Non-alcoholic fatty liver disease (
NAFLD) is now recognized as the most prevalent hepatic disorder worldwide, and an unhealthy lifestyle is the leading risk factor for its occurrence.
Vitamin C (VC) has been suggested to protect
NAFLD, whereas evidence from randomized controlled trials (RCTs) is sparse. In this study, we aimed to investigate the potential benefits of VC supplementation daily on liver health and associated parameters in patients with
NAFLD. In this double-blind, RCT, 84 patients with
NAFLD, aged 18-60 years old, were assigned to 12 weeks of oral treatment with either low (250 mg/day, n = 26), medium (1,000 mg/day,
n = 30), or high (2,000 mg/day, n = 28) doses of VC supplements. After the intervention, the Medium group had a more significant decrease in
aspartate aminotransferase [Medium, -5.00 (-10.25, -1.75) vs. High, -2.50 (-7.75, 0.00), P = 0.02] and
alanine aminotransferase [Medium, -8.00 (-18.00, -1.75) vs. High, -3.50 (-13.75, 4.25), P = 0.05; Medium vs. Low, -3.00 (-9.00, 5.50), P = 0.031]. The levels of other indicators of liver health, such as gamma-glutamyl
transferase,
alkaline phosphatase, total
bilirubin, and direct
bilirubin were decreased after the intervention but comparable among the three groups and so did the parameters of
glucose metabolism, such as fasting
insulin, fasting
glucose, and homeostasis model assessment for
insulin resistance. The plasma level of VC in patients and total
adiponectin and high molecular weight (HMW)
adiponectin levels were also elevated but not in a dose-dependent manner. Meanwhile, analysis of fecal microbiota composition showed an increase in the alpha diversity (Abundance-based Coverage Estimator (ACE), Shannon, chao1, and Simpson) both in the Low and the Medium groups. A total of 12 weeks of VC supplementation, especially 1,000 mg/day, improved liver health and
glucose metabolism in patients with
NAFLD. The elevated plasma levels of VC, total and HMW
adiponectin, and the improvement of intestinal microbiota may have made some contributions.