'Doing school food!': a practical toolkit for adopting a whole school food approach

AIMS

The dietary intake and reported eating behaviours of adolescents in the UK are a public health concern. Schools are identified as an ideal 'place' setting to promote health and improve young peoples' nutrition outcomes. A gap in the understanding of how healthy secondary school food policy can be implemented, sustainable and effective, may hamper progress to improving school food provision and nutrition education in the UK. Research was conducted to understand the factors which influence healthy school food provision and the adolescent's food choice to inform and develop a practical framework for schools.

METHODS

This research involves the development of a practical toolkit which synthesises evidence generated from a mixed methods study and a systematic review. This was informed by an exploration of the secondary school food environment as a potentially 'obesogenic' setting, the effectiveness of school food interventions and policy in Europe and UK, included young people's (11-18 years of age) eating behaviours and priorities in food choice. A pragmatic approach was taken in the integration of evidence, using ecological and behaviour change theory, and joint display principles.

RESULT

A six-phase practical toolkit is presented, guided by 'What Good Looks Like' and 'Whole Systems Approach to Obesity' principles which can be used to translate the evidence from this research into good school food practice.

CONCLUSION

Improving secondary school food provision across the school day and having a coherent whole school food approach to healthy eating have the potential to significantly improve a young person's food choice, therefore impacting the nutrient intake of adolescents in the UK. This toolkit helps working towards operationalising this idea.

Environmental Pollution and the Risk of Developing Metabolic Disorders: Obesity and Diabetes

To meet the increased need for food and energy because of the economic shift brought about by the Industrial Revolution in the 19th century, there has been an increase in persistent organic pollutants (POPs), atmospheric emissions and metals in the environment. Several studies have reported a relationship between these pollutants and obesity, and diabetes (type 1, type 2 and gestational). All of the major pollutants are considered to be endocrine disruptors because of their interactions with various transcription factors, receptors and tissues that result in alterations of metabolic function. POPs impact adipogenesis, thereby increasing the prevalence of obesity in exposed individuals. Metals impact glucose regulation by disrupting pancreatic β-cells, causing hyperglycemia and impaired insulin signaling. Additionally, a positive association has been observed between the concentration of endocrine disrupting chemicals (EDCs) in the 12 weeks prior to conception and fasting glucose levels. Here, we evaluate what is currently known regarding the link between environmental pollutants and metabolic disorders. In addition, we indicate where further research is required to improve our understanding of the specific effects of pollutants on these metabolic disorders which would enable implementation of changes to enable their prevention.

Long-term Hyperandrogenemia and/or Western-style Diet in Rhesus Macaque Females Impairs Preimplantation Embryogenesis

Hyperandrogenemia and obesity are common in women with polycystic ovary syndrome, but it is currently unclear how each alone or in combination contribute to reproductive dysfunction and female infertility. To distinguish the individual and combined effects of hyperandrogenemia and an obesogenic diet on ovarian function, prepubertal female rhesus macaques received a standard control (C) diet, testosterone (T) implants, an obesogenic Western-style diet (WSD), or both (T + WSD). After 5 to 6 years of treatment, the females underwent metabolic assessments and controlled ovarian stimulations. Follicular fluid (FF) was collected for steroid and cytokine analysis and the oocytes fertilized in vitro. Although the T + WSD females exhibited higher insulin resistance compared to the controls, there were no significant differences in metabolic parameters between treatments. Significantly higher concentrations of CXCL-10 were detected in the FF from the T group, but no significant differences in intrafollicular steroid levels were observed. Immunostaining of cleavage-stage embryos revealed multiple nuclear abnormalities in the T, WSD, and T + WSD groups. Single-cell DNA sequencing showed that while C embryos contained primarily euploid blastomeres, most cells in the other treatment groups were aneuploid. Despite yielding a higher number of mature oocytes, T + WSD treatment resulted in significantly reduced blastocyst formation rates compared to the T group. RNA sequencing analysis of individual blastocysts showed differential expression of genes involved in critical implantation processes between the C group and other treatments. Collectively, we show that long-term WSD consumption reduces the capacity of fertilized oocytes to develop into blastocysts and that the addition of T further impacts gene expression and embryogenesis.

