Objective: The aim of the present study is to perform a systemic review of the previous studies executed on the association between obesity and folate. Method: In the present research, the selected keywords were scanned on the PubMed, Web of Science, Cochrane and Lilac databases between May and June, 2017 through Gazi University's network. In total, 4236 clinical, randomized controlled, cross-sectional and prospective studies were determined and 17 of these that specifically fit the aims of the present research were reviewed. This study involved an electronic literature search of databases on folic acid and obesity published in the English language between 2000 and 2016. Results: Of the 17 studies, 5 were based on folic acid supplementation and 12 were related with participants' folate status. As a general consequence of both intake and serum/status measurements of folic acid supplementation: It was found that obesity-associated metabolic changes might affect individual folate use and obese individuals had lower serum folate levels, although there was no change in folate intake. Conclusion: Overweight and obese individuals have lower serum folate concentrations when compared with individuals with normal weight. It is explained by increased use of folic acid, urinary excretion, dilution of blood volume, different levels in different tissues and changes in the endocrine functions of folate. Individuals with higher Body Mass Indexes have less supplement use, unhealthier diets and donot consume sufficient vegetables and fruits, all of which can affect decrease in folate levels. Furthermore, adiposity may affect folate absorption by intestinal epithelium.
Keywords: Adipose tissue; body mass index; folate; homocysteine; obesity.