Toward an understanding of the role of the exposome on fragile X phenotypes

Fragile X syndrome (FXS) is the leading known monogenetic cause of autism with an estimated 21-50% of FXS individuals meeting autism diagnostic criteria. A critical gap in medical care for persons with autism is an understanding of how environmental exposures and gene-environment interactions affect disease outcomes. Our research indicates more severe neurological and metabolic outcomes (seizures, autism, increased body weight) in mouse and human models of autism spectrum disorders (ASD) as a function of diet. Thus, early-life exposure to chemicals in the diet could cause or exacerbate disease outcomes. Herein, we review the effects of potential dietary toxins, i.e., soy phytoestrogens, glyphosate, and polychlorinated biphenyls (PCB) in FXS and other autism models. The rationale is that potentially toxic chemicals in the diet, particularly infant formula, could contribute to the development and/or severity of ASD and that further study in this area has potential to improve ASD outcomes through dietary modification.

Large household reduces dementia mortality: A cross-sectional data analysis of 183 populations

BACKGROUND

Large households/families may create more happiness and offer more comprehensive healthcare among the members. We correlated household size to dementia mortality rate at population level for analysing its protecting role against dementia mortality.

METHODS

This is a retrospective cross-sectional study. Dementia specific mortality rates of the 183 member states of World Health Organization were calculated and matched with the respective country data on household size, Gross Domestic Product (GDP), urban population and ageing. Scatter plots were produced to explore and visualize the correlations between household size and dementia mortality rates. Pearson's and nonparametric correlations were used to evaluate the strength and direction of the associations between household size and all other variables. Partial correlation of Pearson's approach was used to identify that household size protects against dementia regardless of the competing effects from ageing, GDP and urbanization. Multiple regression was used to identify significant predictors of dementia mortality.

RESULTS

Household size was in a negative and moderately strong correlation (r = -0.6034, p < 0.001) with dementia mortality. This relationship was confirmed in both Pearson r (r = - 0.524, p<0.001) and nonparametric (rho  =  -0.579, p < 0.001) analyses. When we controlled for the contribution of ageing, socio-economic status and urban lifestyle in partial correlation analysis, large household was still in inverse and significant correlation to dementia mortality (r = -0.331, p <0.001). This suggested that, statistically, large household protect against dementia mortality regardless of the contributing effects of ageing, socio-economic status and urban lifestyle. Stepwise multiple regression analysis selected large household as the variable having the greatest contribution to dementia mortality with R2 = 0.263 while ageing was placed second increasing R2 to 0.259. GDP and urbanization were removed as having no statistically significant influence on dementia mortality.

CONCLUSIONS

While acknowledging ageing, urban lifestyle and greater GDP associated with dementia mortality, this study suggested that, at population level, household size was another risk factor for dementia mortality. As part of dementia prevention, healthcare practitioners should encourage people to increase their positive interactions with persons from their neighbourhood or other fields where large household/family size is hard to achieve.

Caryocar brasiliense Cambess. Pulp Oil Supplementation Reduces Total Cholesterol, LDL-c, and Non-HDL-c in Animals

The fruit of Caryocar brasiliense Cambess. is a source of oil with active compounds that are protective to the organism. In our work, we analyzed the physicochemical characteristics and evaluated the effects of supplementation with C. brasiliense oil in an animal model. We characterized the oil by indices of quality and identity, optical techniques of absorption spectroscopy in the UV–Vis region and fluorescence, and thermogravimetry/derived thermogravimetry (TG/DTG). For the animal experiment, we utilized mice (Mus musculus) supplemented with lipidic source in different dosages. The results demonstrated that C. brasiliense oil is an alternative source for human consumption and presents excellent oxidative stability. Primarily, it exhibited oleic MFA (53.56%) and palmitic SFA (37.78%). The oil level of tocopherols and tocotrienols was superior to the carotenoids. The supplementation with C. brasiliense oil reduced the levels of total cholesterol, LDL-c, and non-HDL-c. Regarding visceral fats and adiposity index, the treatment synergically supplemented with olive oil and C. brasiliense oil (OO + CO) obtained the best result. Therefore, C. brasiliense oil is a high quality product for consumption. Its supplementation promotes beneficial effects mainly on the lipidic profile.

