Dietary glycemic index and glycemic load mediate the effect of CARTPT rs2239670 gene polymorphism on metabolic syndrome and metabolic risk factors among adults with obesity

INTRODUCTION

The importance of genetic and dietary factors in occurrence and progression of chronic diseases such as metabolic syndrome (MetS) has been established. However, complex interrelationships, including direct and indirect effects of these variables are yet to be clarified. So, our aim was to investigate the mediating role of glycemic indices in the relationship between CARTPT rs2239670 polymorphism, socio-demographic and psychological factors and metabolic risk factors and the presence of MetS in adults with obesity.

METHODS

In a cross-sectional study of 288 apparently healthy adults with obesity aged 20-50 years, dietary glycemic index (GI) and glycemic load (GL) were measured using a validated semi-quantitative food frequency questionnaire (FFQ). Biochemical parameters, blood pressure and anthropometric indicators were assayed by standard methods. Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Structural equation modeling (SEM) was used in the statistical analysis.

RESULTS

CARTPT rs2239670 had a positive direct effect on MetS (B = 0.037 ± 0.022; P = 0.043) and, on the other hand, this variant was found to be indirectly associated with MetS presence through mediation of GI (B = 0.039 ± 0.017; P = 0.009). CARTPT was a significant predictor of both dietary GI and GL (B = 1.647 ± 0.080 and B = 3.339 ± 0.242, respectively). Additionally, glycemic indicators appeared to mediate the association of age and gender with LDL-C (B = 0.917 ± 0.332; P = 0.006) and HDL (B = 1.047 ± 0.484; P = 0.031), respectively. GI showed a positive relationship with LDL-C (P = 0.024) in men and similar relationships were found between GL and LDL-C (P = 0.050) and cholesterol (P = 0.022) levels in women.

CONCLUSION

The SEM findings suggest a hypothesis of the mediating effect of glycemic indices in the relationship between genetic susceptibility to obesity and MetS presence. Our findings need to be confirmed with large prospective studies.

Dietary total antioxidant capacity interacts with a variant of chromosome 5q13-14 locus to influence cardio-metabolic risk factors among obese adults

Background

The association between cocaine- and amphetamine-regulated transcript prepropeptide gene (CARTPT) and obesity-related outcomes has shown in the epidemiological studies. Nevertheless, there is lack of data regarding the CARTPT gene-diet interactions in terms of antioxidant potential of diet. So, this study aimed to test CARTPT gene-dietary non-enzymatic antioxidant capacity (NEAC) interactions on cardio-metabolic risk factors in obese individuals.

Methods and material

The present cross-sectional study was carried out among 288 apparently healthy obese adults within age range of 20-50 years. Antioxidant capacity of diet was estimated by calculating the oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), total radical-trapping antioxidant parameter (TRAP) and Trolox equivalent antioxidant capacity (TEAC) using a semiquantitative food frequency questionnaire (FFQ). Genotyping for CARTPT rs2239670 polymorphism was conducted by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results

A significant interaction was revealed between CARTPT rs2239670 and dietary ORAC on BMI (PInteraction = 0.048) and fat mass percent (FM%) (PInteraction = 0.008); in A allele carriers, higher adherence to the dietary ORAC was related to lower level of BMI and FM%. And, the significant interactions were observed between FRAP index and rs2239670 in relation to HOMA (PInteraction = 0.049) and QUICKI (PInteraction = 0.048). Moreover, there were significant interactions of rs2239670 with TRAP (PInteraction = 0.029) and TEAC (PInteraction = 0.034) on the serum glucose level; individuals with AG genotype were more respondent to higher intake of TRAP.

Conclusion

The present study indicated that the relationships between CARTPT rs2239670 and obesity and its-related metabolic parameters depend on adherence to the dietary NEAC. Large prospective studies are needed to confirm our findings.

Interplay between fatty acid desaturase2 (FADS2) rs174583 genetic variant and dietary antioxidant capacity: cardio-metabolic risk factors in obese individuals

OBJECTIVE

Polymorphisms of the fatty acid desaturase (FADS) gene cluster have been associated with obesity and its-related consequences. This cross-sectional study aimed to investigate whether the adherence to dietary non-enzymatic antioxidant capacity (NEAC), reflecting the antioxidant potential of the whole diet, modifies the association of FADS2 rs174583 polymorphism with cardio-metabolic risk factors in obese adults.

