Folic Acid Supplementation Alters Adipose Tissue Lipid Metabolism

Abstract

Mandatory folate fortification polices in Canada and the United States has resulted in high levels of circulating folate in a large proportion of the population. At the same time, a trend toward increased energy intake and reduced energy expenditure has lead to an increased prevalence of obesity, characterized by an accumulation of TAG in adipose tissue. Folate plays an essential role in maintaining S‐adenosylmethionine (AdoMet), an important biological methyl‐donor. AdoMet functions in the formation of phosphatidylcholine from phosphatidylethanolamine catalyzed by the enzyme phosphatidylethanolamine N‐methyltransferase (PEMT). PEMT activity contributes to storage of triacylglycerol (TAG) in adipocytes.The objective of this study was to investigate the effect of dietary folic acid supplementation on adipose tissue lipid metabolism. Sprague Dawley rats were fed a high fat diet containing 0.75 mg or 7.5 mg folic acid for 12 weeks.Adipose tissue weight was significantly greater in rats fed excess folic acid. This was accompanied by an increased expression of genes involved in re‐esterification of fatty acids to glycerol, suggesting elevated TAG formation. Up‐regulation of genes involved in phospholipid biosynthesis supports increased storage of TAG in adipocytes upon folate supplementation.In summary, folate supplementation enhances TAG storage in adipose tissue of high fat diet‐fed rats.Grant Funding Source : CIHR, Food and Health Innovation Initiative