Single-nucleotide polymorphisms and DNA methylation markers associated with central obesity and regulation of body weight

Epigenome Modulation Induced by Ketogenic Diets

Ketogenic diets (KD) are dietary strategies low in carbohydrates, normal in protein, and high, normal, or reduced in fat with or without (Very Low-Calories Ketogenic Diet, VLCKD) a reduced caloric intake. KDs have been shown to be useful in the treatment of obesity, metabolic diseases and related disorders, neurological diseases, and various pathological conditions such as cancer, nonalcoholic liver disease, and chronic pain. Several studies have investigated the intracellular metabolic pathways that contribute to the beneficial effects of these diets. Although epigenetic changes are among the most important determinants of an organism’s ability to adapt to environmental changes, data on the epigenetic changes associated with these dietary pathways are still limited. This review provides an overview of the major epigenetic changes associated with KDs.

Sex-Specific Associations between Gut Prevotellaceae and Host Genetics on Adiposity

The gut microbiome has been recognized as a tool for understanding adiposity accumulation and for providing personalized nutrition advice for the management of obesity and accompanying metabolic complications. The genetic background is also involved in human energy homeostasis. In order to increase the value of nutrigenetic dietary advice, the interplay between genetics and microbiota must be investigated. The purpose of the present study was to evaluate interactive associations between gut microbiota composition and 95 obesity-related single nucleotide polymorphisms (SNPs) searched in the literature. Oral mucosa and fecal samples from 360 normal weight, overweight and obese subjects were collected. Next generation genotyping of these 95 SNPs and fecal 16S rRNA sequencing were performed. A genetic risk score (GRS) was constructed with 10 SNPs statistically or marginally associated with body mass index (BMI). Several microbiome statistical analyses at family taxonomic level were applied (LEfSe, Canonical Correspondence Analysis, MetagenomeSeq and Random Forest), and Prevotellaceae family was found in all of them as one of the most important bacterial families associated with BMI and GRS. Thus, in this family it was further analyzed the interactive association between BMI and GRS with linear regression models. Interestingly, women with higher abundance of Prevotellaceae and higher GRS were more obese, compared to women with higher GRS and lower abundance of Prevotellaceae. These findings suggest relevant interrelationships between Prevotellaceae and the genetic background that may determine interindividual BMI differences in women, which opens the way to new precision nutrition-based treatments for obesity.

Methylome-Wide Association Study in Peripheral White Blood Cells Focusing on Central Obesity and Inflammation

Epigenetic signatures such as DNA methylation may be associated with specific obesity traits in different tissues. The onset and development of some obesity-related complications are often linked to visceral fat accumulation. The aim of this study was to explore DNA methylation levels in peripheral white blood cells to identify epigenetic methylation marks associated with waist circumference (WC). DNA methylation levels were assessed using Infinium Human Methylation 450K and MethylationEPIC beadchip (Illumina) to search for putative associations with WC values of 473 participants from the Methyl Epigenome Network Association (MENA) project. Statistical analysis and Ingenuity Pathway Analysis (IPA) were employed for assessing the relationship between methylation and WC. A total of 669 CpGs were statistically associated with WC (FDR < 0.05, slope ≥ |0.1|). From these CpGs, 375 CpGs evidenced a differential methylation pattern between females with WC ≤ 88 and > 88 cm, and 95 CpGs between males with WC ≤ 102 and > 102 cm. These differentially methylated CpGs are located in genes related to inflammation and obesity according to IPA. Receiver operating characteristic (ROC) curves of the top four significant differentially methylated CpGs separated by sex discriminated individuals with presence or absence of abdominal fat. ROC curves of all the CpGs from females and one CpG from males were validated in an independent sample (n = 161). These methylation results add further insights about the relationships between obesity, adiposity-associated comorbidities, and DNA methylation where inflammation processes may be involved.

