Wheat gluten intake increases weight gain and adiposity associated with reduced thermogenesis and energy expenditure in an animal model of obesity

Gluten worsens non-alcoholic fatty liver disease by affecting lipogenesis and fatty acid oxidation in diet-induced obese apolipoprotein E-deficient mice

Obesity is closely associated with non-alcoholic fatty liver disease (NAFLD), characterized by hepatic fat accumulation and hepatocyte injury. Preclinical studies have shown exacerbated weight gain associated with an obesogenic gluten-containing diet. However, whether gluten affects obesity-induced hepatic lipid accumulation still remains unclear. We hypothesized that gluten intake could affect fatty liver development in high-fat diet (HFD)-induced obese mice. Thus, we aimed to investigate the impact of gluten intake on NAFLD in HFD-induced obese mice. Male apolipoprotein E-deficient (Apoe-/-) mice were fed with a HFD containing (GD) or not (GFD) vital wheat gluten (4.5%) for 10 weeks. Blood and liver were collected for further analysis. We found that gluten exacerbated weight gain, hepatic fat deposition, and hyperglycemia without affecting the serum lipid profile. Livers of the GD group showed a larger area of fibrosis, associated with the expression of collagen and MMP9, and higher expression of apoptosis-related factors, p53, p21, and caspase-3. The expression of lipogenic factors, such as PPARγ and Acc1, was more elevated and factors related to beta-oxidation, such as PPARα and Cpt1, were lower in the GD group compared to the GFD. Further, gluten intake induced a more significant expression of Cd36, suggesting higher uptake of free fatty acids. Finally, we found lower protein expression of PGC1α followed by lower activation of AMPK. Our data show that gluten-containing high-fat diet exacerbated NAFLD by affecting lipogenesis and fatty acid oxidation in obese Apoe-/- mice through a mechanism involving lower activation of AMPK.

Dietary wheat gluten induces astro- and microgliosis in the hypothalamus of male mice

Gluten, which is found in cereals such as wheat, rye and barley, makes up a major dietary component in most western nations, and has been shown to promote body mass gain and peripheral inflammation in mice. In the current study, we investigated the impact of gluten on central inflammation that is typically associated with diet-induced obesity. While we found no effect of gluten when added to a low-fat diet (LFD), male mice fed high fat diet (HFD) enriched with gluten increased body mass and adiposity compared with mice fed HFD without gluten. We furthermore found that gluten, when added to the LFD, increases circulating C-reactive protein levels. Gluten regardless of whether it was added to LFD or HFD led to a profound increase in the number of microglia and astrocytes in the arcuate nucleus of the hypothalamus, as detected by immunohistochemistry for ionised calcium binding adaptor molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP), respectively. In mice fed LFD, gluten mimicked the immunogenic effects of HFD exposure and when added to HFD led to a further increase in the number of immunoreactive cells. Taken together, our results confirm a moderate obesogenic effect of gluten when fed to mice exposed to HFD and for the first-time report gluten-induced astro- and microgliosis suggesting the development of hypothalamic injury in rodents.

Association of Fructo-oligosaccharides and Arginine Improves Severity of Mucositis and Modulate the Intestinal Microbiota

Mucositis is defined as inflammatory and ulcerative lesions along of the gastrointestinal tract that leads to the imbalance of the intestinal microbiota. The use of compounds with action on the integrity of the intestinal epithelium and their microbiota may be a beneficial alternative for the prevention and/or treatment of mucositis. So, the aim of this study was to evaluate the effectiveness of the association of fructo-oligosaccharides (FOS) and arginine on intestinal damage in experimental mucositis. BALB/c mice were randomized into five groups: CTL (without mucositis + saline), MUC (mucositis + saline), MUC + FOS (mucositis + supplementation with FOS-1st until 10th day), MUC + ARG (mucositis + supplementation with arginine-1st until 10th day), and MUC + FOS + ARG (mucositis + supplementation with FOS and arginine-1st until 10th day). On the 7th day, mucositis was induced with an intraperitoneal injection of 300 mg/kg 5-fluorouracil (5-FU), and after 72 h, the animals were euthanized. The results showed that association of FOS and arginine reduced weight loss and oxidative stress (P < 0.05) and maintained intestinal permeability and histological score at physiological levels. The supplementation with FOS and arginine also increased the number of goblet cells, collagen area, and GPR41 and GPR43 gene expression (P < 0.05). Besides these, the association of FOS and arginine modulated intestinal microbiota, leading to an increase in the abundance of the genera Bacteroides, Anaerostipes, and Lactobacillus (P < 0.05) in relation to increased concentration of propionate and acetate. In conclusion, the present results show that the association of FOS and arginine could be important adjuvants in the prevention of intestinal mucositis probably due to modulated intestinal microbiota.

