a tendency to alcohol abuse. Secondarily, cortisol stimulation will contribute to the development of central obesity which is known to facilitate the development of metabolic syndrome, including slightly increased levels of inflammatory biomarkers such as C-reactive protein and fibrinogen. While previous therapeutic strategies have focused on early psychotherapeutic interventions in PTSD, the present review emphasizes the importance of better therapeutic approaches regarding the somatic correlates of the syndrome. Strict regulation of dietary meals and food composition with minimal intake of sweets and saturated fat, as well as alcohol avoidance, can provide a basic therapeutic framework. A cognitive psychotherapeutic approach with graduated desensitization toward trigging factors, combined with pharmacotherapy, is discussed in the present review.

Management of hypothalamic disease in patients with craniopharyngioma

Patients with craniopharyngioma experience excess morbidity and mortality when compared with the background population and with other hypopituitary patients. Large, suprasellar tumours which form micropapillae into surrounding structures can cause hypothalamic damage before any therapeutic intervention; attempted gross total resection can lead to hypothalamic obesity, sleep disorders, thirst disorders and dysregulation of temperature as well as panhypopituitarism. The management of tumour bulk and the pathophysiology of hypothalamic complications have been reviewed extensively. We present a practical, clinical approach to management of hypothalamic disease in a patient with craniopharyngioma and highlight potential targets for future pharmacological or surgical intervention.

Convenience Behavior and Being Overweight in Adults: Development and Validation of the Convenience Behavior Questionnaire

The etiology of overweight and obesity is a mixture of genetic determinants, environmental factors, and health behaviors. Especially intra- and interpersonal inactive behaviors, here termed convenience, seems to play an important role. The objective was to develop and validate the Convenience Behavior Questionnaire (CBQ) to assess convenience-related items and their association with overweight and obesity in a large population. A sample of 1233 subjects aged 18–82 years from six population groups took part in a self-administered questionnaire. Test-retest reliability was estimated and the independent association between convenience-related items and overweight and obesity was investigated. Principal component analysis revealed three factors (avoidance behaviors, social interaction behaviors and domestic environmental factors) which explained 43.4% of the variance contributing to the CBQ. Cronbach's α ranged from 0.80–0.89. Test-retest reliability using intra-class correlation was acceptable ≥ 0.70. Forward stepwise logistic regression analysis, including gender, education level, age and TV viewing on weekends showed a positive relation of convenience behavior and overweight (OR: 1.40; 95% CI: 1.01–1.96; P = 0.048), while physical activity status was not significantly associated with overweight (OR: 1.09; 95% CI: 0.77–1.54; P = 0.629). The CBQ seems to be a reliable tool which considers non-traditional behaviors related to overweight development. Interestingly our findings revealed a better relationship between convenience-related behavior with overweight and obesity than the habitual physical activity score.

Inflammation Markers in Type 2 Diabetes and the Metabolic Syndrome in the Pediatric Population

PURPOSE OF REVIEW

Chronic inflammation, adipokines, and hepatokines have been identified as basis of insulin resistance and β cell failure in animal models. We present our current knowledge concerning the potential relationship between these cytokines, inflammation, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM) in the pediatric population.

RECENT FINDINGS

Pro-inflammatory cytokines related to insulin resistance and MetS in children are tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, interferon gamma, pigment epithelium-derived factor, chemerin, vaspin, and fetuin A. Anti-inflammatory cytokines associated with insulin resistance and MetS in children are leptin, adiponectin, omentin, fibroblast growth factor (FGF)-21, osteocalcin, and irisin. These anti-inflammatory cytokines are decreased (adiponectin, omentin, and osteocalcin) or increased (leptin, FGF-21, and irisin) in obesity suggesting a resistance state. TNF-α, fetuin A, and FGF-21 are altered in obese children with T2DM suggesting an involvement in β cell failure. These cytokines, adipokines, and hepatokines may be able to predict development of MetS and T2DM and have a potential therapeutic target ameliorating insulin resistance.

