Macronutrients and the FTO gene expression in hypothalamus; a systematic review of experimental studies

The Impact of Haplotypes of the FTO Gene, Lifestyle, and Dietary Patterns on BMI and Metabolic Syndrome in Polish Young Adult Men

BACKGROUND

Variants in fat mass and the obesity-associated protein (FTO) gene have long been recognized as the most significant genetic predictors of body fat mass and obesity. Nevertheless, despite the overall evidence, there are conflicting reports regarding the correlation between different polymorphisms of the FTO gene and body mass index (BMI). Additionally, it is unclear whether FTO influences metabolic syndrome (MetS) through mechanisms other than BMI's impact. In this work, we aimed to analyze the impact of the following FTO polymorphisms on the BMI as well as MetS components in a population of young adult men.

METHODS

The patient group consisted of 279 Polish young adult men aged 28.92 (4.28) recruited for the MAGNETIC trial. The single-nucleotide polymorphisms (SNPs), located in the first intron of the FTO gene, were genotyped, and the results were used to identify "protective" and "risk" haplotypes and diplotypes based on the literature data. Laboratory, as well as anthropometric measurements regarding MetS, were performed. Measured MetS components included those used in the definition in accordance with the current guidelines. Data regarding dietary patterns were also collected, and principal components of the dietary patterns were identified.

RESULTS

No statistically significant correlations were identified between the analyzed FTO diplotypes and BMI (p = 0.53) or other MetS components (waist circumference p = 0.55; triglycerides p = 0.72; HDL cholesterol p = 0.33; blood glucose p = 0.20; systolic blood pressure p = 0.06; diastolic blood pressure p = 0.21). Stratification by the level of physical activity or adherence to the dietary patterns also did not result in any statistically significant result.

CONCLUSIONS

Some studies have shown that FTO SNPs such as rs1421085, rs1121980, rs8050136, rs9939609, and rs9930506 have an impact on the BMI or other MetS components; nevertheless, this was not replicated in this study of Polish young adult males.

The effect of FTO gene rs9939609 polymorphism on the association between colorectal cancer and different types of dietary fat intake: a case-control study

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers in the world. Some dietary factors such as fat intake have been identified as the risk factors for CRC. This study aimed to investigate the effect of fat mass and obesity-associated (FTO) gene rs9939609 polymorphism on the association between CRC and different types of dietary fats.

METHODS

This case-control study was performed on 135 CRC cases and 294 healthy controls in Tehran, Iran. Data on demographic factors, anthropometric measurements, physical activity, the intake of different types of dietary fats, and FTO gene rs9939609 polymorphism was collected from all participants. The association between cancer and dietary fat intake in individuals with different FTO genotypes was assessed using different models of logistic regression.

RESULTS

Oleic acid intake was higher in the case group compared to the control group in both people with TT (7.2±3.46 vs. 5.83±3.06 g/d, P=0.02) and AA/AT genotypes (8.7±6.23 vs. 5.57 ±3.2 g/d, P<0.001). Among carriers of AA/AT genotypes of FTO rs9939609 polymorphism, a positive association was found between CRC and higher intakes of oleic acid (OR=1.12, CI95% 1.03-1.21, P=0.01) and cholesterol (OR=1.01, CI95% 1.00-1.02; P=0.01) after adjusting for age, sex, physical activity, alcohol use, smoking, calorie intake, and body mass index.

CONCLUSION

Higher intakes of cholesterol and oleic acid were associated with a higher risk of CRC in FTO-risk allele carriers. The association of CRC and dietary fat may be influenced by the FTO genotype. Further longitudinal studies are warranted to confirm these findings.

The effects of FTO gene rs9939609 polymorphism on the association between colorectal cancer and dietary intake

Background

FTO gene is associated with obesity, dietary intake, and the risk of colorectal cancer (CRC). In this study, patients with colorectal cancer were assessed for the interactions between FTO gene polymorphisms and dietary intake.

Methods

This case-control study was carried out on 450 participants aged 35-70 years including 150 patients with colorectal cancer and 300 healthy controls. Blood samples were collected in order to extract DNA and genotyping of FTO gene for rs9939609 polymorphism. A validated 168-item food frequency questionnaire (FFQ) and the Nutritionist-IV software were used to assess dietary intake.