Associations between olfactory pathway gene methylation marks, obesity features and dietary intakes

Background

Olfaction is an important sense influencing food preferences, appetite, and eating behaviors. This hypothesis-driven study aimed to assess associations between olfactory pathway gene methylation signatures, obesity features, and dietary intakes.

Methods

A nutriepigenomic analysis was conducted in 474 adults from the Methyl Epigenome Network Association (MENA) project. Anthropometric measurements, clinical data, and serum metabolic profiles of the study population were obtained from structured databases of the MENA cohorts. Habitual dietary intake was assessed using a validated semiquantitative food frequency questionnaire. DNA methylation was measured in circulating white blood cells by microarray (Infinium Human Methylation 450 K BeadChips). FDR values (p < 0.0001) were used to select those CpGs that showed the best correlation with body mass index (BMI) and waist circumference (WC). Pathway analyses involving the characterization of genes involved in the olfactory transduction system were performed using KEGG and pathDIP reference databases.

Results

Overall, 15 CpG sites at olfactory pathway genes were associated with BMI (p < 0.0001) and WC (p < 0.0001) after adjustments for potential confounding factors. Together, methylation levels at the15 CpG sites accounted for 22% and 20% of the variability in BMI and WC (r² = 0.219, p < 0.001, and r² = 0.204, p < 0.001, respectively). These genes encompassed olfactory receptors (OR4D2, OR51A7, OR2T34, and OR2Y1) and several downstream signaling molecules (SLC8A1, ANO2, PDE2A, CALML3, GNG7, CALML6, PRKG1, and CAMK2D), which significantly regulated odor detection and signal transduction processes within the complete olfactory cascade, as revealed by pathway enrichment analyses (p = 1.94 × 10^–10). Moreover, OR4D2 and OR2Y1 gene methylation patterns strongly correlated with daily intakes of total energy (p < 0.0001), carbohydrates (p < 0.0001), protein (p < 0.0001), and fat (p < 0.0001).

Conclusions

The results of this study suggest novel relationships between olfactory pathway gene methylation signatures, obesity indices, and dietary intakes.

Prediction of Blood Lipid Phenotypes Using Obesity-Related Genetic Polymorphisms and Lifestyle Data in Subjects with Excessive Body Weight

Background and Aim

Individual lipid phenotypes including circulating total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and triglycerides (TG) determinations are influenced by gene-environment interactions. The aim of this study was to predict blood lipid level (TC, LDL-c, HDL-c, and TG) variability using genetic and lifestyle data in subjects with excessive body weight-for-height.

Methods

This cross-sectional study enrolled 304 unrelated overweight/obese adults of self-reported European ancestry. A total of 95 single nucleotide polymorphisms (SNPs) related to obesity and weight loss were analyzed by a targeted next-generation sequencing system. Relevant genotypes of each SNP were coded as 0 (nonrisk) and 1 (risk). Four genetic risk scores (GRS) for each lipid phenotype were calculated by adding the risk genotypes. Information concerning lifestyle (diet, physical activity, alcohol drinking, and smoking) was obtained using validated questionnaires. Total body fat (TFAT) and visceral fat (VFAT) were determined by dual-energy X-ray absorptiometry.

Results

Overall, 45 obesity-related genetic variants were associated with some of the studied blood lipids. In addition to conventional factors (age, sex, dietary intakes, and alcohol consumption), the calculated GRS significantly contributed to explain their corresponding plasma lipid trait. Thus, HDL-c, TG, TC, and LDL-c serum concentrations were predicted by approximately 28% (optimism-corrected adj. R² = 0.28), 25% (optimism-corrected adj. R² = 0.25), 24% (optimism-corrected adj. R² = 0.24), and 21% (optimism-corrected adj. R²=0.21), respectively. Interestingly, GRS were the greatest contributors to TC (squared partial correlation (PC²) = 0.18) and LDL-c (PC² = 0.18) features. Likewise, VFAT and GRS had a higher impact on HDL-c (PC² = 0.09 and PC² = 0.06, respectively) and TG levels (PC² = 0.20 and PC² = 0.07, respectively) than the rest of variables.