Obesity is not just elevated adiposity, it is also a state of metabolic perturbation

Nettle et al. miss the crucial difference between adaptive models of storing energy and explanations for the pathological metabolic state of obesity. I suggest that the association of food insecurity with obesity in women from industrialized settings is most likely due to reverse causation: Poverty reduces agency to resist obesogenic foods, and this scenario is compounded by perturbations of insulin metabolism stemming from high adiposity and lipogenic diets.

Pancreatic neuro-insular network in young mice revealed by 3D panoramic histology

AIMS/HYPOTHESIS

It has been proposed that the neuro-insular network enables rapid, synchronised insulin secretion. However, to date, acquiring the pancreatic tissue map to study the neural network remains a challenging task as there is a lack of feasible approaches for large-scale tissue analysis at the organ level. Here, we have developed 3-dimensional (3D) panoramic histology to characterise the pancreatic neuro-insular network in young mice.

METHODS

Pancreases harvested from young wild-type B6 mice (3 and 8 weeks old) and db/db mice (3 weeks old; db/db vs db/+) were used to develop 3D panoramic histology. Transparent pancreases were prepared by optical clearing to enable deep-tissue, tile-scanning microscopy for qualitative and quantitative analyses of islets and the pancreatic tissue network in space.

RESULTS

3D panoramic histology reveals the pancreatic neurovascular network and the coupling of ganglionic and islet populations via the network. This integration is identified in both 3- and 8-week-old mice, featuring the peri-arteriolar neuro-insular network and islet-ganglionic aggregation. In weaning hyperphagic db/db mice, the 3D image data identifies the associated increases in weight, adipose tissue attached to the pancreas, density of large islets (major axis > 150 μm) and pancreatic sympathetic innervation compared with db/+ mice.

CONCLUSIONS/INTERPRETATION

Our work provides insight into the neuro-insular integration at the organ level and demonstrates a new approach for investigating previously unknown details of the pancreatic tissue network in health and disease.

The ineluctable constraints of thermodynamics in the aetiology of obesity

We exploit the detail-independence feature of thermodynamics to examine issues related to the development of obesity. We adopt a 'global' approach consistent with focus on the first law of thermodynamics - namely that the metabolic energy provided by dietary foodstuffs has only three possible fates: the performance of work (be it microscopic or macroscopic), the generation of heat, or storage - primarily in the form of adipose tissue. Quantification of the energy expended, in the form of fat metabolised, during selected endurance events, reveals the inherent limitation of over-reliance on exercise as a primary agent of weight loss. This result prompts examination of various (non-exercise based) possibilities of increasing the rate of heat loss. Since these, too, give little cause for optimism, we are obliged to conclude that obesity can be prevented, or weight loss achieved, only if exercise is supplemented by reduction of food intake.

Obesity Pathogenesis: An Endocrine Society Scientific Statement

Obesity is among the most common and costly chronic disorders worldwide. Estimates suggest that in the United States obesity affects one-third of adults, accounts for up to one-third of total mortality, is concentrated among lower income groups, and increasingly affects children as well as adults. A lack of effective options for long-term weight reduction magnifies the enormity of this problem; individuals who successfully complete behavioral and dietary weight-loss programs eventually regain most of the lost weight. We included evidence from basic science, clinical, and epidemiological literature to assess current knowledge regarding mechanisms underlying excess body-fat accumulation, the biological defense of excess fat mass, and the tendency for lost weight to be regained. A major area of emphasis is the science of energy homeostasis, the biological process that maintains weight stability by actively matching energy intake to energy expenditure over time. Growing evidence suggests that obesity is a disorder of the energy homeostasis system, rather than simply arising from the passive accumulation of excess weight. We need to elucidate the mechanisms underlying this "upward setting" or "resetting" of the defended level of body-fat mass, whether inherited or acquired. The ongoing study of how genetic, developmental, and environmental forces affect the energy homeostasis system will help us better understand these mechanisms and are therefore a major focus of this statement. The scientific goal is to elucidate obesity pathogenesis so as to better inform treatment, public policy, advocacy, and awareness of obesity in ways that ultimately diminish its public health and economic consequences.