Consumption of dietary fat causes loss of olfactory sensory neurons and associated circuitry that is not mitigated by voluntary exercise in mice

Excess nutrition causes loss of olfactory sensory neurons (OSNs) and reduces odour discrimination and odour perception in mice. To separate diet-induced obesity from the consumption of dietary fat, we designed pair-feeding experiments whereby mice were maintained on isocaloric diets for 5 months, which prevented increased fat storage. To test our hypothesis that adiposity was not a prerequisite for loss of OSNs and bulbar projections, we used male and female mice with an odorant receptor-linked genetic reporter (M72tauLacZ; Olfr160) to visualize neural circuitry changes resulting from elevated fat in the diet. Simultaneously we monitored glucose clearance (diagnostic for prediabetes), body fat deposition, ingestive behaviours, select inflammatory markers and energy metabolism. Axonal projections to defined olfactory glomeruli were visualized in whole-mount brains, and the number of OSNs was manually counted across whole olfactory epithelia. After being pair fed a moderately high-fat (MHF) diet, mice of both sexes had body weight, adipose deposits, energy expenditure, respiratory exchange ratios and locomotor activity that were unchanged from control-fed mice. Despite this, they were still found to lose OSNs and associated bulbar projections. Even with unchanged adipocyte storage, pair-fed animals had an elevation in TNF cytokines and an intermediate ability for glucose clearance. Albeit improving health metrics, access to voluntary running while consuming an ad libitum fatty diet still precipitated a loss of OSNs and associated axonal projections for male mice. Our results support that long-term macronutrient imbalance can drive anatomical loss in the olfactory system regardless of total energy expenditure. KEY POINTS: Obesity can disrupt the structure and function of organ systems, including the olfactory system that is important for food selection and satiety. We designed dietary treatments in mice such that mice received fat, but the total calories provided were the same as in control diets so that they would not gain weight or increase adipose tissue. Mice that were not obese but consumed isocaloric fatty diets still lost olfactory neuronal circuits, had fewer numbers of olfactory neurons, had an elevation in inflammatory signals and had an intermediate ability to clear glucose (prediabetes). Mice were allowed access to running wheels while consuming fatty diets, yet still lost olfactory structures. We conclude that a long-term imbalance in nutrition that favours fat in the diet disrupts the olfactory system of mice in the absence of obesity.

Effects of Exercise Training on Renal Carnitine Biosynthesis and Uptake in the High-Fat and High-Sugar-Fed Mouse

(1) Background: Diet-induced obesity inhibits hepatic carnitine biosynthesis. Herein, the effects of high-fat (HF) and high-sugar (HFHS) feeding and exercise training (ET) on renal carnitine biosynthesis and uptake were determined. (2) Methods: Male C57BL/6J mice were assigned to the following groups: lean control (standard chow), HFHS diet, and HFHS diet with ET. ET consisted of 150 min of treadmill running per week for 12 weeks. Protein levels of γ-butyrobetaine hydroxylase (γ-BBH) and organic cation transporter-2 (OCTN2) were measured as markers of biosynthesis and uptake, respectively. (3) Results: HFHS feeding induced an obese diabetic state with accompanying hypocarnitinemia, reflected by decreased free carnitine levels in plasma and kidney. This hypocarnitinemia was associated with decreased γ-BBH (~30%) and increased OCTN2 levels (~50%). ET failed to improve the obesity and hyperglycemia, but improved insulin levels and prevented the hypocarnitinemia. ET increased protein levels of γ-BBH, whereas levels of OCTN2 were decreased. Peroxisome proliferator-activated receptor-alpha content was not changed by the HFHS diet or ET. (4) Conclusions: Our results indicate that ET prevents the hypocarnitinemia induced by HFHS feeding by increasing carnitine biosynthesis in kidney. Increased expression of OCTN2 with HFHS feeding suggests that renal uptake was stimulated to prevent carnitine loss.