METHODS

The present study included 347 healthy obese adults (aged 20-50 years). Dietary NEAC was assessed by a validated food frequency questionnaire with 147 items and estimated through total radical-trapping antioxidant parameters (TRAP), oxygen radical absorbance capacity (ORAC), and ferric reducing ability of plasma (FRAP) with the use of published databases. FADS2 rs174583 polymorphism was characterized using PCR-RFLP. ANCOVA multivariate interaction model was used to analyze gene-diet interactions.

RESULTS

after adjustment for the confounding variables (age, physical activity, SES and WC), this study showed significant interactions between rs174583 polymorphism and adherence to dietary ORAC on the serum cholesterol (P _Interaction = 0.029), LDL-C (P _Interaction = 0.025) and HDL-C levels (P _Interaction = 0.049) among the male group; minor allele carriers who had the highest adherence to the NEAC (ORAC) showed a better metabolic profile (lower TG and LDL-C and higher HDL-C) (P < 0.05). Among women, the dietary ORAC-rs174583 interactions were statistically significant for the serum insulin concentration (P _Interaction = 0.020), QUICKI (P _Interaction = 0.023) and HOMA-IR (P _Interaction = 0.017); the highest QUICKI and the lowest HOMA-IR and serum insulin levels were observed in the CC homozygote carriers with the moderate compliance with the dietary ORAC (P < 0.05). In addition, the dietary TRAP modified the association between FADS2 variant and change in LDL-C levels (P _Interaction = 0.037); the homozygous wild-type (CC) women who placed in the top tertile of TRAP had significantly the lowest LDL-C levels than those in the second tertile (P < 0.05).

CONCLUSION

These data indicate that the FADS2 rs174583 polymorphism interacts with the dietary NEAC to influence cardio-metabolic risk factors in obese subjects. Replication in prospective cohort studies among other populations is required to confirm the results of our study.

Factors associated with health-related quality of life in women using path analyses: mediation effect of the adiposity traits

Background

The current work aimed to investigate the mediating role of adiposity traits in the relationship between eating behaviors, sleep quality, socio-demographic factors, and the health-related quality of life in women of reproductive age in northwest of Iran.

Methods

In the current cross-sectional study, a total of 278 overweight and obese women of reproductive age (20–49 y) were enrolled. Anthropometric assessments were performed. Pittsburgh sleep quality index (PSQI) was used for assessment of sleep quality while Short Form 36 (SF-36) questionnaire was used to measure health-related quality of life (HRQoL). Three-Factor Eating Questionnaire-R18 (TFEQ-R18) was used to measure eating behaviors. Path analysis was used to test the relationships between parameters.

Results

Age was found to be indirectly and negatively associated with mental component score (MCS) (B = − 0.040; P = 0.049) and physical component score (PCS) (B = − 0.065; P = 0.036) through mediatory effects of obesity. Additionally, education was seen to be indirectly and positively related to MCS (B = 0.529; P = 0.045) and PCS (B = 0.870; P = 0.019), respectively. On the other hand, obesity (B = 0.608; P = 0.018) and PSQI score (B = − 0.240; P = 0.034) had direct associations with MCS. Age (B = − 0.065; P = 0.036) and education (B = 0.870; P = 0.019) were also directly associated with obesity.

Conclusions

Obesity seemed to mediate the effects of socio-demographic parameters on HRQoL. Poor sleep quality was also related to impairment of HRQoL. Further studies are needed to confirm these results.

The Interaction Between Fatty Acid Desaturase-2 (FADS2) rs174583 Genetic Variant and Dietary Quality Indices (DASH and MDS) Constructs Different Metabolic Phenotypes Among Obese Individuals