Dietary gluten worsens hepatic steatosis by increasing inflammation and oxidative stress in ApoE-/- mice fed a high-fat diet

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disorder in the world. We have seen that gluten intake exacerbated obesity and atherosclerosis in apolipoprotein E knockout (ApoE-/-) mice. In this study, we investigated the effect of gluten consumption on inflammation and oxidative stress in the liver of mice with NAFLD. Male ApoE-/- mice were fed a gluten-free (GF-HFD) or gluten-containing (G-HFD) high-fat diet for 10 weeks. Blood, liver, and spleen were collected to perform the analyses. The animals of the gluten group had increased hepatic steatosis, followed by increased serum AST and ALT. Gluten intake increased hepatic infiltration of neutrophils, macrophages, and eosinophils, as well as the levels of chemotaxis-related factors CCL2, Cxcl2, and Cxcr3. The production of the TNF, IL-1β, IFNγ, and IL-4 cytokines in the liver was also increased by gluten intake. Furthermore, gluten exacerbated the hepatic lipid peroxidation and nitrotyrosine deposition, which were associated with increased production of ROS and nitric oxide. These effects were related to increased expression of NADPH oxidase and iNOS, as well as decreased activity of superoxide dismutase and catalase enzymes. There was an increased hepatic expression of the NF-κB and AP1 transcription factors, corroborating the worsening effect of gluten on inflammation and oxidative stress. Finally, we found an increased frequency of CD4+FOXP3+ lymphocytes in the spleen and increased gene expression of Foxp3 in the livers of the G-HFD group. In conclusion, dietary gluten aggravates NAFLD, exacerbating hepatic inflammation and oxidative stress in obese ApoE-deficient mice.

Staple Food Preference and Obesity Phenotypes: The Regional Ethnic Cohort Study in Northwest China

Staple food preference vary in populations, but evidence of its associations with obesity phenotypes are limited. Using baseline data (n = 105,840) of the Regional Ethnic Cohort Study in Northwest China, staple food preference was defined according to the intake frequency of rice and wheat. Overall and specifically abdominal fat accumulation were determined by excessive body fat percentage and waist circumference. Logistic regression and equal frequency substitution methods were used to evaluate the associations. We observed rice preference (consuming rice more frequently than wheat; 7.84% for men and 8.28% for women) was associated with a lower risk of excessive body fat (OR, 0.743; 95%CI, 0.669-0.826) and central obesity (OR, 0.886; 95%CI, 0.807-0.971) in men; and with lower risk of central obesity (OR, 0.898; 95%CI, 0.836-0.964) in women, compared with their wheat preference counterparties. Furthermore, similar but stronger inverse associations were observed in participants with normal body mass index. Wheat-to-rice (5 times/week) reallocations were associated with a 36.5% lower risk of normal-weight obesity in men and a 20.5% lower risk of normal-weight central obesity in women. Our data suggest that, compared with wheat, rice preference could be associated with lower odds ratios of certain obesity phenotypes in the Northwest Chinese population.