Eating Occasions, Obesity and Related Behaviors in Working Adults: Does it Matter When You Snack?

Reported relationships between frequency, type, and timing of eating occasions and obesity-risk among adults are mixed while associations with obesogenic eating behaviors remain unexplored. The Physical Activity and Changes in Eating (PACE) study was a group-randomized controlled trial to prevent weight gain among 34 small worksites in Seattle from 2005-2009. Baseline surveys assessed body mass index (BMI), obesogenic eating behaviors (e.g., fast food and distracted-eating), and eating occasions (i.e., snacks and meals) among 2265 employees. BMI and waist circumference were measured on a subset (n = 567). Time-periods for analyses included: morning (12:00 a.m. to 10:59 a.m.), mid-day (11:00 a.m. to 4:29 p.m.), and evening (4:30 p.m. to 11:59 p.m.). Multilevel linear models estimated associations between snack timing, obesity, and related behaviors while adjusting for meal timing, gender, and worksite random effects. Greater morning snacking was associated with increased fruit and vegetable consumption, while greater evening snacking was associated with higher BMI, higher obesogenic dietary index (intake of fast food, French fries, and soft drinks), and higher percent time eating while distracted. Associations with mid-day snacking were mixed. Patterns of association were consistent across repeated and objective measures. Findings suggest that evening snacking is more detrimental to healthy weight compared to snacking at other times of day. Reducing evening snacks may be an important and simple message for population-level obesity prevention efforts.

Childhood obesity in Mexico: A critical analysis of the environmental factors, behaviours and discourses contributing to the epidemic

Mexico has the highest prevalence globally for children who are overweight. We conducted a qualitative study to understand childhood obesity in Mexico and the complex factors at play. Data were collected at three elementary schools in a low socio-economic area in Mexico City. Semi-structured interviews were conducted with 60 children, 24 parents and 28 teachers. The children interviewed were between the ages of 8 and 12 years old. Interview texts were analysed using NVivo 9 and 10 and thematic discourse analysis was used. Findings revealed how children’s choices around nutrition and physical activity were constrained by their environment and discursive constructions.

The Independent Associations between Walk Score® and Neighborhood Socioeconomic Status, Waist Circumference, Waist-To-Hip Ratio and Body Mass Index Among Urban Adults

Background: Environmental and policy factors can influence weight status via facilitating or discouraging physical activity and healthy diet. Despite mixed evidence, some findings suggest that the neighborhood built environment, including “walkability”, is associated with overweight and obesity. Most of these findings have measured body mass index (BMI), yet other weight status measures including waist circumference (WC) and waist-to-hip (W-H) ratio are also predictive of health outcomes, independent of BMI. Our study aim was to estimate the associations between walkability, measured using Walk Score^®, and each of WC, W-H ratio, and BMI among urban Canadian adults. Methods: In 2014, n = 851 adults recruited from 12 structurally and socioeconomic diverse neighborhoods (Calgary, Alberta, Canada) provided complete data on a physical activity, health and demographic questionnaire and self-reported anthropometric measures (i.e., height and weight, WC and hip circumference). Anthropometric data were used to estimate WC, W-H ratio, and BMI which were categorized into low and high risk in relation to their potential adverse effect on health. WC and BMI were also combined to provide a proxy measure of both overall and abdominal adiposity. Multivariable logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for associations between each weight status outcome and Walk Score^®. Results: A one-unit increase in Walk Score^® was associated with lower odds of being high-risk based on WC (OR = 0.99; 95%CI 0.97⁻0.99). Notably, those residing in socioeconomically disadvantage neighborhoods had significantly higher odds of being high risk based on WC, BMI, and WC-BMI combined compared with advantaged neighborhoods. Conclusions: Interventions that promote healthy weight through the design of neighborhoods that support and enhance the effect of physical activity and diet-related interventions could have a significant population health impact.

