Nutr Res Pract.  2020 Aug;14(4):309-321. 10.4162/nrp.2020.14.4.309.

Folic acid supplementation prevents high fructose-induced non-alcoholic fatty liver disease by activating the AMPK and LKB1 signaling pathways

  • 1Department of Food and Nutrition, College of Bio-Nano Science, Hannam University, Daejeon 34054, Korea


The present study aimed to evaluate the effects of folic acid supplementation in high-fructose-induced hepatic steatosis and clarify the underlying mechanism of folic acid supplementation.
Male SD rats were fed control, 64% high-fructose diet, or 64% high-fructose diet with folic acid for eight weeks. Plasma glutamate-pyruvate transaminase, glutamate-oxaloacetate transaminase, lipid profiles, hepatic lipid content, S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) were measured.
The HF diet significantly increased hepatic total lipid and triglyceride (TG) and decreased hepatic SAM, SAH, and SAM:SAH ratio. In rats fed a high fructose diet, folic acid supplementation significantly reduced hepatic TG, increased hepatic SAM, and alleviated hepatic steatosis. Moreover, folic acid supplementation in rats fed high fructose enhanced the levels of phosphorylated AMP-activated protein kinase (AMPK) and liver kinase B (LKB1) and inhibited phosphorylation of acetyl coenzyme A carboxylase (ACC) in the liver.
These results suggest that the protective effect of folic acid supplementation in rats fed high fructose may include the activation of LKB1/AMPK/ACC and increased SAM in the liver, which inhibit hepatic lipogenesis, thus ameliorating hepatic steatosis. The present study may provide evidence for the beneficial effects of folic acid supplementation in the treatment of non-alcoholic fatty liver disease.


Folic acid; fructose; fatty liver; AMP-activated protein kinase; S-adenosylmethionine


  • Fig. 1 Effect of folic acid supplementation on the bodyweight of high-fructose-fed rats. Male SD rats were fed C, HF, or HF+FA groups for 8 weeks. The results are presented as the mean ± SD (n = 8). Data were analyzed by ANOVA.C, control; HF, high-fructose diet; HF+FA, high-fructose diet with folic acid; ANOVA, analysis of variance.

  • Fig. 2 Effects of folic acid supplementation on fasting blood glucose, GPT, and GOT in high-fructose-fed rats. Male SD rats were fed C, HF, or HF+FA groups for 8 weeks. Each bar presents the mean ± SD (n = 8).GPT, glutamate-pyruvate transaminase; GOT, glutamate-oxaloacetate transaminase; C, control; HF, high-fructose diet; HF+FA, high-fructose diet with folic acid; ANOVA, analysis of variance.a-cDifferent letters mean significant difference according to ANOVA, Duncan's test (P < 0.05).

  • Fig. 3 Effects of folic acid supplementation on plasma lipids in high-fructose-fed rats. (A) Plasma TG (B) Plasma TC (C) HDL-C. Each bar presents the mean ± SD (n = 8).TG, triglyceride; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; ANOVA, analysis of variance; C, control; HF, high-fructose diet; HF+FA: high-fructose diet with folic acid.a,bDifferent letters mean significant difference according to ANOVA, Duncan's test (P < 0.05).

  • Fig. 4 Effects of folic acid supplementation on liver lipid accumulation in high-fructose-fed rats. (A) Liver TG (B) Liver total lipid content (C) Liver sections stained with H&E. Each bar presents the mean ± SD (n = 8). The images were captured using a Leica DMIL LED optical microscope (Leica, Wetzlar, Germany).TG, triglyceride; H&E, hematoxylin and eosin; ANOVA, analysis of variance; C, control; HF, high-fructose diet; HF+FA, high-fructose diet with folic acid.a,bDifferent letters mean significant difference according to ANOVA, Duncan's test (P < 0.05).

  • Fig. 5 Effect of folic acid supplementation on liver SAM, SAH, and SAM:SAH ratio in high-fructose-fed rats. (A) Liver SAM, (B) Liver SAH, and (C) Liver SAM:SAH ratio. Each bar presents the mean ± SD (n = 8).SAM, S-adenosylmethionine; SAH, S-adenosylhomocysteine; ANOVA, analysis of variance; C, control; HF, high-fructose diet; HF+FA, high-fructose diet with folic acid.a-cDifferent letters mean significant difference according to ANOVA, Duncan's test (P < 0.05).

  • Fig. 6 Effects of folic acid supplementation on hepatic expression of pLKB1 & LKB1 (A), pAMPK & AMPK (B), and pACC & ACC (C) protein in high-fructose-fed rats. Each bar presents the mean ± SD (n = 8).ACC, acetyl-CoA carboxylase; AMPK, AMP-activated protein kinase; LKB1, liver protein kinase B1; C, control; HF, high-fructose diet; HF+FA, high-fructose diet with folic acid.a,bDifferent letters mean significant difference according to ANOVA, Duncan's test (P < 0.05).


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