Evolutionary public health: introducing the concept

The emerging discipline of evolutionary medicine is breaking new ground in understanding why people become ill. However, the value of evolutionary analyses of human physiology and behaviour is only beginning to be recognised in the field of public health. Core principles come from life history theory, which analyses the allocation of finite amounts of energy between four competing functions-maintenance, growth, reproduction, and defence. A central tenet of evolutionary theory is that organisms are selected to allocate energy and time to maximise reproductive success, rather than health or longevity. Ecological interactions that influence mortality risk, nutrient availability, and pathogen burden shape energy allocation strategies throughout the life course, thereby affecting diverse health outcomes. Public health interventions could improve their own effectiveness by incorporating an evolutionary perspective. In particular, evolutionary approaches offer new opportunities to address the complex challenges of global health, in which populations are differentially exposed to the metabolic consequences of poverty, high fertility, infectious diseases, and rapid changes in nutrition and lifestyle. The effect of specific interventions is predicted to depend on broader factors shaping life expectancy. Among the important tools in this approach are mathematical models, which can explore probable benefits and limitations of interventions in silico, before their implementation in human populations.

Suppression of Ghrelin Exacerbates HFCS-Induced Adiposity and Insulin Resistance

High fructose corn syrup (HFCS) is widely used as sweetener in processed foods and soft drinks in the United States, largely substituting sucrose (SUC). The orexigenic hormone ghrelin promotes obesity and insulin resistance; ghrelin responds differently to HFCS and SUC ingestion. Here we investigated the roles of ghrelin in HFCS- and SUC-induced adiposity and insulin resistance. To mimic soft drinks, 10-week-old male wild-type (WT) and ghrelin knockout (Ghrelin^-/-) mice were subjected to ad lib. regular chow diet supplemented with either water (RD), 8% HFCS (HFCS), or 10% sucrose (SUC). We found that SUC-feeding induced more robust increases in body weight and body fat than HFCS-feeding. Comparing to SUC-fed mice, HFCS-fed mice showed lower body weight but higher circulating glucose and insulin levels. Interestingly, we also found that ghrelin deletion exacerbates HFCS-induced adiposity and inflammation in adipose tissues, as well as whole-body insulin resistance. Our findings suggest that HFCS and SUC have differential effects on lipid metabolism: while sucrose promotes obesogenesis, HFCS primarily enhances inflammation and insulin resistance, and ghrelin confers protective effects for these metabolic dysfunctions.

A review of the carbohydrate-insulin model of obesity

The carbohydrate-insulin model of obesity theorizes that diets high in carbohydrate are particularly fattening due to their propensity to elevate insulin secretion. Insulin directs the partitioning of energy toward storage as fat in adipose tissue and away from oxidation by metabolically active tissues and purportedly results in a perceived state of cellular internal starvation. In response, hunger and appetite increases and metabolism is suppressed, thereby promoting the positive energy balance associated with the development of obesity. Several logical consequences of this carbohydrate-insulin model of obesity were recently investigated in a pair of carefully controlled inpatient feeding studies whose results failed to support key model predictions. Therefore, important aspects of carbohydrate-insulin model have been experimentally falsified suggesting that the model is too simplistic. This review describes the current state of the carbohydrate-insulin model and the implications of its recent experimental tests.

Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men

BACKGROUND

The carbohydrate-insulin model of obesity posits that habitual consumption of a high-carbohydrate diet sequesters fat within adipose tissue because of hyperinsulinemia and results in adaptive suppression of energy expenditure (EE). Therefore, isocaloric exchange of dietary carbohydrate for fat is predicted to result in increased EE, increased fat oxidation, and loss of body fat. In contrast, a more conventional view that "a calorie is a calorie" predicts that isocaloric variations in dietary carbohydrate and fat will have no physiologically important effects on EE or body fat.

OBJECTIVE

We investigated whether an isocaloric low-carbohydrate ketogenic diet (KD) is associated with changes in EE, respiratory quotient (RQ), and body composition.