Social Gradients and Physical Activity Trends in an Obesogenic Dietary Pattern: Cross-Sectional Analysis of the UK National Diet and Nutrition Survey 2008-2014

An energy-dense, high-fat, low-fibre dietary pattern has been prospectively associated with the development of obesity in childhood but is population-specific, which limits translating the pattern into interventions. We explored the generalisability and correlates of this obesogenic dietary pattern in the UK National Diet and Nutrition Survey (NDNS) for the first time. Data came from participants (n = 4636 children and n = 4738 adults) with 4-day food diaries in NDNS 2008-2014. Reduced rank regression was applied to 51 food groups to explain variation in energy density, fibre and fat intake. Consistency of the pattern in population subgroups (according to sex, age, occupation and income) was compared with the whole sample pattern using coefficients of congruence (COC). Pattern correlates (sociodemographic, survey year, physical activity and eating related behaviours) were explored using multiple linear regression. Food group loadings were similar to the previously identified obesogenic dietary pattern and were generalisable across all sub-groups (COC: 0.93-0.99). An obesogenic diet was associated with eating takeaways, being omnivorous, a manual household occupation and lower household income in both adults and children (p < 0.0001). Dieting for weight loss, being older, more physically active and less sedentary was associated with a less obesogenic diet among adults (p < 0.0001). Future experimental studies should investigate if changes in this obesogenic pattern could be used to monitor the effectiveness of obesity prevention policies or develop personalised interventions.

Explaining recent mortality trends among younger and middle-aged White Americans

Background

Recent research has suggested that increases in mortality among middle-aged US Whites are being driven by suicides and poisonings from alcohol and drug use. Increases in these 'despair' deaths have been argued to reflect a cohort-based epidemic of pain and distress among middle-aged US Whites.

Methods

We examine trends in all-cause and cause-specific mortality rates among younger and middle-aged US White men and women between 1980 and 2014, using official US mortality data. We estimate trends in cause-specific mortality from suicides, alcohol-related deaths, drug-related deaths, 'metabolic diseases' (i.e. deaths from heart diseases, diabetes, obesity and/or hypertension), and residual deaths from extrinsic causes (i.e. causes external to the body). We examine variation in mortality trends by gender, age and cause of death, and decompose trends into period- and cohort-based variation.

Results

Trends in middle-aged US White mortality vary considerably by cause and gender. The relative contribution to overall mortality rates from drug-related deaths has increased dramatically since the early 1990s, but the contributions from suicide and alcohol-related deaths have remained stable. Rising mortality from drug-related deaths exhibit strong period-based patterns. Declines in deaths from metabolic diseases have slowed for middle-aged White men and have stalled for middle-aged White women, and exhibit strong cohort-based patterns.

Conclusions

We find little empirical support for the pain- and distress-based explanations for rising mortality in the US White population. Instead, recent mortality increases among younger and middle-aged US White men and women have likely been shaped by the US opiate epidemic and an expanding obesogenic environment.

RNA-Sequencing of Drosophila melanogaster Head Tissue on High-Sugar and High-Fat Diets

