Tehran University of Medical Sciences Journal of Nutritional Sciences and Dietetics 1 1 2015 10 05 28 36 EN Mahdieh Nourmohammdi Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran Hanieh-Sadat Ejtahed Obesity Research Center, Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran Parvin Mirmiran Obesity Research Center, Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran Azita Hekmatdoost Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2015 10 05 2015 10 05 Diet as a part of lifestyle plays a pivotal role in the development of metabolic syndrome and its consequences. Fatty acid composition as a part of dietary intake affects blood fatty acid concentrations, insulin sensitivity and different metabolic pathways associated with the occurrence and consequences of the metabolic syndrome. The aim of this review is to evaluate the effects of dietary fatty acid composition on metabolic syndrome (MetS) and its components. A search was conducted through PubMed, Google scholar and Science Direct using keywords including metabolic syndrome, MetS, diet, fatty acid composition, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, omega3, omega6 and fish oil, insulin resistance, hyperlipidemia, obesity and blood glucose. We included English articles published from 1995 to 2014. Based on the results of the studies reviewed, intake of saturated fatty acids by increasing LDL-C, total cholesterol and oxidized LDL and arterial stiffness was associated with increased insulin resistance and metabolic syndrome. In contrast, supplements containing omega-3 and monounsaturated fatty acids such as fish and rapeseed oil can reduce the risk of metabolic syndrome and its consequences risk factors by lowering triglycerides,  cholesterol,  inflammation  and  oxidative  stress.  Low  intake  of saturated fatty acids and monounsaturated fatty acids with increased intake of omega-3  polyunsaturated  fatty  acids  may  be  useful  in  reducing  the  risk  of metabolic syndrome and its consequences. https://jnsd.tums.ac.ir/index.php/jnsd/article/view/5 https://jnsd.tums.ac.ir/index.php/jnsd/article/download/5/5