Differential Association of Wheat and Rice Consumption With Overweight/Obesity in Chinese Adults: China Health and Nutrition Survey 1991–2015

Wheat and rice are the main staple foods in China and likely have a major influence on health. This analysis examined the potential association between wheat and rice consumption and the risk of overweight/obesity in Chinese adults. We used data collected in the China Health and Nutrition Survey (CHNS) from 1991 to 2015. Adults aged 18–80 years old (n = 11,503) were included in the present analysis, for whom questionnaires and anthropometric data were collected during at least two waves. We constructed three-level mixed-effect linear regression models to estimate body mass index (BMI) in relation to wheat and rice intakes and performed three-level mixed-effect logistic regression models to assess the risk of overweight/obesity. Women showed significant BMI increases of 0.14 (95% CI: 0.04, 0.24) from a higher intake of wheat but not from a higher intake of rice when adjusted for all potential confounders. Comparing the highest quartiles of intake of wheat with non-consumers in men and women, odds ratios (ORs; 95% CI) of overweight/obesity were 1.45 (1.15, 1.85) and 1.26 (1.00, 1.60), respectively. In men, there was an inverse association with the risk of overweight/obesity in the comparison of the highest quartiles of intake of rice (OR: 0.73; 95% CI: 0.55, 0.96) and non-consumers when adjusted for all potential confounders. Higher intake of wheat was positively associated with the risk of overweight/obesity among Chinese adults. Further, there was an inverse association between rice intake with overweight/obesity in Chinese men but not in women.

Do gluten peptides stimulate weight gain in humans?

Observations from animal and in vitro laboratory research, and anecdotal evidence, have led to the suggestion that gluten consumption stimulates weight gain by the presence of peptides expressing opioid activity. Another proposed mechanism is that gluten peptides decrease resting energy expenditure resulting in a positive energy balance. In order to induce such effects in vivo, intact food peptides must be absorbed in sufficient quantities, remain intact in the blood for sufficient time to have long-lasting biological activity and bind to receptors involved in appetite, satiety and energy regulation. However, although peptides from food may pass from the intestine into the blood in extremely low quantities, they are generally rapidly degraded by plasma and vasculum-bound aminopeptidases, resulting in very short half-lives and loss of bioactivity. At present, gluten peptide sequences that influence regulators of energy metabolism have not been identified. Furthermore, data on the quantitative absorption of gluten peptides in the blood stream, their stability and lasting bioactivity are also lacking. Therefore, there is no evidence for proposed effects on driving appetite by the brain, nor on energy expenditure and weight gain. Furthermore, the level of overweight observed in various countries appears to be independent of the level of wheat consumption, and abundant observational evidence in humans shows that the levels of gluten consumption are neither related to daily calorie intake nor to BMI. This narrative review therefore discusses the proposed effects of gluten on bodyweight (BW) and putative biological mechanisms in the light of the current evidence.

Gluten-Free Diet Reduces Diet Quality and Increases Inflammatory Potential in Non-Celiac Healthy Women

AIM

Gluten-free diets (GFDs) have gained popularity in the general population. Nonetheless, controlled studies are necessary before decisions can be made to promote GFDs. We aimed to evaluate the effects of gluten intake on body weight, body composition, and resting energy expenditure and observe the changes in nutrient intake caused by GFDs.

METHODS

Twenty-three women were kept on a GFD for six weeks and received muffins with 20 g of gluten isolate (gluten period) or muffins without gluten (gluten-free period) in a crossover, single-blind, non-randomized trial. Gastrointestinal symptoms, food frequency questionnaires, body composition, and resting energy expenditure were assessed before the study (habitual or usual diet) and in the third and sixth weeks. Food intake was recorded daily for six weeks.

RESULTS

Gastrointestinal symptoms, resting energy expenditure, and body weight and composition were similar during the gluten period and gluten-free period. When the diet of the gluten-free period was compared with the habitual diet, we found an increase in the intake of fat and sodium and a reduction in the intake of fiber and vitamins B1, B6, B12, and folate. The nutrient imbalance caused by a GFD led to an increase in the dietary inflammatory index, thus suggesting that this type of diet has high inflammatory potential.

CONCLUSION

Gluten intake (20 g/day) did not alter body composition and resting energy expenditure in healthy women without caloric restriction in the diet for a short period (three weeks). However, a GFD led to changes in the composition of the diet, which worsened the quality of the diet and increased its inflammatory potential.