Background and Aim: Genetic variation in fatty acid desaturases (FADS) has previously been linked to several diet-related diseases. We aimed to determine whether the FADS2 rs174583 variant interacts with the Dietary Approach to Stop Hypertension (DASH) score and Mediterranean dietary score (MDS) to influence cardio-metabolic risk factors among obese adults. Methods: This cross-sectional study was performed among 347 apparently healthy obese adults (aged 20-50 years). Dietary quality indicator scores (DASH and MDS) were generated using a validated 147-item Food Frequency Questionnaire (FFQ). The FADS2 rs174583 variant was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The gene-diet interaction was analyzed by the ANCOVA multivariate interaction model. Results: A significant interaction was observed between rs174583 and adherence to the DASH score in relation to serum triglyceride (TG) concentration among the female group (P Interaction = 0.046); CT-genotype carriers who were assigned to the second tertile of DASH compared with those in the first tertile had a lower TG level (P < 0.05). Another significant interaction was revealed between adherence to MDS score and rs174583 polymorphism on serum glucose levels (P Interaction = 0.044); the lowest mean of glucose level was observed in homozygous minor subjects (TT) in the third tertile of MDS, in comparison with other tertiles of this dietary index (P < 0.05). There was a similar significant interaction between DASH and rs174583 in relation to diastolic blood pressure (P Interaction = 0.038) among the male group. Additionally, a significant positive association was found between TT genotype and odds of having high TG both in the crude (OR, 3.21; 95% CI, 1.02-10.14) and adjusted (OR, 3.58; 95% CI, 1.07-11.97) models, taking into account different confounders. Conclusion: Adherence to the dietary quality indicators (DASH and MDS) modified the relationship between FADS2 rs174583 polymorphism and cardio-metabolic risk factors in obese subjects. Prospective cohort studies are needed to confirm the results of our study.

Sugar-sweetened beverages increases the risk of hypertension among children and adolescence: a systematic review and dose-response meta-analysis

BACKGROUND

In the current systematic review and meta-analysis, we summarized the studies that evaluated the effects of sugar-sweetened beverages (SSBs) intake on blood pressure among children and adolescents.

METHODS

In a systematic search from PubMed, Scopus, Embase and Cochrane electronic databases up to 20 April 2020, the observational studies that evaluated the association between sugar-sweetened beverages intake and hypertension, systolic or diastolic blood pressure (SBP, DBP) were retrieved.

RESULTS

A total of 14 studies with 93873 participants were included in the current meta-analysis. High SSB consumption was associated with 1.67 mmHg increase in SBP in children and adolescents (WMD: 1.67; CI 1.021-2.321; P < 0.001). The difference in DBP was not significant (WMD: 0.313; CI -0.131- 0.757; P = 0.108). High SSB consumers were 1.36 times more likely to develop hypertension compared with low SSB consumers (OR: 1.365; CI 1.145-1.626; P = 0.001). In dose-response meta-analysis, no departure from linearity was observed between SSB intake and change in SBP (P-nonlinearity = 0.707) or DBP (P-nonlinearity = 0.180).

CONCLUSIONS

According to our finding, high SSB consumption increases SBP and hypertension in children and adolescents.

Melanocortin-4 receptor (MC4R) rs17782313 polymorphism interacts with Dietary Approach to Stop Hypertension (DASH) and Mediterranean Dietary Score (MDS) to affect hypothalamic hormones and cardio-metabolic risk factors among obese individuals

BACKGROUND AND AIM

The association with obesity of a common variant near the melanocortin-4 receptor (MC4R) gene (rs17782313) has been indicated in various studies. Adherence to dietary quality indices also have shown to have potential favorable effects on obesity-related health outcomes. However, no study has examined the interaction between rs17782313 and the Dietary Approach to Stop Hypertension (DASH) score and the Mediterranean Dietary Score (MDS) on cardio-metabolic risk factors and hypothalamic hormones. Therefore, the purpose of the current study was to examine whether adherence to these dietary quality indices modifies the association of the MC4R rs17782313 polymorphism with cardio-metabolic risk factors and hypothalamic hormones among obese adults.

METHOD

Two hundred eighty-eight healthy obese adults were recruited in this cross-sectional study. Diet quality indices, including DASH score and MDS, were calculated from a validated 147-item food frequency questionnaire (FFQ). MC4R s17782313 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). An ANCOVA multivariate interaction model was used to assess the gene-diet interaction.

RESULTS

Significant interactions were detected between DASH score and MC4R rs17782313 genotypes on systolic blood pressure (SBP), atherogenic index of plasma (AIP), and serum glucose and triglyceride (TG) among the female group (p_Interaction < 0.05). In the male group, there were gene-DASH and gene-MDS interactions in relation to serum glucose concentration and plasma α-melanocyte stimulating hormone (MSH) levels, but these were found only in multi-adjusted interaction models (p_Interaction < 0.05). In addition, there was a significant interaction between MC4R rs17782313 polymorphism and DASH score on plasma agouti-related peptide (AgRP) concentrations in the female group in a multivariate interaction model (p_Interaction < 0.05). An inverse association between DASH score and chance of having the CC genotype in a multivariate-adjusted model among women was also revealed.