Results

In the participants with the TT genotype of FTO rs9939609 polymorphism, CRC risk was significantly associated with higher intake of dietary fat (OR:1.87 CI95%:1.76-1.99, p = 0.04), vitamin B3 (OR:1.20 CI95%:1.08-1.65, p = 0.04), and vitamin C (OR:1.06 CI95%:1.03-1.15, p = 0.04) and lower intake of β-carotene (OR:0.98 CI95%:0.97-0.99, p = 0.03), vitamin E (OR:0.77 CI95%:0.62-0.95, p = 0.02), vitamin B1 (OR:0.15 CI95%:0.04-0.50, p < 0.01), and biotin (OR:0.72 CI95%:0.0.57-0.92, p = 0.01). No significant association was found between CRC and dietary intake in carriers of AA/AT genotypes after adjustments for the confounders.

Conclusion

CRC risk may be decreased by β-carotene, vitamins E, B1, and biotin only in those without the risk allele of the FTO gene. The association of CRC and diet may be influenced by FTO genotype. Further studies are warranted.

Interactions dietary components with expression level of breast cancer-related genes

Background

Dietary components can influence the effects of genetic background in breast cancer (BC). This review study aimed to investigate the effect of dietary components on the expression level of BC-related genes.

Methods

In this narrative review, Embase, PubMed, PsycInfo, and the Cochrane databases were used to collect the related papers with interactions of BC, genetics, and dietary intake. Appropriate keywords such as BC, gene expression, mutation, nutrient, and diet (alone and together) were applied for data collection.

Results

The association of BC with some genes including the BC1 gene (BRCA1), the human epidermal growth factor receptor 2 (HER2), and the fat mass and obesity-associated (FTO) gene can be affected by dietary components. Moderate B12 supplementation may be protective against BC in people with the inherited mutation of BRCA. The olive oil may have a protective effect against BC through several mechanisms such as suppressing HER-2 expression. Furthermore, high glycemic index foods may increase the risk of BC by the activation of the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway and the up-regulation of FTO gene expression.

Conclusion

There are interactions between BC, BC-related genes, and dietary intake. Dietary components such as macronutrients, micronutrients, and phytochemicals may regulate the expression level of BC-related genes. Further longitudinal studies are needed to confirm the associations between BC-related genes and diet and to discover the underlying mechanisms.

Unraveling the Complex Interactions between the Fat Mass and Obesity-Associated (FTO) Gene, Lifestyle, and Cancer

Carcinogenesis is a complicated process and originates from genetic, epigenetic, and environmental factors. Recent studies have reported a potential critical role for the fat mass and obesity-associated (FTO) gene in carcinogenesis through different signaling pathways such as mRNA N6-methyladenosine (m6A) demethylation. The most common internal modification in mammalian mRNA is the m6A RNA methylation that has significant biological functioning through regulation of cancer-related cellular processes. Some environmental factors, like physical activity and dietary intake, may influence signaling pathways engaged in carcinogenesis, through regulating FTO gene expression. In addition, people with FTO gene polymorphisms may be differently influenced by cancer risk factors, for example, FTO risk allele carriers may need a higher intake of nutrients to prevent cancer than others. In order to obtain a deeper viewpoint of the FTO, lifestyle, and cancer-related pathway interactions, this review aims to discuss upstream and downstream pathways associated with the FTO gene and cancer. The present study discusses the possible mechanisms of interaction of the FTO gene with various cancers and provides a comprehensive picture of the lifestyle factors affecting the FTO gene as well as the possible downstream pathways that lead to the effect of the FTO gene on cancer.

Differential Effect of Fat Intake on Blood Pressure in Healthy Japanese Women with and without the Variant of Fat Mass and Obesity-Associated Gene

A high-fat diet is believed to be a risk factor for hypertension through inducing obesity. It has been reported that variants of the fat mass and obesity-associated (FTO) and beta-3 adrenergic receptor (B3AR) genes are associated with obesity and blood pressure. The purpose of this study was to investigate the effect of dietary fat on blood pressure with or without the variant of the FTO and B3AR genes. A total of 227 healthy Japanese women aged 18 to 64 years were recruited for measurement of nutrient intake and blood pressure. The single nucleotide polymorphism rs9939609 of the FTO gene and rs4994 of the B3AR gene were genotyped. Spearman's rank correlation coefficient was applied to investigate the relationship between fat intake and blood pressure. A hierarchical multiple regression analysis was performed to determine whether the genotype interacts with fat intake to affect blood pressure. No significant correlations were found between fat intake and either systolic or diastolic blood pressure. A significant negative correlation was found between fat intake and both blood pressures in the FTO-gene-variant group, but not in the normal-FTO-gene group. In hierarchical multiple regression analysis, the interaction of fat intake and the gene variant showed significance, and the change in coefficient of determination (R ²) was significantly increased with increases of the interaction variable. These results indicate that the effect of fat intake on blood pressure may be modified by the variant of the FTO gene such that a high-fat diet intake may be associated with a decrease of systolic and diastolic blood pressure in healthy Japanese women with the FTO variant. Our results did not support the hypothesis that a high-fat diet increases blood pressure.