Obesity has been shown to increase risk for cardiovascular disease and type-2 diabetes. In addition, it has been implicated in aggravation of neurological conditions such as Alzheimer’s. In the model organism Drosophila melanogaster, a physiological state mimicking diet-induced obesity can be induced by subjecting fruit flies to a solid medium disproportionately higher in sugar than protein, or that has been supplemented with a rich source of saturated fat. These flies can exhibit increased circulating glucose levels, increased triglyceride content, insulin-like peptide resistance, and behavior indicative of neurological decline. We subjected flies to variants of the high-sugar diet, high-fat diet, or normal (control) diet, followed by a total RNA extraction from fly heads of each diet group for the purpose of Poly-A selected RNA-Sequencing. Our objective was to identify the effects of obesogenic diets on transcriptome patterns, how they differed between obesogenic diets, and identify genes that may relate to pathogenesis accompanying an obesity-like state. Gene ontology analysis indicated an overrepresentation of affected genes associated with immunity, metabolism, and hemocyanin in the high-fat diet group, and CHK, cell cycle activity, and DNA binding and transcription in the high-sugar diet group. Our results also indicate differences in the effects of the high-fat diet and high-sugar diet on expression profiles in head tissue of flies, despite the reportedly similar phenotypic impacts of the diets. The impacted genes, and how they may relate to pathogenesis in the Drosophila obesity-like state, warrant further experimental investigation.

Tributyltin and Zebrafish: Swimming in Dangerous Water

Zebrafish has been established as a reliable biological model with important insertion in academy (morphologic, biochemical, and pathophysiological studies) and pharmaceutical industry (toxicology and drug development) due to its molecular complexity and similar systems biology that recapitulate those from other organisms. Considering the toxicological aspects, many efforts using zebrafish models are being done in order to elucidate the effects of endocrine disruptors, and some of them are focused on tributyltin (TBT) and its mechanism of action. TBT is an antifouling agent applied in ship's hull that is constantly released into the water and absorbed by marine organisms, leading to bioaccumulation and biomagnification effects. Thus, several findings of malformations and changes in the normal biochemical and physiologic aspects of these marine animals have been related to TBT contamination. In the present review, we have compiled the most significant studies related to TBT effects in zebrafish, also taking into consideration the effects found in other study models.

Fitness, Fatness and Active School Commuting among Liverpool Schoolchildren

This study investigated differences in health outcomes between active and passive school commuters, and examined associations between parent perceptions of the neighborhood environment and active school commuting (ASC). One hundred-ninety-four children (107 girls), aged 9–10 years from ten primary schools in Liverpool, England, participated in this cross-sectional study. Measures of stature, body mass, waist circumference and cardiorespiratory fitness (CRF) were taken. School commute mode (active/passive) was self-reported and parents completed the neighborhood environment walkability scale for youth. Fifty-three percent of children commuted to school actively. Schoolchildren who lived in more deprived neighborhoods perceived by parents as being highly connected, unaesthetic and having mixed land-use were more likely to commute to school actively (p < 0.05). These children were at greatest risk of being obese and aerobically unfit (p < 0.01). Our results suggest that deprivation may explain the counterintuitive relationship between obesity, CRF and ASC in Liverpool schoolchildren. These findings encourage researchers and policy makers to be equally mindful of the social determinants of health when advocating behavioral and environmental health interventions. Further research exploring contextual factors to ASC, and examining the concurrent effect of ASC and diet on weight status by deprivation is needed.

Nurses' Perceptions of Weight Gain and Obesity in the Prison Environment

This study aimed to improve understanding of obesity in prison by investigating prison nurses' perceptions of weight gain and obesity. In-depth semistructured interviews were carried out with 17 nurses who worked in two male prisons in the United Kingdom. Nurses identified a variety of factors that they believed contributed to obesity and weight gain in the prison setting. These included factors caused by prisoner behavior, such as poor food choices and sedentary lifestyle. Factors influenced by the prison environment, such as stress of imprisonment, prison regime, and prison culture, were also seen as significant. These factors were seen as barriers to the role of nurses delivering care in prison. Nurses explained how they adapted their role to overcome these barriers.

Large Portions Encourage the Selection of Palatable Rather Than Filling Foods

BACKGROUND

Portion size is an important driver of larger meals. However, effects on food choice remain unclear.

OBJECTIVE

Our aim was to identify how portion size influences the effect of palatability and expected satiety on choice.