CONCLUSION

MC4R rs17782313 interacts with healthy dietary pattern (DASH score and MDS) to influence cardio-metabolic risk factors and hypothalamic hormones in obese individuals. Prospective cohort studies are needed to further assess these findings.

The interaction between dietary Non-Enzymatic Antioxidant Capacity (NEAC) with variants of Melanocortin-4 receptor (MC4R) 18q21.23-rs17782313 locus on hypothalamic hormones and cardio-metabolic risk factors in obese individuals from Iran

Background: In the current study, we aimed to evaluate the interaction between dietary Non-Enzymatic Antioxidant Capacity (NEAC) and rs17782313 polymorphism on hypothalamic hormones and cardio-metabolic risk factors. Methods: A total of 287 subjects (aged 20-50 years, 147 males and 140 females) enrolled in the cross-sectional study. Dietary NEAC was assessed using databases of NEAC measurements compiled from outcomes for three different analyses: oxygen radical absorbance capacity (ORAC), ferric reducing-antioxidant power (FRAP), and total radical-trapping antioxidant parameter (TRAP) and genotyping for the near MC4R rs17782313 was carried out by Polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) method. Results: The significant interactions were found between adherence to the dietary NEAC and MC4R rs17782313 in relation to high-density lipoprotein-cholesterol (HDL-C), glucose, α-melanocyte stimulating hormone (α-MSH), insulin and quantitative insulin sensitivity check index (QUICKI) (P _Interaction = 0.03, 0.01, 0.04, 0.04 and 0.04, respectively). In homozygous subjects for the minor allele, the serum insulin level and QUICKI in participants with the highest adherence to TRAP were significantly higher than those with the lowest adherence (p < 0.001). There was a significant inverse association between high ORAC score and risk of metabolic syndrome even after adjusting for potential confounders (OR: 0.33; 95%CI:0.13-0.81) and also a significant inverse association between high NEAC (ORAC, FRAP and TRAP assays) score and high triglyceride (TG) level was found in obese adults. Conclusion: In conclusion, our study found for the first time that the NEAC significantly interacts with the rs17782313 genotypes to influence several metabolic risk factors in obesity.

Dietary quality indices modifies the effects of melanocortin-4 receptor (MC4R) rs17782313 polymorphism on cardio-metabolic risk factors and hypothalamic hormones in obese adults

BACKGROUND

Although the Melanocortin-4 Receptor (MC4R) gene rs17782313 C/T has been consistently related to obesity risk, the interaction between MC4R polymorphism and diet quality indices on cardio-metabolic risk factors has not yet investigated. Therefore we aimed to test this hypothesis.

METHODS

This cross-sectional study recruited 188 (96 males and 92 females) healthy obese adults aged 20-50 years. Diet quality indices including Healthy Eating Index-2015 (HEI-2015) and Diet Quality Index-International (DQI-I) were constructed using data from a validated food frequency questionnaire. MC4R s17782313 were genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). The interaction between MC4R polymorphism and diet quality indices was tested by Analysis of covariance (ANCOVA) multivariate interaction model.

RESULTS

There were significant gene-diet interactions between rs17782313 and HEI-2015 (P Interaction < 0.05) in modulating low-density lipoprotein cholesterol (LDL-C) levels among female group; rare allele heterozygotes of rs17782313 had highest mean of LDL-C concentration when placed in second tertile of HEI (P < 0.05). Moreover, rs17782313 and both indices (HEI and DQI-I) had significant interaction on serum glucose concentrations, systolic and diastolic blood pressure (SBP, DBP) in males (P Interaction < 0.05); when adherence to these indices was low, the obesity risk allele was associated with serum glucose concentrations, SBP and DBP. These gene-diet interactions remained significant even after adjustment for potential confounders.

CONCLUSION

Our study showed that MC4R rs17782313 interacts with adherence to the dietary quality indices (HEI and DQI-I) to influence several cardio-metabolic risk factors in obese male and females. Further large prospective studies are warranted to confirm our findings.