Physical exercise, obesity, inflammation and neutrophil extracellular traps (NETs): a review with bioinformatics analysis

Neutrophil extracellular traps (NETs) represent an innate organism defense mechanism characterized by neutrophil release of intracellular material to capture any aggressor agent. Elevated NETs release is associated with increased inflammatory response and related diseases, such as obesity. Chronic physical training is one of the main strategies to treat and prevent obesity. The relationship between physical training and NETs is still under study. The present review, followed by a bioinformatics analysis, demonstrates the meaningful connection between physical exercise, obesity, and NETs. The bioinformatics indicated TNF-α as a leading gene after the ontological analysis followed by positive-interleukin-6 regulation, chemokines, and inflammatory response regulation. The main results pointed to a relevant regulatory effect of physical training on NETs release, indicating physical exercise as a possible therapeutic target on modulating NETs and inflammation.

Gluten intake and metabolic health: conflicting findings from the UK Biobank

PURPOSE

The impact of gluten intake on metabolic health in subjects without celiac disease is unclear. The present study aimed to assess the association between gluten intake and body fat percentage (primary objective), as well as a broad set of metabolic health markers.

METHODS

Gluten intake was estimated in 39,927 participants of the UK Biobank who completed a dietary questionnaire for assessment of previous 24-h dietary intakes. Multiple linear regression analyses were performed between gluten intake and markers of metabolic health with Holm adjustment for multiple comparisons.

RESULTS

Median gluten intake was 9.7 g/day (male: 11.7 g/day; female: 8.2 g/day; p < 0.0001). In multiple linear regression analysis, association between gluten intake and percentage body fat was negative in males (β = - 0.028, p = 0.0020) and positive in females (β = 0.025, p = 0.0028). Furthermore, gluten intake was a negative predictor of total cholesterol (male: β = - 0.031, p = 0.0154; female: β = - 0.050, p < 0.0001), high-density lipoprotein cholesterol (male: β = - 0.052, p < 0.0001; female: β = - 0.068, p < 0.0001), and glomerular filtration rate (sexes combined: β = - 0.031, p < 0.0001) in both sexes. In females only, gluten intake was positively associated with waist circumference (β = 0.041, p < 0.0001), waist-to-height ratio (β = 0.040, p < 0.0001), as well as body mass index (β = 0.043, p < 0.0001), and negatively related to low-density lipoprotein cholesterol (β = - 0.035, p = 0.0011). A positive association between gluten intake and triglycerides was observed in males only (β = 0.043, p = 0.0001).

CONCLUSION

This study indicates that gluten intake is associated with markers of metabolic health. However, all associations are weak and not clinically meaningful. Limiting gluten intake is unlikely to provide metabolic health benefits for a population in total.

Gluten Intake and All-Cause and Cause-Specific Mortality: Prospective Findings from the UK Biobank

BACKGROUND

Gluten has been linked to adverse effects on metabolic and vascular health.

OBJECTIVES

The present study determines the association between dietary gluten intake and all-cause (primary objective), as well as cause-specific, mortality in people without celiac disease.

METHODS

Gluten intake was estimated in 159,265 participants of the UK Biobank which is a large multicenter, prospective cohort study initiated in 2006. Cox proportional hazard regression models were used and HRs were determined for all-cause and cause-specific mortality. All models were adjusted for confounders and multiple testing.

RESULTS

Median (IQR) age was 57 (49-62) y with 52.1% of participants being female. Gluten intake was 8.5 (5.1-12.4) g/d with significantly higher consumption in males [10.0 (6.3-14.1) g/d] than in females [7.2 (4.6-10.7) g/d] (P < 0.0001). During a median follow-up of 11.1 (10.6-11.9) y and 1.8 million person-years, 6259 deaths occurred. Gluten intake was not significantly associated with all-cause mortality after adjusting for confounders (HR: 1.00; 95% CI: 1.00, 1.01; P = 0.59). Dietary gluten was not significantly associated with cancer (HR: 1.00; 95% CI: 1.00, 1.01; raw P = 0.24) or noncancer (HR: 1.00; 95% CI: 0.99, 1.01; raw P = 0.56) mortality. However, gluten intake was positively associated with ischemic heart disease mortality (HR: 1.02; 95% CI: 1.01, 1.04; raw P = 0.003, Holm-adjusted P = 0.04).