DESIGN

Seventeen overweight or obese men were admitted to metabolic wards, where they consumed a high-carbohydrate baseline diet (BD) for 4 wk followed by 4 wk of an isocaloric KD with clamped protein. Subjects spent 2 consecutive days each week residing in metabolic chambers to measure changes in EE (EEchamber), sleeping EE (SEE), and RQ. Body composition changes were measured by dual-energy X-ray absorptiometry. Average EE during the final 2 wk of the BD and KD periods was measured by doubly labeled water (EEDLW).

RESULTS

Subjects lost weight and body fat throughout the study corresponding to an overall negative energy balance of ∼300 kcal/d. Compared with BD, the KD coincided with increased EEchamber (57 ± 13 kcal/d, P = 0.0004) and SEE (89 ± 14 kcal/d, P < 0.0001) and decreased RQ (-0.111 ± 0.003, P < 0.0001). EEDLW increased by 151 ± 63 kcal/d (P = 0.03). Body fat loss slowed during the KD and coincided with increased protein utilization and loss of fat-free mass.

CONCLUSION

The isocaloric KD was not accompanied by increased body fat loss but was associated with relatively small increases in EE that were near the limits of detection with the use of state-of-the-art technology. This trial was registered at clinicaltrials.gov as NCT01967563.

When a Spoonful of Fallacies Helps the Sweetener Go Down: The Corn Refiner Association's Use of Straw-Person Arguments in Health Debates Surrounding High-Fructose Corn Syrup

The American public is increasingly concerned about risks associated with food additives like high-fructose corn syrup (HFCS). To promote its product as safe, the Corn Refiners Association (CRA) employed two forms of straw-person arguments. First, the CRA opportunistically misrepresented HFCS opposition as inept. Second, the CRA strategically chose to refute claims that were easier to defeat while remaining ambiguous about more complex points of contention. We argue that CRA's discursive contributions represented unreasonable yet sustainable use of straw-person arguments in debates surrounding health and risk.

The Obesities: An Overview of Convergent and Divergent Paradigms

The study of obesity lends itself to difficulties not only due to our imprecise ability to measure body composition, food consumption, and physical activity but also, even more important, due to complexities involved in defining and conceptualizing obesity. For centuries, obesity has been considered a disease, although researchers and clinicians cannot agree on definitions of "disease" or, if it is one, whether obesity is a disease of metabolism, inflammation, brown fat, chronobiology, the blood-brain barrier, the right brain, or even of infectious origin. The concept of "obesity" as a disease remains controversial to some because not everyone who has excess adipose tissue has any evidence of disease. Obesity, though, has also been considered a sin, a crime against society, an aesthetic crime, a self-inflicted disability, an example of body diversity, a failure in the regulation of energy balance, an appropriate or even inappropriate adaptation to our increasingly obesogenic environment, a genetic disorder, and a psychological/behavioral disorder of overeating involving self-regulation or even addiction. Five major paradigms-medical, sociocultural, evolutionary, environmental, and psychological/behavioral, all with their own subcategorical models-have been identified. All 5 paradigms are required because we are dealing not with "obesity" but with a plurality, the "obesities."

Windows of opportunity for physical activity in the prevention of obesity

Tackling increasing rates of obesity is likely to be a defining feature of health care over the next several decades. Adult obesity is a persistent and treatment-resistant problem. Consequently, an emerging theme in the literature is to commence prevention efforts earlier in the developmental time course. This view is based primarily on epidemiological data demonstrating a link between traits manifesting early during development and increased obesity risk in adulthood. Physical activity is a perennial factor in discussions of obesity prevention. However, the optimal timing and type of physical activity interventions to commence remains unclear. Critical developmental windows of plasticity may afford time-limited opportunities to shape body composition across the life course; however, physical activity has not been explicitly considered in these discussions. Although animal models suggest that physical activity commenced earlier in development has differential effects on obesity onset compared to physical activity commenced in adulthood, human research is lacking. In this conceptual review, we consider physical activity during critical developmental periods as a way to mitigate obesity risk later in life.