Conclusions

Besides known lifestyle influences, some obesity-related genetic variants could help to predict blood lipid phenotypes.

An integrated transcriptomic and epigenomic analysis identifies CD44 gene as a potential biomarker for weight loss within an energy-restricted program

PURPOSE

The interindividual variable response to weight-loss treatments requires the search for new predictive biomarkers for improving the success of weight-loss programs. The aim of this study is to identify novel genes that distinguish individual responses to a weight-loss dietary treatment by using the integrative analysis of mRNA expression and DNA methylation arrays.

METHODS

Subjects from Metabolic Syndrome Reduction in Navarra (RESMENA) project were classified as low (LR) or high (HR) responders depending on their weight loss. Transcriptomic (n = 24) and epigenomic (n = 47) patterns were determined by array-based genome-wide technologies in human white blood cells at the baseline of the treatment period. CD44 expression was validated by qRT-PCR and methylation degree of CpGs of the gene was validated by MassARRAY^® EpiTYPER™ in a subsample of 47 subjects. CD44 protein levels were measured by ELISA in human plasma.

RESULTS

Different expression and DNA methylation profiles were identified in LR in comparison to HR. The integrative analysis of both array data identified four genes: CD44, ITPR1, MTSS1 and FBXW5 that were differently methylated and expressed between groups. CD44 showed higher expression and lower DNA methylation levels in LR than in HR. Although differences in CD44 protein levels between LR and HR were not statistically significant, a positive association was observed between CD44 mRNA expression and protein levels.

CONCLUSIONS

In summary, the combination of a genome-wide methylation and expression array dataset can be a useful strategy to identify novel genes that might be considered as predictors of the dietary response. CD44 gene transcription and methylation may be a possible candidate biomarker for weight-loss prediction.

Sex-specific epigenetic mediators between early life social disadvantage and adulthood BMI

AIM

The objective of this study was to identify potential epigenetic mediating pathways linking early life social disadvantage (ELSD) to adulthood BMI.

METHODS

Sex-specific epigenome-wide two-stage mediation analyses were conducted in blood and adipose tissue, and mediation estimates were obtained using cross-product mediation analysis. Pathway analyses were conducted using GREAT software (Bejerano Lab, CA, USA).

RESULTS

Candidate mediation CpG sites were identified in adipose tissue, but not blood, and were sex-specific. Significant mediation sites in females included CpG loci in genes: PKHG1, BCAR3, ADAM5P, PIEZO1, FGFRL1, FASN and DPP9, among others. Pathway analyses revealed evidence of enrichment for processes associated with TFG-β signaling and immunologic signatures. In males, significant mediation loci included sites in MAP3K5 and RPTOR, which have previously been associated with adipogenesis, inflammation and insulin resistance.

CONCLUSION

Our findings provide supportive evidence for the mediating role of epigenetic mechanisms in the effect of early life social disadvantage on adulthood BMI.

Endoplasmic reticulum stress epigenetics is related to adiposity, dyslipidemia, and insulin resistance

Unresolved ER stress is involved in the onset and progression of several obesity-related metabolic disorders, including dyslipidemia and insulin resistance. Different epigenetic modifications may regulate ER stress response and consequently disease risks. These epigenetic phenomena encompass DNA and histone methylation patterns in ER stress genes and downstream signaling molecules, as well as microRNA expression. Our results suggest potential associations of methylation signatures at ER regulatory genes in white blood cells with an abdominal/central obesity marker (waist circumference), dyslipidemia, and insulin resistance. Interestingly, most of these genes were implicated in ER stress, as revealed by pathway enrichment analysis. Together, these findings add knowledge into the current understanding of relationships between obesity and accompanying complications with epigenetics and ER stress. Here, we comment about the implication of ER stress in central/abdominal adiposity, dyslipidemia, and insulin resistance, with an emphasis on the role that epigenetics may play on these pathological processes.