CONCLUSIONS

Gluten intake is not significantly associated with all-cause and cancer mortality in adults without celiac disease. The findings support the hypothesis that limiting gluten intake is unlikely to provide significant overall survival benefits on a population level. The positive association between gluten intake and ischemic heart disease mortality requires further study.

Inconsistent effects of gluten on obesity: is there a role for the haptoglobin isoforms?

BACKGROUND AND AIMS

There is no clear evidence about the effects of gluten intake on obesity. It is known that gluten's effects on gut permeability are mediated by zonulin, a protein identified as pre-haptoglobin 2, a physiological regulator of the intestinal barrier. We investigated the obesogenic and inflammatory effects of gluten and its association with the haptoglobin genotype.

METHODS

This was a single blinded, crossover study, including 40 overweight or obesity women free of celiac disease. Participants adopted a gluten-free diet (GFD) for 8 weeks and consumed a gluten-free muffin (GF-M) or a gluten-containing muffin (GLU-M, 24 g gluten) for 4 weeks, switching muffin type during the subsequent 4 weeks. During a follow-up period of 4 weeks we evaluated the usual diet (UD). Food diaries were collected to estimate the macronutrient intake and dietary inflammatory index (DII®). Bodyweight and composition, resting energy expenditure (REE), and cytokines were assessed. Haptoglobin alleles (Hp1 and Hp2) were genotyped to characterize zonulin expression.

RESULTS

Energy and macronutrient intakes were similar during both periods, except for protein intake, which was higher during GLU-M. DII scores indicated a more inflammatory profile during the GF-M and GLU-M periods compared to UD. No differences were observed in body composition or REE between interventions when the Hp genotype was not considered. Nonetheless, those carrying the Hp2-2 genotype (overexpressing zonulin) presented lower REE and higher levels of IL6 and IL1beta only during gluten intake (GLU-M and UD) compared to age- and body mass index-matched Hp1-1 carrier. These results suggest an obesogenic and inflammatory action of gluten only in those overexpressing zonulin (Hp2-2).

CONCLUSION

These results highlight the importance of zonulin as the mediator of gluten obesogenic and inflammatory effects. Our data suggest that in the presence of gluten, zonulin release is associated with a reduction of REE and an increase of inflammatory markers that are not seen in zonulin low producers.

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.

Exit Gluten-Free and Enter Low FODMAPs: A Novel Dietary Strategy to Reduce Gastrointestinal Symptoms in Athletes

Exercise-associated physiological disturbances alter gastrointestinal function and integrity. These alterations may increase susceptibility to dietary triggers, namely gluten and a family of short-chain carbohydrates known as FODMAPs (fermentable oligo-, di-, monosaccharides and polyols). A recent surge in the popularity of gluten-free diets (GFDs) among athletes without celiac disease has been exacerbated by unsubstantiated commercial health claims and high-profile athletes citing this diet to be the secret to their success. Up to 41% of athletes at least partially adhere to a GFD diet, with the belief that gluten avoidance improves exercise performance and parameters influencing performance, particularly gastrointestinal symptoms (GIS). In contrast to these beliefs, seminal work investigating the effects of a GFD in athletes without celiac disease has demonstrated no beneficial effect of a GFD versus a gluten-containing diet on performance, gastrointestinal health, inflammation, or perceptual wellbeing. Interestingly, the subsequent reduction in FODMAPs concurrent with the elimination of gluten-containing grains may actually be the factors affecting GIS improvement, not gluten. Pre-existent in the gastrointestinal tract or ingested during exercise, the osmotic and gas-producing effects of variably absorbed FODMAPs may trigger or increase the magnitude of exercise-associated GIS. Research using FODMAP reduction to address gastrointestinal issues in clinically healthy athletes is emerging as a promising strategy to reduce exercise-associated GIS. Applied research and practitioners merging clinical and sports nutrition methods will be essential for the effective use of a low FODMAP approach to tackle the multifactorial nature of gastrointestinal disturbances in athletes.