Neighborhood socioeconomic status during childhood versus puberty in relation to endogenous sex hormone levels in adult women

BACKGROUND

Socioeconomic adversity in early life is related to cardiovascular risk in adulthood; however, no studies have examined whether such adversity may be related to endogenous sex hormones, which are themselves associated with cardiovascular outcomes, or whether the timing of adversity exposures (childhood vs. puberty) matters.

OBJECTIVE

The goal of the current study was to separately examine neighborhood socioeconomic status (SES) during periods of childhood and puberty in relation to adulthood levels of endogenous sex hormones (estradiol [E2], testosterone), sex hormone binding globulin (SHBG), and a derived index of bioavailable testosterone (free androgen index).

METHODS

In a sample of 143 premenopausal women (mean age = 36.8 [SD = 5.5]; 51.7% White, 32.2% African American, 5.6% Latina, 7.0% Chinese, and 3.5% Filipina), retrospective reports of residential address information in designated periods of childhood and puberty were used to derive U.S. census-based neighborhood SES composite scores characterizing the socioeconomic environments of women during these periods.

RESULTS

In covariate-adjusted analyses, higher neighborhood SES in puberty predicted higher levels of SHBG in adulthood, but neighborhood SES during childhood did not (standardized regression coefficient = .24, p = .01 vs. standardized regression coefficient = .04, p = .75, respectively). Neighborhood SES was not predictive of other hormones (E2, testosterone, and free androgen index).

DISCUSSION

The current findings suggest that puberty may be a time of particular vulnerability to the effects of neighborhood SES on SHBG levels, which have been linked to cardiovascular risk factor profiles and atherosclerotic disease progression.

Weight changes following the diagnosis of type 2 diabetes: the impact of recent and past weight history before diagnosis. results from the Danish Diabetes Care in General Practice (DCGP) study

Aims

The association between recent and more distant weight changes before and after the diagnosis of type 2 diabetes has been little researched. The aim of this study is to determine the influence of patients’ weight history before diabetes diagnosis on the observed 6-year weight changes after diagnosis.

Methods

A clinical cohort study combined with self-reported past weight history. In total 885 patients aged ≥40 years and newly diagnosed with clinical type 2 diabetes were included. Body weight was measured immediately after diabetes diagnosis and again at the 6-year follow up examination (median, 5.7 years). At diagnosis patients reported their weight 1 year and 10 years previously, and also at the age of 20. Multivariate linear regression analyses controlled for 20 baseline patient characteristics.

Results

The median (interquartile range) age at diagnosis was 63.2 (53.9; 71.4) years. Median body weight was 80.0 (72.0; 90.0) kg 10 years before diagnosis, 85.0 (75.0; 95.0) kg 1 year before diagnosis, 82.4 (72.0; 94.0) kg at diagnosis, and 80.0 (70.0; 91.1) kg at 6-year follow up. Each kg of weight gain during the year preceding the diagnosis was associated with a weight change (95% CI) of -0.20 (-0.28; -0.13) kg during the follow up period. In all models age and body mass index at diagnosis predicted future weight changes, while the weight at age 20 (-0.01 (-0.06; 0.03) kg/kg), and the weight change from 10 years to 1 year before diagnosis (-0.01 (-0.06; 0.04) kg/kg), did not predict weight change after diagnosis.

Conclusions

During the first on average 5.7 years after diagnosis of type 2 diabetes, patients generally follow a course of declining average weight, and these weight developments are related primarily to recent weight changes, body mass index, and age, but not to the more distant weight history.