Foodomics for human health: current status and perspectives

INTRODUCTION

In the post-genomic era, the opportunity to combine and integrate cutting-edge analytical platforms and data processing systems allowed the birth of foodomics, 'a discipline that studies the Food and Nutrition domains through the application of advanced omics technologies to improve consumer's well-being, health, and confidence'. Since then, this discipline has rapidly evolved and researchers are now facing the daunting tasks to meet consumers' needs in terms of food traceability, sustainability, quality, safety and integrity. Most importantly, today it is imperative to provide solid evidence of the mechanisms through which food can promote human health and well-being. Areas covered: In this review, the complex relationships connecting food, nutrition and human health will be discussed, with emphasis on the relapses for the development of functional foods and nutraceuticals, personalized nutrition approaches, and the study of the interplay among gut microbiota, diet and health/diseases. Expert commentary: Evidence has been provided supporting the role of various omic platforms in studying the health-promoting effects of food and customized dietary interventions. However, although associated to major analytical challenges, only the proper integration of multi-omics studies and the implementation of bioinformatics tools and databases will help translate findings from clinical practice into effective personalized treatment strategies.

INSIG2 rs7566605 single nucleotide variant and global DNA methylation index levels are associated with weight loss in a personalized weight reduction program

Single nucleotide polymorphisms associated with lipid metabolism and energy balance are implicated in the weight loss response caused by nutritional interventions. Diet-induced weight loss is also associated with differential global DNA methylation. DNA methylation has been proposed as a predictive biomarker for weight loss response. Personalized biomarkers for successful weight loss may inform clinical decisions when deciding between behavioral and surgical weight loss interventions. The aim of the present study was to investigate the association between global DNA methylation, genetic variants associated with energy balance and lipid metabolism, and weight loss following a non-surgical weight loss regimen. The present study included 105 obese participants that were enrolled in a personalized weight loss program based on their allelic composition of the following five energy balance and lipid metabolism-associated loci: Near insulin-induced gene 2 (INSIG2); melanocortin 4 receptor; adrenoceptor β2; apolipoprotein A5; and G-protein subunit β3. The present study investigated the association between a global DNA methylation index (GDMI), the allelic composition of the five energy balance and lipid metabolism-associated loci, and weight loss during a 12 month program, after controlling for age, sex and body mass index (BMI). The results demonstrated a significant association between the GDMI and near INSIG2 locus, after adjusting for BMI and weight loss, and significant trends were observed when stratifying by gender. In conclusion, a combination of genetic and epigenetic biomarkers may be used to design personalized weight loss interventions, enabling adherence and ensuring improved outcomes for obesity treatment programs. Precision weight loss programs designed based on molecular information may enable the creation of personalized interventions for patients, that use genomic biomarkers for treatment design and for treatment adherence monitoring, thus improving response to treatment.

Developmental Programming of Obesity and Liver Metabolism by Maternal Perinatal Nutrition Involves the Melanocortin System

Maternal obesity predisposes offspring to metabolic dysfunction and Non-Alcoholic Fatty Liver Disease (NAFLD). Melanocortin-4 receptor (Mc4r)-deficient mouse models exhibit obesity during adulthood. Here, we aim to determine the influence of the Mc4r gene on the liver of mice subjected to perinatal diet-induced obesity. Female mice heterozygous for Mc4r fed an obesogenic or a control diet for 5 weeks were mated with heterozygous males, with the same diet continued throughout pregnancy and lactation, generating four offspring groups: control wild type (C_wt), control knockout (C_KO), obese wild type (Ob_wt), and obese knockout (Ob_KO). At 21 days, offspring were genotyped, weaned onto a control diet, and sacrificed at 6 months old. Offspring phenotypic characteristics, plasma biochemical profile, liver histology, and hepatic gene expression were analyzed. Mc4r_ko offspring showed higher body, liver and adipose tissue weights respect to the wild type animals. Histological examination showed mild hepatic steatosis in offspring group C_KO. The expression of hepatic genes involved in regulating inflammation, fibrosis, and immune cell infiltration were upregulated by the absence of the Mc4r gene. These results demonstrate that maternal obesogenic feeding during the perinatal period programs offspring obesity development with involvement of the Mc4r system.