The Janus Face of Cereals: Wheat-Derived Prebiotics Counteract the Detrimental Effect of Gluten on Metabolic Homeostasis in Mice Fed a High-Fat/High-Sucrose Diet

SCOPE

Cereals are important sources of carbohydrates, but also contain nutrients that could impact adiposity. The contribution of gluten to obesity and the effects of prebiotics-arabinoxylo-oligosaccharides (AXOS) and fructo-oligosaccharides (FOS)-that can be extracted from gluten-containing cereals are analyzed.

METHODS AND RESULTS

Mice are fed a control diet, Western diet (WD, consisting of high fat/high sucrose), or WD with 5% gluten. Prebiotics are tested in the WD with gluten. Gluten does not increase body weight and has a minor effect on ileal inflammation. Gluten decreases the expression of browning markers in the fat and increases the triglycerides synthesis in the muscle. AXOS decreases body weight and adiposity in fat pads muscle and liver. AXOS promotes gluten cleavage by the induction of prolyl endopeptidase that is translated into a reduction of gluten immunogenic peptides. Gluten has minor effects on cecal microbiota composition, whereas prebiotics increased Bifidobacterium, Butyricicoccus, Prevotella, and Parasutterella, which are all negatively correlated to the cecal content of gluten peptides.

CONCLUSION

While gluten may affect metabolic homeostasis, these effects are lessened when gluten is consumed along with cereal-derived fibers. If confirmed in humans, the authors bring new arguments to eat fiber-rich cereals to promote a healthy diet.

Gluten exacerbates atherosclerotic plaque formation in ApoE-/- mice with diet-induced obesity

OBJECTIVES

Atherosclerosis is an underlying cause of cardiovascular disease, and obesity is one of the risk factors for atherogenesis. Although a gluten-free diet (GFD) has gained popularity as a strategy for weight loss, little is known about the effects of gluten on obesity. We have previously shown a negative effect of gluten on obesity in mice. However, its effects on atherogenesis are still unknown. Therefore, the aim of this study was to determine the effects of gluten on atherosclerosis progression during obesity.

METHODS

Atherosclerosis-susceptible ApoE knockout mice were subjected to an obesogenic GFD or a diet with 4.5% gluten (GD) for 10 wk.

RESULTS

Results from the study found that food intake and lipid profile were similar between the groups. However, GD promoted an increase in weight gain, adiposity, and plasma glucose. Pro-inflammatory factors such as tumor necrosis factor, interleukin-6, chemokine ligand-2, and matrix metalloproteinase-2 and -9 also were increased in the adipose tissue of gluten-fed mice. This inflammatory profile was associated with reduced phosphorylation of Akt, and consequently with the intensification of insulin resistance. The GD-enhanced vascular inflammation contributed to the worsening of atherosclerosis in the aorta and aortic root. Inflammatory cells, such as monocyte/macrophage and natural killer cells, and oxidative stress markers, such as superoxide and nitrotyrosine, were increased in atherosclerotic lesions of the GD group. Furthermore, the lesions presented higher necrotic core and lower collagen content, characterizing the less stable plaques.

CONCLUSION

The gluten-containing high-fat diet was associated with a more severe proatherogenic profile than the gluten-free high-fat diet owing to increased inflammatory and oxidative status at atherosclerotic lesions in obese mice.

SOCS2 modulates adipose tissue inflammation and expansion in mice

INTRODUCTION

Obesity is usually triggered by a nutrient overload that favors adipocyte hypertrophy and increases the number of pro-inflammatory cells and mediators into adipose tissue. These mediators may be regulated by suppressors of cytokine signaling (SOCS), such as SOCS2, which is involved in the regulation of the inflammatory response of many diseases, but its role in obesity is not yet known. We aimed to investigate the role of SOCS2 in metabolic and inflammatory dysfunction induced by a high-refined carbohydrate-containing diet (HC).

MATERIAL AND METHODS

Male C57BL/6 wild type (WT) and SOCS2 deficient (SOCS2^-/-) mice were fed chow or an HC diet for 8 weeks.