METHODS

In Study 1, adult participants (n = 24, 87.5% women) evaluated the palatability and expected satiety of 5 lunchtime meals and ranked them in order of preference. Separate ranks were elicited for equicaloric portions from 100 to 800 kcal (100-kcal steps). In Study 2, adult participants (n = 24, 75% women) evaluated 9 meals and ranked 100-600 kcal portions in 3 contexts (scenarios), believing that 1) the next meal would be at 1900, 2) they would receive only a bite of one food, and 3) a favorite dish would be offered immediately afterwards. Regression analysis was used to quantify predictors of choice.

RESULTS

In Study 1, the extent to which expected satiety and palatability predicted choice was highly dependent on portion size (P < 0.001). With smaller portions, expected satiety was a positive predictor, playing a role equal to palatability (100-kcal portions: expected satiety, β: 0.42; palatability, β: 0.46). With larger portions, palatability was a strong predictor (600-kcal portions: β: 0.53), and expected satiety was a poor or negative predictor (600-kcal portions: β: -0.42). In Study 2, this pattern was moderated by context (P = 0.024). Results from scenario 1 replicated Study 1. However, expected satiety was a poor predictor in both scenario 2 (expected satiety was irrelevant) and scenario 3 (satiety was guaranteed), and palatability was the primary driver of choice across all portions.

CONCLUSIONS

In adults, expected satiety influences food choice, but only when small equicaloric portions are compared. Larger portions not only promote the consumption of larger meals, but they encourage the adoption of food choice strategies motivated solely by palatability.

Barriers to Parent Support for Physical Activity in Appalachia

BACKGROUND

Parent support for child physical activity is a consistent predictor of increased childhood activity. Little is known about factors that prevent or facilitate support. The purpose of this research was to identify barriers to parent support for child physical activity in Appalachian parents.

METHODS

A cross-sectional study assessed parents whose children participated in Coronary Artery Risk Detection in Appalachian Communities (CARDIAC) screenings in a rural Appalachian state. Barriers to parental support for physical activity, demographics, geographic location, and parental support for activity were measured.

RESULTS

A total of 475 parents completed surveys. The majority were mothers (86.7%), parents of kindergarteners (49.5%), white (89.3%), and living in a nonrural area (70.5%). Community-level factors were most frequently cited as barriers, particularly those related to the built environment. Rural and low-income parents reported significantly higher barriers. Community, interpersonal, and intrapersonal barriers were negatively correlated with parent support for child physical activity. Parents of girls reported a higher percentage of barriers related to safety.

CONCLUSIONS

Reported barriers in this sample differed from those reported elsewhere (Davison, 2009). Specific groups such as low-income and rural parents should be targeted in intervention efforts. Future research should explore gender differences in reported barriers to determine the influence of cultural stereotypes.

A Pilot Study of Obesogenic Eating Behaviors in Children With Migraine

We studied associations between migraine severity and obesogenic eating behaviors in children with a prospective cross-sectional, clinic-based study. Migraine severity was quantified using the PedMIDAS tool and attack frequency. Eating behaviors were assessed using the Dutch Eating Behaviour Questionnaire and the Child Eating Behaviour Questionnaire. Food intake was assessed using a Food Intake Questionnaire. Statistical tests of association between eating behavior, food intake, and adiposity with migraine severity were performed. Sixty children (mean age = 10.9 years, standard deviation = 3.1; 26 males) were recruited. There was a positive correlation between the Child Eating Behaviour Questionnaire desire to drink subscale and PedMIDAS scores (r = 0.41, P = .01). Attack frequency was associated with higher intake of high fat or sugar content food and drink (r = 0.27, P = .04). No association between migraine severity and adiposity was found. Suggestion that migraine severity in children is associated with certain obesogenic eating behaviors requires further large study investigation.

Obesogenic environment: a concept analysis and pediatric perspective

PURPOSE

A concept analysis was undertaken to examine the attributes, characteristics, and uses of the concept of obesogenic environment within a pediatric context.