The contribution of genetics and environment to obesity

BACKGROUND

Obesity is a global health problem mainly attributed to lifestyle changes such as diet, low physical activity or socioeconomics factors. However, several evidences consistently showed that genetics contributes significantly to the weight-gain susceptibility.

SOURCES OF DATA

A systematic literature search of most relevant original, review and meta-analysis, restricted to English was conducted in PubMed, Web of Science and Google scholar up to May 2017 concerning the contribution of genetics and environmental factors to obesity.

AREAS OF AGREEMENT

Several evidences suggest that obesogenic environments contribute to the development of an obese phenotype. However, not every individual from the same population, despite sharing the same obesogenic environment, develop obesity.

AREAS OF CONTROVERSY

After more than 10 years of investigation on the genetics of obesity, the variants found associated with obesity represent only 3% of the estimated BMI-heritability, which is around 47-80%. Moreover, genetic factors per se were unable to explain the rapid spread of obesity prevalence.

GROWING POINTS

The integration of multi-omics data enables scientists having a better picture and to elucidate unknown pathways contributing to obesity.

AREAS TIMELY FOR DEVELOPING RESEARCH

New studies based on case-control or gene candidate approach will be important to identify new variants associated with obesity susceptibility and consequently unveiling its genetic architecture. This will lead to an improvement of our understanding about underlying mechanisms involved in development and origin of the actual obesity epidemic. The integration of several omics will also provide insights about the interplay between genes and environments contributing to the obese phenotype.

Nutriepigenomics and malnutrition

Epigenetics is defined as the modulation of gene expression without changes to the underlying DNA sequence. Epigenetic alterations, as a consequence of in utero malnutrition, may play a role in susceptibility to develop adulthood diseases and inheritance. However, the mechanistic link between epigenetic modifications and abnormalities in nutrition remains elusive. This review provides an update on the association of suboptimal nutritional environment and the high propensity to produce adult-onset chronic illnesses with a particular focus on modifications in genome functions that occur without alterations to the DNA sequence. We will mention the drivers of the phenotype and pattern of epigenetic markers set down during the reprogramming along with novel preventative and therapeutic strategies. New knowledge of epigenetic alterations is opening a gate toward personalized medicine.

Obesity: epigenetic aspects

Epigenetics, defined as inheritable and reversible phenomena that affect gene expression without altering the underlying base pair sequence has been shown to play an important role in the etiopathogenesis of obesity. Obesity is associated with extensive gene expression changes in tissues throughout the body. Epigenetics is emerging as perhaps the most important mechanism through which the lifestyle-choices we make can directly influence the genome. Considerable epidemiological, experimental and clinical data have been amassed showing that the risk of developing disease in later life is dependent on early life conditions, mainly operating within the normative range of developmental exposures. In addition to the 'maternal' interactions, there has been increasing interest in the epigenetic mechanisms through which 'paternal' influences on offspring development can be achieved. Nutrition, among many other environmental factors, is a key player that can induce epigenetic changes not only in the directly exposed organisms but also in subsequent generations through the transgenerational inheritance of epigenetic traits. Overall, significant progress has been made in the field of epigenetics and obesity and the first potential epigenetic markers for obesity that could be detected at birth have been identified. Fortunately, epigenetic phenomena are dynamic and rather quickly reversible with intensive lifestyle changes. This is a very promising and sustainable resolution to the obesity pandemic.

Histone macroH2A1.2 promotes metabolic health and leanness by inhibiting adipogenesis

Background

Obesity has tremendous impact on the health systems. Its epigenetic bases are unclear. MacroH2A1 is a variant of histone H2A, present in two alternatively exon-spliced isoforms macroH2A1.1 and macroH2A1.2, regulating cell plasticity and proliferation, during pluripotency and tumorigenesis. Their role in adipose tissue plasticity is unknown.