Effect of nine diets on xenobiotic transporters in livers of mice

1. Lifestyle diseases are often caused by inappropriate nutrition habits and attempted to be treated by polypharmacotherapy. Therefore, it is important to determine whether differences in diet affect the disposition of drugs. Xenobiotic transporters in the liver are essential in drug disposition. 2. In the current study, mice were fed one of nine diets for 3 weeks. The mRNAs of 23 known xenobiotic transporters in livers of mice were quantified by microarray analysis, and validated by branched DNA assay. The mRNAs of 15 transporters were altered by at least one diet. Diet-restriction (10) and the atherogenic diet (10) altered the expression of the most number of transporters, followed by western diet (8), high-fat diet (4), lab chow (2), high-fructose diet (2) and EFA-deficient diet (2), whereas the low n-3 FA diet had no effect on these transporters. Seven of the 11 xenobiotic transporters in the Slc family, three of four in the Abcb family, two of four in the Abcc family and all three in the Abcg family were changed significantly. 3. This first comprehensive study indicates that xenobiotic transporters are altered by diet, and suggests there are likely diet-drug interactions due to changes in the expression of drug transporters.

Comprehensive biomarker testing of glycemia, insulin resistance, and beta cell function has greater sensitivity to detect diabetes risk than fasting glucose and HbA1c and is associated with improved glycemic control in clinical practice

Blood-based biomarker testing of insulin resistance (IR) and beta cell dysfunction may identify diabetes risk earlier than current glycemia-based approaches. This retrospective cohort study assessed 1,687 US patients at risk for cardiovascular disease (CVD) under routine clinical care with a comprehensive panel of 19 biomarkers and derived factors related to IR, beta cell function, and glycemic control. The mean age was 53 ± 15, 42 % were male, and 25 % had glycemic indicators consistent with prediabetes. An additional 45 % of the patients who had normal glycemic indicators were identified with IR or beta cell abnormalities. After 5.3 months of median follow-up, significantly more patients had improved than worsened their glycemic status in the prediabetic category (35 vs. 9 %; P < 0.0001) and in the “high normal” category (HbA1c values of 5.5–5.6; 56 vs. 18 %, p < 0.0001). Biomarker testing can identify IR early, enable and inform treatment, and improve glycemic control in a high proportion of patients.

Our stolen figures: the interface of sexual differentiation, endocrine disruptors, maternal programming, and energy balance

This article is part of a Special Issue "Energy Balance". The prevalence of adult obesity has risen markedly in the last quarter of the 20th century and has not been reversed in this century. Less well known is the fact that obesity prevalence has risen in domestic, laboratory, and feral animals, suggesting that all of these species have been exposed to obesogenic factors present in the environment. This review emphasizes interactions among three biological processes known to influence energy balance: Sexual differentiation, endocrine disruption, and maternal programming. Sexual dimorphisms include differences between males and females in body weight, adiposity, adipose tissue distribution, ingestive behavior, and the underlying neural circuits. These sexual dimorphisms are controlled by sex chromosomes, hormones that masculinize or feminize adult body weight during perinatal development, and hormones that act during later periods of development, such as puberty. Endocrine disruptors are natural and synthetic molecules that attenuate or block normal hormonal action during these same developmental periods. A growing body of research documents effects of endocrine disruptors on the differentiation of adipocytes and the central nervous system circuits that control food intake, energy expenditure, and adipose tissue storage. In parallel, interest has grown in epigenetic influences, including maternal programming, the process by which the mother's experience has permanent effects on energy-balancing traits in the offspring. This review highlights the points at which maternal programming, sexual differentiation, and endocrine disruption might dovetail to influence global changes in energy balancing traits.

Latino children's body mass index at 2-3.5 years predicts sympathetic nervous system activity at 5 years

BACKGROUND

To understand whether the relationship between young children's autonomic nervous system (ANS) responses predicted their BMI, or vice versa, the association between standardized BMI (zBMI) at 2, 3.5, and 5 years of age and ANS reactivity at 3.5-5 years of age, and whether zBMI predicts later ANS reactivity or whether early ANS reactivity predicts later zBMI, was studied.