A structural equation modeling approach for the association of a healthy eating index with metabolic syndrome and cardio-metabolic risk factors among obese individuals

Background

Numerous studies have evaluated the association between dietary factors and cardiovascular risk among patients with chronic disease. It is worthwhile to assess these associations in a combination model rather than in an isolated form. In the current study, we aimed to use structural equation modeling (SEM) to assess the association of adherence to a healthy eating index (HEI)-2015 with socio-demographic factors, psychological characteristics, metabolic syndrome (MetS) and other cardio-metabolic risk factors among obese individuals.

Methods

This cross-sectional study was conducted among 188 healthy obese adults (96 males and 92 females) aged 20–50 years in Tabriz. A validated semi-quantitative food frequency questionnaire (FFQ) was used to record dietary intake and to estimate HEI-2015. Anthropometric parameters, blood pressure and biochemical measurements were evaluated according to standard protocols. Interrelationships among socio-demographic parameters and HEI with cardio-metabolic risk factors were analyzed using SEM.

Results

The results of SEM analysis revealed that HEI mediated the association between age and several cardio-metabolic risk factors including fat mass (FM), fat free mass (FFM), systolic blood pressure (SBP) and high-density lipoprotein (HDL) (p < 0.05). Moreover, adherence to Dietary Guidelines for Americans (DGA) appears to mediate association between gender and waist circumference (B = -9.78), SBP (B = -4.83), triglyceride (B = -13.01) and HDL (B = 4.31). HEI also mediated indirect negative effects of socioeconomic status on FM (B = -0.56), FFM (B = -0.25), SBP (B = -0.55) and diastolic blood pressure (DBP) (B = -0.3). Additionally, depression and age had indirect unfavorable effects on some insulin resistance indices such as homeostasis model assessment of insulin resistance (B = 0.07; p<0.05, for age) and quantitative insulin sensitivity check index (p<0.05, for age and depression) via HEI. High adherence to HEI was found to be inversely associated with MetS risk (p<0.05).

Conclusion

Adherence to HEI-2015 seems to mediate the effect of socio-demographic parameters and mental health on cardio-metabolic risk factors as well as MetS risk. Further studies are needed to confirm these findings.

A systematic review and meta-analysis of the effects of soy on serum hs-CRP

BACKGROUND & AIM

The results of studies about the effect of soy products on serum highly sensitive C-reactive protein (hs-CRP) are inconsistent. The aim of this systematic review and meta-analysis of randomized clinical trials (RCTs) was to investigate the effect of soy products intake on serum hs-CRP concentration.

METHODS

We searched PubMed, EMBASE, Science Direct, ISI Web of Science, Google Scholar and Cochrane Central Register of Controlled Trials up to December 2016 without language restrictions. Random-effect model was used for quantitative data synthesis.

RESULTS

Thirty-six studies were included in our analyses. A meta-analysis revealed a non-significant reduction in serum hs-CRP concentrations following soy products consumption, -0.19 (mg/L) (95% CI: -0.49 to 0.09; I2 = 95.6%). Subgroup analyses suggested that natural soya products may reduce plasma levels of CRP by -0.18 mg/L (95% CI: -0.28 to -0.08; I2: 11.6) in comparison to other source of isoflavones (soya extracts, supplements). Moreover, the effect was stronger among subjects with baseline hs-CRP concentrations of less than 2.52 mg/L, -0.15 (95% CI: -0.27 to -0.02; I2: 34.6). A meta-regression analysis revealed that dosage of isoflavones seems to be a strong predictor of the effect of soya on serum hs-CRP levels.

CONCLUSION

Present review of RCTs published up to December 2016 did not provide strong evidence regarding the beneficial effect of soya products consumption on blood hs-CRP concentrations. However, it appears that natural soya products may reduce plasma levels of hs-CRP in comparison to other source of isoflavones. Large and well-designed studies are recommended to confirm this conclusion.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018069371.