Gluten consumption may contribute to worldwide obesity prevalence

Gluten consumption has been controversially associated with obesity in previous studies. We sought to examine this association at the worldwide level.

Country specific data were obtained from 168 countries. Scatter plots, bivariate, partial correlation and multiple linear regression models were used to explore and compare the coincidence between obesity prevalence and consumption of gluten, non-gluten cereal protein and total cereal protein respectively. The established risk factors of obesity: caloric intake, sedentary lifestyle, urbanization, socioeconomic status, meat protein intake and sugar consumption were included in analyses as potential confounders. The 168 countries were also stratified into developing and developed country groupings for further examination of the relationships.

Worldwide, bivariate correlation analyses revealed that the strength and direction of correlations between all variables (independent, dependent and potential confounders) were at similar levels. Obesity prevalence was positively correlated to gluten consumption but was negatively correlated to consumption of non-gluten cereal protein, and was in almost nil correlation to total cereal protein consumption. These relationships were similar across all countries (n= 168), developed country grouping (N=44) and developing country grouping (n=124). When caloric intake, Gross Domestic Product at Purchasing Power Parity, sedentary lifestyle and urbanization were kept statistically constant in the partial correlation analysis, obesity was significantly correlated to gluten consumption in all countries, developed country grouping and developing country grouping, and was significantly but inversely and weakly correlated to non-gluten cereal protein in all countries and developing countries, and was in almost nil correlation to total cereal protein in all country groupings. Globally, stepwise multiple regression analysis, when all the independent variables and potential confounding factors were included, selected consumption of sugar as the variable having the greatest influence on obesity with R2 = 0.510, while gluten was placed second increasing R2 to 0.596. Gluten consumption may have been emerging as an inconspicuous, but significant cause of obesity. While Westernization has driven the diet patterns worldwide to incorporate more gluten crops, obesity prevalence projection methods may estimate future obesity rates poorly if gluten consumption is not considered.

The Role of Dietary Phytoestrogens and the Nuclear Receptor PPARγ in Adipogenesis: An in Vitro Study

BACKGROUND

Phytoestrogens, naturally occurring plant chemicals, have long been thought to confer beneficial effects on human cardiovascular and metabolic health. However, recent epidemiological studies, have yielded conflicting outcomes, in which phytoestrogen consumption was both positively and negatively correlated with adiposity. Interestingly, several dietary phytoestrogens are known to stimulate or inhibit the activity of the peroxisome proliferator-activated receptor gamma (PPARγ), a key physiological regulator of adipogenesis.

OBJECTIVE

The objective of this study was to test the hypothesis that the pro- or anti-adipogenic activity of phytoestrogen chemicals is related to the ability to activate PPARγ in adipocytes.

METHODS

The effects of resveratrol and the soy isoflavones genistein and daidzein on adipogenesis were examined in cell-based assays using the 3T3-L1 cell model. In parallel, ligand-mediated alterations in PPARγ target gene expression were measured by quantitative polymerase chain reaction. The agonist/antagonist activities of phytoestrogens on PPARγ were further assessed by quantifying their ability to affect recruitment of transcriptional cofactors to the receptor.

RESULTS

Resveratrol displayed significant anti-adipogenic activities as exhibited by the ability to antagonize PPARγ-dependent adipocyte differentiation, down-regulate genes involved in lipid metabolism, block cofactor recruitment to PPARγ, and antagonize the effects of the PPARγ agonist rosiglitazone. In contrast, genistein and daidzein functioned as PPARγ agonists while also displaying pro-adipogenic activities.

CONCLUSIONS

These data provide biological evidence that the pro- or anti-obesity effects of phytoestrogens are related to their relative agonist/antagonist activity on PPARγ. Thus, PPARγ-activation assays may enable the screening of dietary components and identification of agents with adipogenic activities. https://doi.org/10.1289/EHP3444.

Increasing variability of body mass and health correlates in Swiss conscripts, a possible role of relaxed natural selection?

BACKGROUND AND OBJECTIVES

The body mass index (BMI) is an established anthropometric index for the development of obesity-related conditions. However, little is known about the distribution of BMI within a population, especially about this distribution's temporal change. Here, we analysed changes in the distribution of height, weight and BMI over the past 140 years based on data of Swiss conscripts and tested for correlations between anthropometric data and standard blood parameters.