METHODS

Low-income, primarily Latino children (n=112) were part of a larger cohort study of mothers recruited during early pregnancy. Study measures included maternal prenatal weight, children's health behaviors (i.e., time watching television, fast food consumption, and time playing outdoors), children's height and weight at 2, 3.5, and 5 years, and children's ANS reactivity at 3.5 and 5 years. ANS measures of sympathetic nervous system (i.e., pre-ejection period) and parasympathetic nervous system (i.e., respiratory sinus arrhythmia) activity were monitored during rest and four challenges. Reactivity was calculated as the difference between mean challenge response and rest. Structural equation models analyzed the relationship between children's zBMI at 2, 3.5, and 5 years and ANS reactivity at 3.5 and 5 years, adjusting for mother's BMI, children's behaviors, and changes in height.

RESULTS

There was no association between zBMI and ANS cross-sectionally. Children with high zBMI at 2 or 3.5 years or large zBMI increases from 2 to 3.5 years of age had decreased sympathetic activity at 5 years. Neither sympathetic nor parasympathetic reactivity at 3.5 years predicted later zBMI.

CONCLUSIONS

Increased zBMI early in childhood may dampen young children's SNS responses later in life.

Sugar consumption and global prevalence of obesity and hypertension: an ecological analysis

OBJECTIVE

The nutrition transition model provides an integrated approach to analyse global changes in food consumption and lifestyle patterns. Whether variability in food availability for consumption, lifestyle and sociodemographic factors is associated with the worldwide prevalence distribution of overweight, obesity and hypertension is unclear.

DESIGN

Ecological analysis.

SETTING

Country-specific prevalence estimates of overweight, obesity and hypertension were obtained. Prevalence estimates were then matched to year- and country-specific food and energy availability for consumption of cereals, sugar, sweeteners and honey, vegetable oils, fruits, starchy roots, pulses, total vegetables, alcoholic beverages, total meat, animal fat, eggs, milk, and fish and seafood. The per capita Gross Domestic Product (GDP), urbanization rates and prevalence of physical inactivity for each country were also obtained.

SUBJECTS

The overweight, obesity and hypertension databases included information from 128, 123 and seventy-nine countries, respectively.

RESULTS

Consumption of sugar and animal products were directly associated with GDP and urbanization rates. In a multivariate regression model, physical inactivity (B = 0·01, se = 0·005, P = 0·003), cereal consumption (B = -0·02, se = 0·006, P < 0·001) and sugar consumption (B = 0·03, se = 0·01, P = 0·03) were significant predictors of obesity prevalence. Midpoint age (B = 0·21, se = 0·10, P = 0·02), prevalence of overweight (B = 0·18, se = 0·08, P = 0·02) and consumption of cereals (B = -0·22, se = 0·10, P = 0·02) were significant predictors of hypertension. Women appeared to have a significant obesity excess compared with men.

CONCLUSIONS

High sugar consumption and sedentary lifestyle are associated with increased obesity prevalence. The non-linear association of sugar consumption with prevalence of obesity suggests that effective strategies to reduce its consumption may have differential effects in countries at different stages of the nutrition transition.

Nutrient intake of European adolescents: results of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study

OBJECTIVE

An adequate nutritional intake in childhood and adolescence is crucial for growth and the prevention of youth and adult obesity and nutrition-related morbidities. Improving nutrient intake in children and adolescents is of public health importance. The purpose of the present study was to describe and evaluate the nutrient intake in a European sample using the D-A-CH nutrient intake recommendations and the Nutritional Quality Index (NQI).

DESIGN

The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, the main objective of which is to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12·5-17·5 years.

SETTING

Eight cities in Europe.

SUBJECTS

The initial sample consisted of 3528 European adolescents. Among these, 1590 adolescents (54% female) had sufficient and plausible dietary data on energy and nutrient intakes from two 24 h recalls using the HELENA-DIAT software.

RESULTS

The intakes of most macronutrients, vitamins and minerals were in line with the D-A-CH recommendations. While the intakes of SFA and salt were too high, the intake of PUFA was too low. Furthermore, the intakes of vitamin D, folate, iodine and F were less than about 55% of the recommendations. The median NQI was about 71 (of a maximum of 100).

CONCLUSIONS

The intakes of most nutrients were adequate. However, further studies using suitable criteria to assess nutrient status are needed. Public health initiatives should educate children and adolescents regarding balanced food choices.

