Effects of Citric Acid Supplementation on Hepatic Lipid Metabolism and Body Weight in Mice

Citric acid, a naturally found component of citrus fruits, is commonly added to beverages in Japan and marketed as a fatigue-relieving functional food. While some studies associate citric acid with insulin resistance and fatty liver disease, others suggest it enhances energy expenditure and lipid metabolism, leaving its effects on lipid metabolism unclear. To clarify these effects, we conducted a study where mice were given water with or without 0.6% free citric acid for 6 weeks. The group receiving citric acid showed reduced body weight, food intake, energy intake, and water consumption. However, no significant differences were observed in organ weights or energy efficiency. Hepatic enzyme activity (FASN), linked to fatty acid synthesis, was elevated, but lipolysis and cholesterol synthesis markers were unaffected. Plasma triglycerides and hepatic cholesterol were slightly elevated, but the results were not statistically significant. These findings suggest that citric acid may stimulate fatty acid synthesis without disrupting overall lipid metabolism in healthy mice consuming a standard diet.