METHODS

Height and weight were measured in 59 504 young Swiss males aged 18-19 years during conscription in 1875-79, 1932-36, 1994 and 2010-12. For 65% of conscripts in 2010-12, results of standard blood analysis were available. We calculated descriptive statistics of the distribution of height, weight and BMI over the four time periods and tested for associations between BMI and metabolic parameters.

RESULTS

Average and median body height, body weight and BMI increased over time. Height did no longer increase between 1994 and 2010-12, while weight and BMI still increased over these two decades. Variability ranges of weight and BMI increased over time, while variation of body height remained constant. Elevated levels of metabolic and inflammatory blood parameters were found at both ends of BMI distribution.

CONCLUSIONS AND IMPLICATIONS

Both overweight and underweight subgroups showed similar changes in inflammation parameters, pointing toward related metabolic deficiencies in both conditions. In addition to environmental influences, our results indicate a potential role of relaxed natural selection on genes affecting metabolism and body composition.

Lifelong exposure to dietary isoflavones reduces risk of obesity in ovariectomized Wistar rats

SCOPE

Traditional Asian diet rich in soy isoflavones (ISOs) is discussed to be linked to a lower obesity prevalence. In lifelong and short-term exposure scenarios we investigated effects of an ISO-rich diet on the body composition and development of obesity in female rats.

METHODS AND RESULTS

Female Wistar rats grew up on ISO-free or ISO-rich control diet (CON ISO: 467 mg/kg diet). Starting postnatal day 83, ovariectomized and intact animals received high calorie Western diet (WD) in the absence or presence of ISO (WD ISO: 431 mg/kg diet) for 12 weeks to induce obesity or maintained on respective control diet (CON). One group starting ISO exposure after ovariectomy mimics short-term ISO exposure in postmenopausal Western women. Lifelong but not short-term ISO exposure resulted in reduced body weight, visceral fat mass, serum leptin, and smaller adipocytes. ISO decreased hepatic SREBP-1c, ACC, FAS, and PPARγ mRNA expression in nonobese animals. Moreover, ovariectomy reduced skeletal muscle weight, which was antagonized by both short-term and lifelong ISO exposure.

CONCLUSION

Our results indicate that in female rats lifelong but not short-term ISO intake reduces the risk to develop obesity. Furthermore, lifelong and short-term ISO exposure may antagonize loss of skeletal muscle mass induced by ovariectomy.

Modern diet and metabolic variance--a recipe for disaster?

OBJECTIVE

Recently, a positive correlation between alanine transaminase activity and body mass was established among healthy young individuals of normal weight. Here we explore further this relationship and propose a physiological rationale for this link.

DESIGN

Cross-sectional statistical analysis of adiposity across large samples of adults differing by age, diet and lifestyle.

SUBJECTS

46,684 19-20 years old Swiss male conscripts and published data on 1000 Eskimos, 518 Toronto residents and 97,000 North American Adventists.

MEASUREMENTS

Serum concentrations of the alanine transaminase, post-prandial glucose levels, cholesterol, body height and weight, blood pressure and routine blood analysis (thrombocytes and leukocytes) for Swiss conscripts. Adiposity measures and dietary information for other groups were also obtained.

RESULTS

Stepwise multiple regression after correction for random errors of physiological tests showed that 28% of the total variance in body mass is associated with ALT concentrations. This relationship remained significant when only metabolically healthy (as defined by the American Heart Association) Swiss conscripts were selected. The data indicated that high protein only or high carbohydrate only diets are associated with lower levels of obesity than a diet combining proteins and carbohydrates.

CONCLUSION

Elevated levels of alanine transaminase, and likely other transaminases, may result in overactivity of the alanine cycle that produces pyruvate from protein. When a mixed meal of protein, carbohydrate and fat is consumed, carbohydrates and fats are digested faster and metabolised to satisfy body's energetic needs while slower digested protein is ultimately converted to malonyl CoA and stored as fat. Chronicity of this sequence is proposed to cause accumulation of somatic fat stores and thus obesity.

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.