Nutrigenomic approaches for obesity research

Melanin-concentrating hormone receptor 1 polymorphisms are associated with components of energy balance in the Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study

BACKGROUND

The melanin-concentrating hormone receptor 1 (MCHR1) is a G protein-coupled receptor that regulates energy balance and body composition in animal models. Inconsistent effects of MCHR1 polymorphisms on energy homeostasis in humans may partly be attributable to environmental factors.

OBJECTIVES

We examined the effect of 4 single nucleotide polymorphisms (rs133073, rs133074, rs9611386, and rs882111) in the MCHR1 gene on body composition as well as energy-related lifestyle factors (diet and physical activity). We also examined the effect of gene-lifestyle interactions on body composition.

DESIGN

A total of 1153 participants (248 men and 905 women) from the cross-sectional Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study were genotyped by using probe-based chemistry validated assays. Diet and physical activity were estimated by using validated frequency questionnaires, and body composition was assessed by using dual-energy X-ray absorptiometry.

RESULTS

Three polymorphisms (rs9611386, rs882111, and rs133073) were associated with differences in body-composition measurements (all P < 0.05). There was an interaction between rs9611386 and carbohydrate intake on total mass and waist circumference (both P ≤ 0.01). There was also an interaction between rs9611386 and body mass index categories (normal weight, overweight, and obese) on energy intakes (P = 0.02). A similar interaction was shown with rs882111 (P = 0.02). Interactions were also observed between each of these polymorphisms (rs9611386, rs882111, and rs133073) and physical activity score on body-composition measurements (all P < 0.05).

CONCLUSION

These findings suggest that polymorphisms in the MCHR1 gene are associated with differences in body composition and interact with physiologic and energy-related lifestyle factors.

Impact of obesity-related genes in Spanish population

Background

The objective was to investigate the association between BMI and single nucleotide polymorphisms previously identified of obesity-related genes in two Spanish populations. Forty SNPs in 23 obesity-related genes were evaluated in a rural population characterized by a high prevalence of obesity (869 subjects, mean age 46 yr, 62% women, 36% obese) and in an urban population (1425 subjects, mean age 54 yr, 50% women, 19% obese). Genotyping was assessed by using SNPlex and PLINK for the association analysis.

Results

Polymorphisms of the FTO were significantly associated with BMI, in the rural population (beta 0.87, p-value <0.001). None of the other SNPs showed significant association after Bonferroni correction in the two populations or in the pooled analysis. A weighted genetic risk score (wGRS) was constructed using the risk alleles of the Tag-SNPs with a positive Beta parameter in both populations. From the first to the fifth quintile of the score, the BMI increased 0.45 kg/m² in Hortega and 2.0 kg/m² in Pizarra. Overall, the obesity predictive value was low (less than 1%).

Conclusion

The risk associated with polymorphisms is low and the overall effect on BMI or obesity prediction is minimal. A weighted genetic risk score based on genes mainly acting through central nervous system mechanisms was associated with BMI but it yields minimal clinical prediction for the obesity risk in the general population.

Personalized medicine in women's obesity prevention and treatment: implications for research, policy and practice

The prevalence of obesity in America has reached epidemic proportions, and obesity among women is particularly concerning. Severe obesity (body mass index ≥35 kg m(-2) ) is more prevalent in women than men. Further, women have sex-specific risk factors that must be considered when developing preventive and therapeutic interventions. This review presents personalized medicine as a dynamic approach to obesity prevention, management and treatment for women. First, we review obesity as a complex health issue, with contributing sex-specific, demographic, psychosocial, behavioural, environmental, epigenetic and genetic/genomic risk factors. Second, we present personalized medicine as a rapidly advancing field of health care that seeks to quantify these complex risk factors to develop more targeted and effective strategies that can improve disease management and/or better minimize an individual's likelihood of developing obesity. Third, we discuss how personalized medicine can be applied in a clinical setting with current and emerging tools, including health risk assessments, personalized health plans, and strategies for increasing patient engagement. Finally, we discuss the need for additional research, training and policy that can enhance the practice of personalized medicine in women's obesity, including further advancements in the '-omics' sciences, physician training in personalized medicine, and additional development and standardization of innovative targeted therapies and clinical tools.