Results

Here, we show evidence that macroH2A1.1 protein levels in the visceral adipose tissue of obese humans positively correlate with BMI, while macroH2A1.2 is nearly absent. We thus introduced a constitutive GFP-tagged transgene for macroH2A1.2 in mice, and we characterized their metabolic health upon being fed a standard chow diet or a high fat diet. Despite unchanged food intake, these mice exhibit lower adipose mass and improved glucose metabolism both under a chow and an obesogenic diet. In the latter regimen, transgenic mice display smaller pancreatic islets and significantly less inflammation. MacroH2A1.2 overexpression in the mouse adipose tissue induced dramatic changes in the transcript levels of key adipogenic genes; genomic analyses comparing pre-adipocytes to mature adipocytes uncovered only minor changes in macroH2A1.2 genomic distribution upon adipogenic differentiation and suggested differential cooperation with transcription factors. MacroH2A1.2 overexpression markedly inhibited adipogenesis, while overexpression of macroH2A1.1 had opposite effects.

Conclusions

MacroH2A1.2 is an unprecedented chromatin component powerfully promoting metabolic health by modulating anti-adipogenic transcriptional networks in the differentiating adipose tissue. Strategies aiming at enhancing macroH2A1.2 expression might counteract excessive adiposity in humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s13072-016-0098-9) contains supplementary material, which is available to authorized users.

Epigenetics of obesity: beyond the genome sequence

PURPOSE OF REVIEW

After the study of the gene code as a trigger for obesity, epigenetic code has appeared as a novel tool in the diagnosis, prognosis and treatment of obesity, and its related comorbidities. This review summarizes the status of the epigenetic field associated with obesity, and the current epigenetic-based approaches for obesity treatment.

RECENT FINDINGS

Thanks to technical advances, novel and key obesity-associated polymorphisms have been described by genome-wide association studies, but there are limitations with their predictive power. Epigenetics is also studied for disease association, which involves decoding of the genome information, transcriptional status and later phenotypes. Obesity could be induced during adult life by feeding and other environmental factors, and there is a strong association between obesity features and specific epigenetic patterns. These patterns could be established during early life stages, and programme the risk of obesity and its comorbidities during adult life. Furthermore, recent studies have shown that DNA methylation profile could be applied as biomarkers of diet-induced weight loss treatment.

SUMMARY

High-throughput technologies, recently implemented for commercial genetic test panels, could soon lead to the creation of epigenetic test panels for obesity. Nonetheless, epigenetics is a modifiable risk factor, and different dietary patterns or environmental insights during distinct stages of life could lead to rewriting of the epigenetic profile.

Gene-Gene Interplay and Gene-Diet Interactions Involving the MTNR1B rs10830963 Variant with Body Weight Loss

BACKGROUND/AIMS

Investigation of the genetic makeup may facilitate the implementation of more personalized nutritional interventions. The aims were to examine whether the rs10830963 MTNR1B polymorphism affects weight loss in response to a hypocaloric diet and to find potential gene-gene interplays and gene-diet interactions.

METHODS

167 subjects enrolled in a personalized nutritional intervention for weight loss (3-6 weeks) were examined for anthropometric measurements, dietary habits and physical activity at baseline and at the first follow-up visit. Three polymorphisms, which have previously been associated with body weight regulation, rs10830963 (MTNR1B), rs9939609 (FTO) and rs17782313 (MC4R), were analyzed using the Luminex® 100/200™ System.

RESULTS

After adjusting for covariates, females with the rs10830963 CG/GG genotype showed lower weight loss than those with the CC genotype. In the total population, carriers of variant alleles of both FTO and MC4R showed a significant association with MTNR1B and weight loss outcome. Moreover, among women, higher total protein and animal protein intakes were associated with a lower weight loss in G allele carriers of the MTNR1B variant.