CONCLUSIONS

Utilizing a modified version of Walker and Avant's method, the attributes and characteristics of obesogenic environment were identified as it pertains to children. Based on the review of the literature and previous definitions applied to adults, a definition of the concept of obesogenic environment within a pediatric context was developed; examples of sample cases illustrate the concept further.

PRACTICE IMPLICATIONS

Defining the concept of obesogenic environment has utility for nursing theory development, practice, research, and education.

Drugs commonly associated with weight change: umbrella systematic review and meta-analysis (Protocol)

BACKGROUND

Many drugs and treatments given to patients for various reasons affect their weight. This side effect is of great importance to patients and is also a concern for the treating physician because weight change may lead to the emergence or worsening of other health conditions.

OBJECTIVE

The aim of this study is to summarize the evidence about commonly prescribed drugs and their association with weight change.

METHODS/DESIGN

Umbrella systematic review and meta-analysis of randomized controlled trials.We will use an umbrella approach to identify eligible randomized controlled trials (RCTs). We will search for systematic reviews of RCTs that compare any of the drugs that have been associated with weight gain (obesogenic) or weight loss (leptogenic); these have been summarized by our experts' panel in a predefined list. Two reviewers will independently determine RCT eligibility. Disagreement will be solved by consensus and arbitrated by a third reviewer. We will extract descriptive, methodological, and efficacy data in duplicate. Our primary continuous outcomes will be weight loss or gain expressed as a mean difference (MD) for weight (kg) or BMI (kg/m2). We will calculate the MD considering the mean difference in weight or BMI between baseline and the last available follow-up in both study arms (drugs and placebo). Our primary dichotomous outcome, presented as a relative risk, will compare the ratio of the incidence of weight change in each trial arm. When possible, results will be pooled using classic random-effects meta-analyses and a summary estimate with 95% confidence interval will provided. We will use the I2 statistic and Cochran's Q test to assess heterogeneity. The risk of bias will be assessed using the Cochrane risk of bias tool. Publication bias, if appropriate, will be evaluated, as well as overall strength of the evidence.

DISCUSSION

This systematic review will offer the opportunity to generate a ranking of commonly prescribed drugs in terms of their effect on weight, allowing guideline developers and patient-physician dyad to choose between available therapies.

Do interactions between gut ecology and environmental chemicals contribute to obesity and diabetes?

BACKGROUND

Gut microbiota are important factors in obesity and diabetes, yet little is known about their role in the toxicodynamics of environmental chemicals, including those recently found to be obesogenic and diabetogenic.

OBJECTIVES

We integrated evidence that independently links gut ecology and environmental chemicals to obesity and diabetes, providing a framework for suggesting how these environmental factors may interact with these diseases, and identified future research needs.

METHODS

We examined studies with germ-free or antibiotic-treated laboratory animals, and human studies that evaluated how dietary influences and microbial changes affected obesity and diabetes. Strengths and weaknesses of studies evaluating how environmental chemical exposures may affect obesity and diabetes were summarized, and research gaps on how gut ecology may affect the disposition of environmental chemicals were identified.

RESULTS

Mounting evidence indicates that gut microbiota composition affects obesity and diabetes, as does exposure to environmental chemicals. The toxicology and pharmacology literature also suggests that interindividual variations in gut microbiota may affect chemical metabolism via direct activation of chemicals, depletion of metabolites needed for biotransformation, alteration of host biotransformation enzyme activities, changes in enterohepatic circulation, altered bioavailability of environmental chemicals and/or antioxidants from food, and alterations in gut motility and barrier function.

CONCLUSIONS

Variations in gut microbiota are likely to affect human toxicodynamics and increase individual exposure to obesogenic and diabetogenic chemicals. Combating the global obesity and diabetes epidemics requires a multifaceted approach that should include greater emphasis on understanding and controlling the impact of interindividual gut microbe variability on the disposition of environmental chemicals in humans.