Height, adiposity and hormonal cardiovascular risk markers in childhood: how to partition the associations?

Objective:

Obesity is associated with rapid growth during childhood. There is uncertainty over how to adjust for body size, when using adiposity as a proxy for cardiovascular risk. We studied associations of height, body composition (by dual-energy X-ray absorptiometry) and cardiovascular risk markers (insulin resistance (IR), leptin) in children.

Methods:

Using partial correlations in 172 children aged 7–12 years, we investigated associations of (a) fat mass with IR or leptin, adjusting for height or lean mass, and (b) height or lean mass with IR or leptin, adjusting for fat mass. Analyses were conducted both cross-sectionally at each age, and for changes between 7 and 12 years.

Results:

Height, fat mass, lean mass, IR and leptin were all inter-correlated at all ages. Although fat mass was strongly associated with IR and leptin, height was independently negatively associated with leptin (whole sample, adjusting for age: boys r=−0.12, girls r=−0.13; P<0.001). Independent of adiposity, height was also associated with insulin IR (whole sample, adjusting for age: boys r=0.11, girls r=0.20; P<0.001). When analysed by year of age, these associations tended to remain significant at older ages. Change in height from 7 to 12 years was also associated with change in IR (boys: r=0.18, P<0.05; girls: r=0.34, P<0.01), independently of change in adiposity, with similar findings for lean mass.

Conclusions:

During childhood, markers of cardiovascular risk have a complex profile, associated with growth as well as fat accumulation. Taller and faster-growing children have elevated risk markers, independently of their adiposity. These findings have implications for the interpretation of pediatric indices of adiposity that aim to adjust for body size. Adiposity indices that perform best at summarizing metabolic risk may not be those that perform best at understanding the developmental aetiology of risk.

Ghrelin receptor regulates HFCS-induced adipose inflammation and insulin resistance

BACKGROUND AND OBJECTIVES

High fructose corn syrup (HFCS) is the most commonly used sweetener in the United States. Some studies show that HFCS consumption correlates with obesity and insulin resistance, while other studies are in disagreement. Owing to conflicting and insufficient scientific evidence, the safety of HFCS consumption remains controversial.

SUBJECTS/METHODS

We investigated the metabolic consequences of mice fed a (a) regular diet, (b) 'Western' high-fat diet or (c) regular diet supplemented with 8% HFCS in drinking water (to mimic soft drinks) for 10 months. Adipose tissue macrophages (ATMs) have emerged as a major pathogenic factor for obesity and insulin resistance. ATMs consist of proinflammatory F4/80(+)CD11c(+) macrophages and anti-inflammatory F4/80(+)CD11c(-) macrophages. In this study, we assessed the effects of HFCS on ATMs in intra-abdominal fat.

RESULTS

We found that HFCS feeding in mice induced more severe adipose inflammation and insulin resistance than even the higher-calorie-containing 'Western' high-fat diet, and these HFCS-induced deleterious effects were independent of calorie intake or body fat content. We showed that similar to 'Western' high-fat diet, HFCS triggered a robust increase of both proinflammatory ATMs and anti-inflammatory ATMs in intra-abdominal fat. Remarkably, however, the anti-inflammatory ATMs were much less abundant in HFCS-fed mice than in high-fat-fed mice. Furthermore, we showed that deletion of the ghrelin receptor (growth hormone secretagogue receptor, GHS-R) ameliorates HFCS-induced adipose inflammation and insulin resistance. HFCS-fed GHS-R-null mice exhibit decreased proinflammatory ATMs in intra-abdominal fat, reduced adipose inflammation and attenuated liver steatosis.

CONCLUSION

Our studies demonstrate that HFCS has detrimental effects on metabolism, suggesting that dietary guidelines on HFCS consumption for Americans may need to be revisited. GHS-R deletion mitigates the effects of HFCS on adipose inflammation and insulin resistance, suggesting that GHS-R antagonists may represent a novel therapy for insulin resistance.