Association of calorie and carbohydrate intake with tumour grade in early diagnosis of breast cancer: a case-control study

BACKGROUND

This study aimed to investigate the association of calorie and carbohydrate intake with tumour grade in early detection of breast cancer (BC) in Iranian women.

MATERIALS AND METHODS

This case-control study carried out on 62 women with high grade BC and 93 women with low grade BC. Information about confounding variables was collected through a questionnaire. Dietary intake of calorie and macronutrients was assessed by a valid 122-item semi-quantitative food frequency questionnaire.

RESULTS

Individuals with high grade BC had significantly lower calorie (0.16, 0.04-0.61) and higher carbohydrate intake (4.02; 1.28-12.63) compared with those with low grade BC after controlling for age. This correlation remained significant after adjusting for confounding factors.

CONCLUSION

Our results showed that lower intakes of calorie and higher carbohydrate are directly related to the high grade of tumour at the early detection of people with BC after modifying a wide range of confounding factors.

The Advent of Nutrigenomics: A Narrative Review with an Emphasis on Psychological Disorders

A new research field is emerging that combines nutrition and genetics at the molecular level, namely nutrigenomics. Several aspects of nutrigenomics are examined in this review, with a particular focus on psychological disorders. The origin of this field in the 20th century and its modern developments have been investigated. Various studies have reported the impact of genetic factors and diet on various chronic disorders, elucidating how the deficiency of several macronutrients results in significant ailments, including diabetes, cancer, cardiovascular disorders, and others. Furthermore, the application of nutrigenomics to diet and its impact on the global disease rate and quality of life have been discussed. The relationship between diet and gene expression can facilitate the classification of diet-gene interactions and the diagnosis of polymorphisms and anomalies. Numerous databases and research tools for the study of nutrigenomics are essential to the medical application of this field. The nutrition-gene interrelationships can be utilized to study brain development, impairment, and diseases, which could be a significant medical breakthrough. It has also been observed that psychological conditions are exacerbated by the interaction between gut microbes and the prevalence of malnutrition. This article focuses on the impact of nutrition on genes involved in various psychological disorders and the potential application of nutrigenomics as a revolutionary treatment method.

Sesame Oil Ameliorates Alanine Aminotransferase, Aspartate Aminotransferase, and Fatty Liver Grade in Women with Nonalcoholic Fatty Liver Disease Undergoing Low-Calorie Diet: A Randomized Double-Blind Controlled Trial

Background

The type and amount of dietary fats play an important role in fat accumulation in the liver. Sesame oil (SO) is a good source of monounsaturated acids (MUFAs) and polyunsaturated fatty acids (PUFAs).

Objective

This trial aimed at examining the effect of SO consumption on the levels of liver enzymes and the severity of fatty liver in women with nonalcoholic fatty liver disease (NAFLD) undergoing a weight loss diet.

Methods

This randomized, double-blind, controlled trial was carried out on 60 women with NAFLD. Subjects were randomly assigned to the SO group (n = 30) and sunflower oil (SFO) group (n = 30), each person consuming 30 grams of oil per day for 12 weeks. All the participants received a hypocaloric diet (-500 kcal/day) during the study. Fatty liver grade and liver enzymes were assessed at pre- and postintervention phases.

Results

53 patients completed the study. Significant reductions in body weight, body mass index (BMI), waist circumference (WC), and fatty liver grade were observed in both groups (P < 0.05). Following SO, significant decreases in serum aspartate and alanine aminotransferases (AST and ALT) were observed. After adjusting for confounders, ALT, AST, and fatty liver grade of the SO group were significantly reduced compared to the SFO group (P < 0.05). However, the changes in serum alkaline phosphatase (ALP) were not significant (P > 0.05).