Evaluation of obesity clinic program in public community health centers in South Korea

The purpose of this study was to evaluate the obesity clinic program in the public community health centers in Korea in 2006-2007. The authors conducted a telephone questionnaire survey for participants to evaluate the outcome of the program. Samples were selected through convenient sampling: 30 persons per one public health center among 2560 participants. The level of improvement in obesity, regular exercise, and the effort for calorie reduction of the participants were analyzed. There were significant differences: The participants who were provided continuously the information of obesity clinic program reduced calories for weight loss (odds ratio [OR] = 2.37, 95% confidence interval [CI] = 1.34-4.19, P < .01), and showed concern about body weight (OR = 2.17, 95% CI = 1.07-4.41, P < 0.05). This study found that when the program information was provided continually and the participants were motivated, the community obesity program goals could be achieved.

Public health genomics: translating obesity genomics research into population health benefits

We examine how a public health genomics framework can be used to move genomic discoveries into clinical and public health practice for obesity prevention and treatment. There are four phases of translational research: T1: discovery to candidate health application; T2: health application to evidence-based practice guidelines; T3: practice guidelines to health practice; and T4: practice to population health impact. Types of multidisciplinary research and knowledge synthesis needed for each phase, as well as the importance of developing and disseminating evidence-based guidelines, are discussed. Because obesity genomics research is mostly in the discovery phase or in the very early phases of translation (T1), the authors present this framework to illustrate the range of translation activities needed to move genomic discoveries in obesity to actual applications that reduce the burden of obesity at the population level.

Nutrigenomic analysis of diet-gene interactions on functional supplements for weight management

Recent advances in molecular biology combined with the wealth of information generated by the Human Genome Project have fostered the emergence of nutrigenomics, a new discipline in the field of nutritional research. Nutrigenomics may provide the strategies for the development of safe and effective dietary interventions against the obesity epidemic. According to the World Health Organization, more than 60% of the global disease burden will be attributed to chronic disorders associated with obesity by 2020. Meanwhile in the US, the prevalence of obesity has doubled in adults and tripled in children during the past three decades. In this regard, a number of natural dietary supplements and micronutrients have been studied for their potential in weight management. Among these supplements, (-)-hydroxycitric acid (HCA), a natural extract isolated from the dried fruit rind of Garcinia cambogia, and the micronutrient niacin-bound chromium(III) (NBC) have been shown to be safe and efficacious for weight loss. Utilizing cDNA microarrays, we demonstrated for the first time that HCA-supplementation altered the expression of genes involved in lipolytic and adipogenic pathways in adipocytes from obese women and up-regulated the expression of serotonin receptor gene in the abdominal fat of rats. Similarly, we showed that NBC-supplementation up-regulated the expression of myogenic genes while suppressed the expression of genes that are highly expressed in brown adipose tissue in diabetic obese mice. The potential biological mechanisms underlying the observed beneficial effects of these supplements as elucidated by the state-of-the-art nutrigenomic technologies will be systematically discussed in this review.

Lifestyle factors associated with BMI in a Spanish graduate population: the SUN Study

OBJECTIVE

To study the association between BMI and lifestyle factors such as alcohol consumption, smoking habits, education level and marital status in a Spanish graduate population.

METHOD

Cross-sectional analysis of 8,706 participants (3,643 men and 5,063 women) from the Seguimiento Universidad de Navarra (SUN) Study, an ongoing dynamic cohort study in Spain. Data on body weight, height and sociodemographic characteristics, and lifestyle habits were collected with self-administered validated questionnaires.

RESULTS

Among older participants (above sex-specific median age), educational level was a factor independently associated with BMI. University graduates with a lower educational level (3-year college degree or 5-year university degree) had a significantly higher BMI than those with doctorate which requires, at least, 8 years of university studies in Spain. Mean BMI was significantly higher among past smokers than among never smokers. Alcohol consumption, marital and smoking status were associated with BMI only among men.

CONCLUSION

In a study whose members were all university graduates, several factors were independently associated with a higher BMI, such as less years of higher education, past smoking, marital status and higher alcohol consumption.