Dietary fat intake and functional dyspepsia

A few studies have assessed the effects of fat intake in the induction of dyspeptic symptoms. So, the aim of this study was to review the articles regarding the dietary fat intake and FD. We used electronic database of PubMed to search. These key words were chosen: FD, dietary fat, dyspeptic symptom, energy intake and nutrients. First, articles that their title and abstract were related to the mentioned subject were gathered. Then, full texts of related articles were selected for reading. Finally, by excluding four articles that was irrelevant to subject, 19 relevant English papers by designing clinical trial, cross-sectional, case–control, prospective cohort, and review that published from 1992 to 2012 were investigated. Anecdotally, specific food items or food groups, particularly fatty foods have been related to dyspepsia. Laboratory studies have shown that the addition of fat to a meal resulted in more symptoms of fullness, bloating, and nausea in dyspeptic patients. Studies have reported that hypersensitivity of the stomach to postprandial distension is an essential factor in the generation of dyspeptic symptoms. Small intestinal infusions of nutrients, particularly fat, exacerbate this hypersensitivity. Moreover, evidence showed that perception of gastric distension increased by lipids but not by glucose. Long chain triglycerides appear to be more potent than medium chain triglycerides in inducing symptoms of fullness, nausea, and suppression of hunger. Thus, Fatty foods may exacerbate dyspeptic symptoms. Therefore, it seems that a reduction in intake of fatty foods may useful, although this requires more evaluations.

Evaluation of the relationship between major dietary patterns and uninvestigated reflux among Iranian adults

OBJECTIVES

The etiology of uninvestigated reflux is largely unknown. Although diet has been associated with uninvestigated reflux, the role of dietary patterns is not clear yet. The aim of this study was to investigate dietary patterns in relation to uninvestigated reflux among Iranian adults.

METHODS

This cross-sectional study was carried out within the framework of SEPAHAN (Study on the Epidemiology of Psychological, Alimentary Health and Nutrition) among Iranian adults. Dietary data were collected using a self-administered, 106-item, dish-based, semiquantitative food frequency questionnaire. Uninvestigated reflux was considered to be present when an individual reported to be suffering from heartburn sometimes or frequently in the preceding 3 mo. Specific dietary patterns were identified using factor analysis.

RESULTS

Complete information from 3846 individuals was available for statistical analysis. We identified four major dietary patterns: fast food, traditional, vegetarian, and Western. After controlling for potential confounders, no overall significant associations were found between these dietary patterns and uninvestigated reflux. However, participants in the third quintile of the traditional dietary pattern had greater odds of uninvestigated reflux, either in the crude (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.09-1.74) or the adjusted (OR, 1.52; 95% CI, 1.16-2.00) model taking into account different confounders. After controlling for age, men in the second (OR, 1.64; 95% CI, 1.10-2.45) and women in the fourth (OR, 1.47; 95% CI, 1.02-2.11) quintiles of the fast food dietary pattern were more likely to have uninvestigated reflux. Moreover, in the age-adjusted model, men in the second (OR, 1.72; 95% CI, 1.14-2.59) and fourth (OR, 1.56; 95% CI, 1.03-2.35) quintiles, and women in the second (OR, 1.48; 95% CI, 1.08-2.04) quintile of the traditional dietary pattern were at higher risk for being diagnosed with uninvestigated reflux.

CONCLUSION

Although the present study showed no statistically significant associations between major dietary patterns and the risk for uninvestigated reflux, relative positive associations were found between uninvestigated reflux and adherence to either fast food or traditional dietary patterns, suggesting that these contribute to the risk for developing reflux.

The association between different kinds of fat intake and breast cancer risk in women

So far several animal and case-control studies have confirmed this hypothesis that dietary fat increases the risk of breast cancer. However, cohort studies have not shown this relationship. The aim of this study was to review the studies on the relationship between dietary fat intake and breast cancer risk among women. Electronic database PubMed and Google Scholar were searched using the key words: Breast cancer, dietary fat, serum estrogen, saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The evidence of the studies regarding to the association of total and subtypes of fat intake with breast cancer risk are inconsistent. Several studies have shown that, among several types of fat, SFAs and w-3 PUFA intake are associated with an increased and reduced risk of breast cancer, respectively. The relationship between MUFAs intake and breast cancer risk is conflicting. Narrow ranges of fat intake among populations, measurement errors, high correlation between specific types of dietary fat, the confounding variables like body fatness and high-energy intake and other dietary components such as fiber and antioxidants might be probable explanations for these inconsistent results. Although we are not at a stage where we can justifiably advise women to reduce their fat intake to decrease the risk of developing breast cancer, it seems the current guidelines to lower total fat consumption and recommendation to consumption of unsaturated fats such as MUFAs and w-3 fatty acids and also reduction of SFAs (meat and dairy products) intake to avoid heart disease is also useful for breast cancer risk.