Conclusions

The desired effects of weight loss were reinforced by the consumption of SO through improving fatty liver severity and serum ALT and AST levels in NAFLD patients. Moreover, low-calorie diets may lead to favorable outcomes for NAFLD patients through mitigation of obesity and fatty liver grade.

The Association of Fat-Mass-and Obesity-Associated Gene Polymorphism (rs9939609) With Colorectal Cancer: A Case-Control Study

Background and Aim

The association between the rs9939609 polymorphism of fat mass and obesity-associated gene (FTO) and risk of colorectal cancer is controversial. This study aims to evaluate the relationship between FTO rs9939609 polymorphism and colorectal cancer (CRC) in Iranian people.

Methods

A case-control study was conducted on 125 patients with CRC and 250 healthy subjects in Tehran, Iran. Demographic data and blood samples were collected from all participants. Genotyping of rs9939609 polymorphism was performed by the tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method.

Results

The occurrence of AA genotype of FTO rs9939609 polymorphism in the colorectal cancer patients was significantly higher compared to that of healthy subjects (16.4 vs. 2.9%, respectively, P=0.02). The association between the frequency of risk allele of the FTO polymorphism and CRC (B=1.67, P=0.042) remained significant after adjustment for age. Further adjustment for gender (model 2) and marital status (model 3) did not change this result (B=1.67, P= 0.042 and B=1.67, P=0.043, respectively). The results remained significant after additional adjustment for ethnicity (B=1.57, P= 0.047).

Conclusion

We found a positive association between the A allele of the rs9939609 polymorphism and CRC. Future studies are required to identify the underlying mechanisms.

Methylation and Expression of FTO and PLAG1 Genes in Childhood Obesity: Insight into Anthropometric Parameters and Glucose-Lipid Metabolism

The occurrence of childhood obesity is influenced by both genetic and epigenetic factors. FTO (FTO alpha-ketoglutarate dependent dioxygenase) is a gene of well-established connection with adiposity, while a protooncogene PLAG1 (PLAG1 zinc finger) has been only recently linked to this condition. We performed a cross-sectional study on a cohort of 16 obese (aged 6.6-17.7) and 10 healthy (aged 11.4-16.9) children. The aim was to evaluate the relationship between methylation and expression of the aforementioned genes and the presence of obesity as well as alterations in anthropometric measurements (including waist circumference (WC), body fat (BF_kg) and body fat percent (BF_%)), metabolic parameters (lipid profile, blood glucose and insulin levels, presence of insulin resistance) and blood pressure. Expression and methylation were measured in peripheral blood mononuclear cells using a microarray technique and a method based on restriction enzymes, respectively. Multiple regression models were constructed to adjust for the possible influence of age and sex on the investigated associations. We showed significantly increased expression of the FTO gene in obese children and in patients with documented insulin resistance. Higher FTO expression was also associated with an increase in WC, BF_kg, and BF_% as well as higher fasting concentration of free fatty acids (FFA). FTO methylation correlated positively with WC and BF_kg. Increase in PLAG1 expression was associated with higher BF%. Our results indicate that the FTO gene is likely to play an important role in the development of childhood adiposity together with coexisting impairment of glucose-lipid metabolism.

Associations between FTO rs9939609 polymorphism, serum vitamin D, mental health, and eating behaviors in overweight adults

Background: Despite the significant role of the Fat Mass and Obesity-Associated (FTO) gene in obesity, the underlying mechanisms are not fully elucidated. Besides, vitamin D deficiency and obesity are mostly seen together, and it can be hypothesized that this nutrient may have an impact in the role of FTO genotype in adiposity.Objective: Thus, this study aimed to investigate the association of FTO rs9939609 gene polymorphism with eating behaviors, eating disorders, and general mental health in overweight adults, considering their vitamin D intake as a mediate confounding factor.Methods: This cross-sectional study was carried out on 197 overweight adults in Shiraz, Iran. Genotyping was performed through amplification refractory mutation system polymerase chain reaction (ARMS PCR). Mental health, vitamin D intake, eating behaviors and disorders were assessed by the validated questionnaires.Results: The risk allele of the FTO rs9939609 polymorphism (A) was significantly associated with a higher risk of eating behavior and mental health disorders (all P < 0.05). After considering vitamin D intake, the AA genotype carriers had significantly higher risks for poorer eating behavior (P = 0.002), mental health (P = 0.007), and general mental health (P = 0.039) compared with the TT carriers if they had insufficient vitamin D intake.Conclusion: In conclusion, these results indicated that the A-allele of the FTO rs9939609 polymorphism may be associated with poorer eating behaviors, mental health, and higher risk of eating disorders. It was also identified that the effect of FTO rs9939609 A risk allele on eating behavior and mental health may be limited to people with insufficient vitamin D intake.