CONCLUSIONS

Our data evidenced that rs10830963 MTNR1B polymorphism could be associated with individual differences in weight loss induced by a hypocaloric diet. This association was influenced by FTO and MC4R loci and modified by baseline protein intake.

Future Perspectives of Personalized Weight Loss Interventions Based on Nutrigenetic, Epigenetic, and Metagenomic Data

As obesity has become a major global public health challenge, a large number of studies have analyzed different strategies aimed at inducing a negative energy balance and, consequently, body weight loss. However, most existing weight loss programs are generally unsuccessful, so several interventions have been carried out to identify physiologic and behavioral factors concerning this variability in order to implement more personalized treatment. Nowadays, an individualized approach is being proposed through so-called personalized nutrition, whereby not only the phenotype but also the genotype is used for customized nutrition treatment. Regarding body weight regulation, ∼70 polymorphisms have been identified in or near genes related to energy expenditure, appetite, adipogenesis, insulin resistance, and lipid metabolism. Although personalized nutrition refers mainly to genetic makeup, recent advances in the investigation of the epigenome and the microbiome open the door to implement more personalized recommendations for body weight management. In this context, recent studies have demonstrated the existence of several epigenetic markers that may modify gene expression and could be involved in the outcome of weight loss interventions. Moreover, different studies have shown that dietary interventions could affect the composition of gut microbiota and have an impact on body weight. The integration of nutrigenetic, epigenetic, and metagenomic data may lead to the design of more personalized dietary treatments to prevent chronic diseases and to optimize the individual's response to dietary interventions.

An Increase in Plasma Homovanillic Acid with Cocoa Extract Consumption Is Associated with the Alleviation of Depressive Symptoms in Overweight or Obese Adults on an Energy Restricted Diet in a Randomized Controlled Trial

BACKGROUND

Obesity has been associated with various health disorders, including psychological alterations. Cocoa consumption and weight management may produce a beneficial effect on these problems.

OBJECTIVE

The purpose of this study was to investigate the effect of cocoa extract supplementation as part of an energy-restricted diet on psychological status and peripheral dopaminergic activity in overweight or obese middle-aged subjects.

METHODS

In a 4-wk, double-blind, randomized, placebo-controlled parallel nutritional intervention, 22 men and 25 women [mean ± SD age: 57 ± 5 y; body mass index (kg/m2): 30.6 ± 2.3] were studied. After a 1-wk run-in period, volunteers consumed 15% energy-restricted diets; one-half of the volunteers were randomly assigned to receive ready-to-eat meals supplemented with 1.4 g cocoa extract/d (645 mg total polyphenols/d), whereas the rest of the volunteers received the same meals without cocoa supplementation. Plasma monoamines [dopamine, dopac, and homovanillic acid (HVA)], monoamine oxidase (MAO), and psychological status (anxiety and depressive symptoms) were analyzed in fasting participants at baseline and endpoint. Data were analyzed over time, and regression and correlation analyses were conducted to determine the relation between variables.

RESULTS

Depressive symptoms decreased in both groups after the intervention (control: -9.4%, P < 0.001; cocoa: -6.3%, P = 0.008), but anxiety symptoms did not. The increase in plasma HVA was 11.5% greater in the cocoa group than in the control group (P = 0.016), but plasma dopamine, dopac, and MAO changes did not differ between groups. A negative relation between changes in depressive symptoms and changes in plasma HVA was observed in the cocoa group (β = -0.39, P = 0.029). Moreover, the change in plasma dopamine was positively associated with the change in methyl-catechin-O-glucoronide in the cocoa-supplemented group (r = 0.69, P = 0.019).

CONCLUSION

The intake of cocoa extract by participants consuming a 15% energy-restricted diet contributed to an increase in plasma HVA concentrations. This change was associated with a reduction in depressive symptoms, suggesting a potential effect of cocoa extract intake on this relation. The present results are secondary analyses of a clinical trial that was registered at www.clinicaltrials.gov as NCT01596309.