RESULTS

In general, SOCS2 deficient mice, independent of the diet, showed higher adipose tissue mass compared with their WT counterparts that were associated with decreased lipogenesis rate in adipose tissue, lipolysis in adipocyte culture and energy expenditure. An anti-inflammatory profile was observed in adipose tissue of SOCS2^-/- by reduced secretion of cytokines, such as TNF and IL-6, and increased M2-like macrophages and regulatory T cells compared with WT mice. Also, SOCS2 deficiency reduced the differentiation/expansion of pro-inflammatory cells in the spleen but increased Th2 and Treg cells compared with their WT counterparts.

CONCLUSION

The SOCS2 protein is an important modulator of obesity that regulates the metabolic pathways related to adipocyte size. Additionally, SOCS2 is an inflammatory regulator that appears to be essential for controlling the release of cytokines and the differentiation/recruitment of cells into adipose tissue during the development of obesity.

Scientific evidence of diets for weight loss: Different macronutrient composition, intermittent fasting, and popular diets

New dietary strategies have been created to treat overweight and obesity and have become popular and widely adopted. Nonetheless, they are mainly based on personal impressions and reports published in books and magazines, rather than on scientific evidence. Animal models and human clinical trials have been employed to study changes in body composition and metabolic outcomes to determine the most effective diet. However, the studies present many limitations and should be carefully analyzed. The aim of this review was to discuss the scientific evidence of three categories of diets for weight loss. There is no one most effective diet to promote weight loss. In the short term, high-protein, low-carbohydrate diets and intermittent fasting are suggested to promote greater weight loss and could be adopted as a jumpstart. However, owing to adverse effects, caution is required. In the long term, current evidence indicates that different diets promoted similar weight loss and adherence to diets will predict their success. Finally, it is fundamental to adopt a diet that creates a negative energy balance and focuses on good food quality to promote health.

Aerobic training reduces immune cell recruitment and cytokine levels in adipose tissue in obese mice

Obesity is associated with an energy imbalance that results from excessive energy intake, low diet quality, and a sedentary lifestyle. The increased consumption of a high-refined carbohydrate (HC) diet is strongly related to higher adiposity and low-grade inflammation. Aerobic training is a well-known nonpharmacological intervention to treat obesity and metabolic disturbances. However, the mechanisms through which aerobic training ameliorates the low-grade inflammation induced by an HC diet should be further investigated. Our hypothesis herein was that aerobic training would decrease the recruitment of leukocytes in adipose tissue, thereby reducing the levels of cytokines and improving metabolism in mice fed an HC diet. Male Balb/c mice were assigned to the following groups: control diet/nontrained (C-NT), control diet/trained (C-T), high-refined carbohydrate diet/nontrained (HC-NT), and high-refined carbohydrate diet/trained (HC-T). Mice were submitted to moderate-intensity training sessions that consisted of running 60 min per day for 8 weeks. An intravital microscopy technique was performed in vivo in anesthetized mice to visualize the microvasculature of the adipose tissue. The HC diet induced obesity and increased the influx of immune cells into the adipose tissue. In contrast, HC-T mice presented a lower adiposity and adipocyte area. Furthermore, relative to HC-NT mice, HC-T mice showed increased resting energy expenditure, decreased recruitment of immune cells in the adipose tissue, reduced cytokine levels, and ameliorated hyperglycemia and fatty liver deposition. Collectively, our data enhance understanding about the anti-inflammatory effect of aerobic training and shed light on the adipose tissue-mediated mechanisms by which training promotes a healthier metabolic profile.

Nutritional composition of fad diets published on websites and blogs

ABSTRACT Objective To analyze quantitatively the diets available on blogs and websites. Methods The following 15 diets were analyzed: low-carb diet, gluten-free diet and intermittent fasting diet using the Virtual Nutri software program. The nutrients analyzed were as follows: carbohydrates, fibers, proteins, lipids, iodine, sodium, calcium, magnesium, iron, zinc, manganese, phosphorus, selenium, vitamins A, C, B6, B12, D, niacin, and folate. The nutrient values were compared with the Dietary Reference Intake recommendation for adults between the ages of 19-50 years. The macronutrient adequacy percentage was based on a 2000-kcal diet for a healthy life, as recommended by the World Health Organization. Results It was observed that most of the composition of macro and micronutrients was lower than the one established by the World Health Organization and the Dietary Reference Intake recommendation for adults between the ages of 19-50 years. Conclusion Long-term dieting can be a risk factor for several deficiency diseases and may endanger the health of individuals.