Up-regulation of FTO gene expression was associated with increase in skeletal muscle mass in overweight male adolescents

INTRODUCTION

The modifying effect of FTO gene expression level on change in body mass index and body composition has not been studied before. This study aimed to investigate the association between change in the expression level of the FTO gene and changes in anthropometric measurements in obese and overweight adolescent boys.

MATERIAL AND METHODS

Eighty-four boys aged 12 to 16 years participated in this longitudinal study. A Bio Impedance Analyzer (BIA) was used to estimate percentage of body fat (%BF) and percentage of skeletal muscle (%SM). The FTO gene expression level in peripheral blood mononuclear cells was assessed using quantitative real-time PCR (qPCR). All measurements were performed at baseline and after 18 weeks.

RESULTS

After 18 weeks, mean weight was reduced by 2.39 kg, body mass index by 0.09 kg/m², %BF by 0.82% and %SM increased by 0.44%. Moreover, the level of FTO gene expression increased 0.42-fold higher than baseline. The change in expression level of the FTO gene was positively associated with change in %SM (β = 0.31, p = 0.02).

CONCLUSIONS

FTO gene expression change was associated with change in %SM in male adolescents. Future studies are required to assess the interactions between FTO gene expression in different tissues and body composition.

The possible mechanisms of the effects of IRX3 gene on body weight: an overview

Introduction

Recent studies reported that FTO exert its effects on body weight through change the expression IRX3. The aim of this study was investigation of the possible mechanisms of the effects of IRX3 gene on obesity.

Material and methods

The present review was carried out using keywords such as polymorphism and/or obesity and/or BMI and/or IRX3 gene and/or Iroquois homeobox protein 3. Databases including PubMed, Science Direct, web of sciences, Scopus, and Cochran databases were used to collect all related articles published from 2000 to 2019.

Results

Based on this review, there are some evidences on the association between the IRX3 polymorphisms and the IRX3 expression level with body weight. In some studies, the up-regulation of IRX3 expression was related to increased body weight, while in some other studies down-regulation of IRX3 expression was related to obesity.

Conclusions

This review investigated the probable mechanisms of the effects of the IRX3 gene on obesity. Studies in this are limited and reported contradictory results. Further studies are required to evaluate the role of IRX3 gene in the associations between genes, diet, and obesity.

The Role of FTO Genotype in the Association Between FTO Gene Expression and Anthropometric Measures in Obese and Overweight Adolescent Boys

The role of FTO genotype in the effect of FTO gene expression level on change in body mass index and body composition has not been studied. This study aimed to investigate the role of FTO genotype in the association between change in the expression level of the FTO gene with changes in anthropometric measurements in obese and overweight adolescent boys. Eighty-four boys aged 12 to 16 years participated in this longitudinal study. A bioimpedance analyzer (BIA) was used to estimate percentage of body fat (%body fat) and percentage of skeletal muscle (%skeletal muscle). The FTO gene expression level in peripheral blood mononuclear cells (PBMCs) was assessed using quantitative Real Time PCR (qPCR). The DNA samples were genotyped for the FTO gene polymorphisms by DNA sequencing. All measurements were performed at baseline and after intervention. A significant association was observed between the level of gene expression and %skeletal muscle. The gene expression fold change was significantly associated with change in %skeletal muscle in AA or AG genotype carriers (β = 0.34, p = .02). No significant association was detected between the change in FTO gene expression with change in anthropometric indices in GG genotype carriers. In conclusion, the association between FTO gene expression and body composition can be influenced by FTO genotype. Future studies are required to assess the interactions between FTO genotype, FTO gene expression in different tissues, and body composition.

Effects of gene polymorphisms of metabolic enzymes on the association between red and processed meat consumption and the development of colon cancer; a literature review

The role of environmental factors and genetic susceptibility in the development of colon cancer (CC) has been already proven, but the role of gene polymorphisms in modifying the risk of environmental factors such as nutritional factors is still unknown. This study aimed to investigate the effect of polymorphisms of involved genes in the association between red meat consumption and the development of CC. The present review was carried out using keywords such as polymorphism and/or protein and/or red meat and/or processed meat and/or colon cancer. PubMed and Science Direct databases were used to collect all related articles published from 2001 to 2017. The presence of SNP in the coding genes of proteins involved in metabolism of nutrients could play significant roles in the extent of the effects of nutrition in the development of CC. The effect of dietary proteins greatly depends on the polymorphisms in the metabolising genes of these substances. Gene polymorphisms may have a role in colorectal cancer risk, especially in people with high meat intake, and this leads to a difference in the effects of meat consumption in different individuals. To conclude, dietary recommendations for the prevention and control of CC should be modified based on the genotype of different individuals. Increasing our knowledge on this field of nutritional genomics can lead to personalised preventive and therapeutic recommendations for CC patients.

A complete linkage disequilibrium in a haplotype of three SNPs in Fat Mass and Obesity associated (FTO) gene was strongly associated with anthropometric indices after controlling for calorie intake and physical activity

Background

The underlying mechanism of the effect of FTO genotype on body mass index (BMI) and body composition is unknown. The objective of the study was to investigate the association of FTO gene polymorphisms with anthropometric indices in adolescent boys after adjustments for dietary intake and physical activity.

Methods

In this school-based study, we enrolled 123 male adolescents without extra weight and 110 male adolescents with body mass index (BMI) higher than + 1 Z-score. The DNA samples were genotyped for the FTO gene polymorphisms by DNA Sequencing. BMI and body composition were assessed using bioelectrical impedance analyzer scale. Association of the FTO polymorphisms with Weight, height, BMI, body fat percent and skeletal muscle percent were investigated. Data on potential confounders (calorie intake and physical activity) were collected through the use of pre-tested questionnaires.

Results

Adolescents with higher BMI and body fat percent and lower skeletal muscle percent were more likely to have a newly found haplotype of rs9930506, rs9930501 & rs9932754 (GGT) in the first intron of the FTO with complete linkage disequilibrium (LD) compared with those with the lower BMI (6.15;2.28–16.63), body fat percent (9.54;0.92–47.44) and higher skeletal muscle percent (9.26;1.85–46.38). This association was not changed after controlling for age. Additional adjustments for calorie intake and physical activity did not alter the association.

Conclusions

A haplotype in the first intron of the FTO gene had a strong association with obesity indices in adolescent boys after adjustments for calorie intake and physical activity. It’s suggested that the FTO genotype exert its effects on adolescents’ anthropometric indices as haplotype and through mechanisms other than changes in calorie intake and expenditure.

Trial registration

This paper reports the first phase of a comprehensive interventional study (Interactions of Genetics, lifestyle and anthropometrics study or IGLA study) and is retrospectively registered in the Iranian Registry of Clinical Trials as IRCT2016020925699N2. Date registered: April 24, 2016. (http://www.irct.ir/searchresult.php?id=25699&number=2).

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0664-z) contains supplementary material, which is available to authorized users.

A haplotype of three SNPs in FTO had a strong association with body composition and BMI in Iranian male adolescents

Background

Single-nucleotide polymorphisms (SNPs), which are located in the first intron of the FTO gene, are reported to be associated with body weight and the body mass index (BMI). However, their effects on anthropometric measurements in adolescents are poorly understood.

Objective

This study aimed to investigate the association of three adjacent polymorphisms (rs9930506, rs9930501, & rs9932754) in the FTO gene with anthropometric indices in Iranian adolescent males.

Design

The participants comprised a total of 237 adolescent males who were recruited randomly from two high schools in Tehran, Iran. The DNA samples were genotyped for the FTO gene polymorphisms by DNA sequencing. BMI, body fat percentage (BF%), and body muscle percentage (BM%) were determined using a validated bioelectrical impedance analysis scale. The association of the FTO polymorphisms with weight, height, BMI, BF%, and BM% was investigated.

Results

A haplotype of rs9930506, rs9930501, and rs9932754 (GGT) in the first intron of the FTO with complete linkage disequilibrium (LD) was found to be significantly associated with higher weight (OR = 1.32), BMI (OR = 5.36) and BF% (OR = 1.46), and lower BM% (OR = 3.59) (all P<0.001). None of the students with GGC genotypes were underweight, while all of the students with AAT genotypes had high muscle mass.