Possible Prevention of Diabetes with a Gluten-Free Diet

Gluten seems a potentially important determinant in type 1 diabetes (T1D) and type 2 diabetes (T2D). Intake of gluten, a major component of wheat, rye, and barley, affects the microbiota and increases the intestinal permeability. Moreover, studies have demonstrated that gluten peptides, after crossing the intestinal barrier, lead to a more inflammatory milieu. Gluten peptides enter the pancreas where they affect the morphology and might induce beta-cell stress by enhancing glucose- and palmitate-stimulated insulin secretion. Interestingly, animal studies and a human study have demonstrated that a gluten-free (GF) diet during pregnancy reduces the risk of T1D. Evidence regarding the role of a GF diet in T2D is less clear. Some studies have linked intake of a GF diet to reduced obesity and T2D and suggested a role in reducing leptin- and insulin-resistance and increasing beta-cell volume. The current knowledge indicates that gluten, among many environmental factors, may be an aetiopathogenic factors for development of T1D and T2D. However, human intervention trials are needed to confirm this and the proposed mechanisms.

A low-gluten diet induces changes in the intestinal microbiome of healthy Danish adults

Adherence to a low-gluten diet has become increasingly common in parts of the general population. However, the effects of reducing gluten-rich food items including wheat, barley and rye cereals in healthy adults are unclear. Here, we undertook a randomised, controlled, cross-over trial involving 60 middle-aged Danish adults without known disorders with two 8-week interventions comparing a low-gluten diet (2 g gluten per day) and a high-gluten diet (18 g gluten per day), separated by a washout period of at least six weeks with habitual diet (12 g gluten per day). We find that, in comparison with a high-gluten diet, a low-gluten diet induces moderate changes in the intestinal microbiome, reduces fasting and postprandial hydrogen exhalation, and leads to improvements in self-reported bloating. These observations suggest that most of the effects of a low-gluten diet in non-coeliac adults may be driven by qualitative changes in dietary fibres.

Gluten-free diets are increasingly common in the general population. Here, the authors report the results of a randomised cross-over trial involving middle-aged, healthy Danish adults, showing evidence that a low-gluten diet leads to gut microbiome changes, possibly due to variations in dietary fibres.

Effects of Gliadin consumption on the Intestinal Microbiota and Metabolic Homeostasis in Mice Fed a High-fat Diet

Dietary gluten causes severe disorders like celiac disease in gluten-intolerant humans. However, currently understanding of its impact in tolerant individuals is limited. Our objective was to test whether gliadin, one of the detrimental parts of gluten, would impact the metabolic effects of an obesogenic diet. Mice were fed either a defined high-fat diet (HFD) containing 4% gliadin (n = 20), or a gliadin-free, isocaloric HFD (n = 20) for 23 weeks. Combined analysis of several parameters including insulin resistance, histology of liver and adipose tissue, intestinal microbiota in three gut compartments, gut barrier function, gene expression, urinary metabolites and immune profiles in intestinal, lymphoid, liver and adipose tissues was performed. Mice fed the gliadin-containing HFD displayed higher glycated hemoglobin and higher insulin resistance as evaluated by the homeostasis model assessment, more hepatic lipid accumulation and smaller adipocytes than mice fed the gliadin-free HFD. This was accompanied by alterations in the composition and activity of the gut microbiota, gut barrier function, urine metabolome, and immune phenotypes within liver and adipose tissue. Our results reveal that gliadin disturbs the intestinal environment and affects metabolic homeostasis in obese mice, suggesting a detrimental effect of gluten intake in gluten-tolerant subjects consuming a high-fat diet.