Conclusions

A haplotype in the first intron of the FTO gene had a strong association with obesity indices in Iranian adolescent males. The FTO gene polymorphisms might have greater effects on anthropometric indices than what was previously imagined. Moreover, we suggested that the FTO gene exerted their effects on anthropometric measurements through haplotypes (and not single SNPs).

The Effects of Extra Virgin Olive Oil on Alanine Aminotransferase, Aspartate Aminotransferase, and Ultrasonographic Indices of Hepatic Steatosis in Nonalcoholic Fatty Liver Disease Patients Undergoing Low Calorie Diet

BACKGROUND

Coronary artery disease is the most common cause of death in the patients with nonalcoholic fatty liver disease (NAFLD). Studies have shown that there is a strong relation between the increase in the aminotransferase levels and fat accumulation in the liver with cardiovascular complications, independent of all aspects of the metabolic syndrome. This study aimed to examine the effect of virgin olive oil on alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the severity of steatosis in the NAFLD patients undergoing a weight-loss diet.

METHODS

This clinical trial was carried out on 50 patients with nonalcoholic fatty liver (mean age of 45.91 ± 9.61 years, mean BMI of 29.7 ± 0.58 Kg/m²) and the subjects were randomly assigned to the olive oil group (receiving the equivalent of 20% of their total daily energy requirement from olive oil) or the control group (with normal consumption of oil) for 12 weeks. All the patients received a hypocaloric diet during the study. At the beginning and the end of the study, the serum levels of ALT and AST and liver steatosis were measured.

FINDINGS

A significant decrease in the level of ALT enzymes was observed in the control group at the end of the study (P = 0.004). In the olive oil group, both enzymes decreased compared to baseline measurements (P < 0.01). There were significant differences in the ALT and AST levels between the two groups (P < 0.02). The severity of liver steatosis did not change significantly during the study.

CONCLUSION

The consumption of a low calorie diet enriched with olive oil, along with slight weight reduction, reinforces the desired effects of weight loss in improving the levels of the hepatic enzymes.

FTO Gene Affects Obesity and Breast Cancer Through Similar Mechanisms: A New Insight into the Molecular Therapeutic Targets

OBJECTIVES

This review focused on the possible mediatory role of the FTO in the association between obesity and breast cancer.

METHOD

All articles published in English from June 1990 to January 2017 were studied. The search terms used were FTO gene, FTO polymorphism, breast cancer, and obesity. Inclusion criteria consisted of assessment of the relationship between FTO polymorphisms and/or FTO expression level with obesity and/or breast cancer as a primary outcome.

RESULTS

The FTO gene may have a role in the cellular sensing of macronutrients. Over expression of the FTO gene increases the levels of mammalian target of rapamycin (mTOR) signaling that is a key regulator of cell growth. Moreover, some SNPs in intron locations of the FTO gene exert their effects on body mass index, body composition and breast cancer risk through change of the homeobox transcription factor iriquois 3 (IRX3) gene expression level.

CONCLUSION

The FTO gene may has a critical role in obesity and breast cancer. Similar molecular mechanisms may play a role in the development of breast cancer and obesity. If this result is correct then, it will be interesting to examine the FTO gene as a molecular therapeutics target.

Review of studies on the fat mass and obesity-associated (FTO) gene interactions with environmental factors affecting on obesity and its impact on lifestyle interventions

BACKGROUND

The prevalence of obesity is influenced by environmental and genetic factors. Recently, it has been reported that an interaction between genotype and environmental factors can affect each other's effects on the phenotype. The purpose of this study is to evaluate the recent studies on the fat mass and obesity-associated (FTO) gene interactions with environmental factors affecting on obesity and the impact of these interactions on the success level of the lifestyle intervention.

METHODS

All articles published in English from June 1990 to June 2015 were studied.

RESULTS

In most studies, the role of the FTO risk alleles for obesity is significantly intensified through reduced physical activity and high calorie diet. Furthermore, the results of studies about the effect of FTO on the success level of lifestyle interventions have been contradictory. Some studies show that FTO genotype influences on the success of lifestyle interventions, while other studies did not report it.

CONCLUSION

The results of these studies generally indicate that the effect of the FTO gene on obesity may be influenced by environmental factors and lifestyle. In the other hand, the FTO genotype can affect the success of lifestyle interventions in the prevention and treatment of obesity. Future studies are crucial to elucidate relationships between FTO gene and lifestyle.