The relationship between 25-hydroxyvitamin D concentration and liver enzymes in overweight or obese adults: Cross-sectional and interventional outcomes

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Abstract

Vitamin D deficiency is prevalent in individuals with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis. However, there is limited and inconsistent data on the effect of vitamin D supplementation on liver function. Hepatic enzymes have been used as surrogate markers for NAFLD and have been associated with metabolic syndrome. We examined the relationships between 25-hydroxyvitamin D (25(OH)D) and γ-glutamyl transferase (GGT), alanine aminotransferase (ALT), alkaline phosphatase (ALP) in 120 drug-naïve individuals with no history of liver disease. In addition, the effect of vitamin D supplementation (100,000 loading dose of cholecalciferol followed by 4000IU daily for 16 weeks) on hepatic enzymes was investigated in a subgroup of 54 vitamin D-deficient overweight or obese individuals (28 randomised to cholecalciferol and 26 to placebo). Hepatic enzymes, anthropometric parameters, lipid profile, insulin sensitivity (hyperinsulinaemic-euglycaemic clamp, M value) and high sensitivity C-reactive protein (hs-CRP) were measured before and after the intervention. In the cross-sectional study, levels of GGT and ALT were higher in men compared to women (both p = 0.001). There were no significant differences in GGT, ALT and ALP between vitamin D categories (25(OH)D<. 25. nmol/L, 25-50. nmol/L, and >50. nmol/L) and no relationships were found between the three enzymes and 25(OH)D before and after adjustment for age, sex, BMI, WHR, and insulin sensitivity (all p. >0.5). In the randomised trial, 25(OH)D concentrations increased in the vitamin D group (mean change 57.0. ±. 21.3. nmol/L) compared to the placebo group (mean change 1.9. ±. 15.1. nmol/L). Mean changes in GGT, ALT and ALP were not significantly different between vitamin D and placebo groups (all p. >0.2). Change in 25(OH)D concentration was not correlated with changes in GGT, ALT and ALP before and after adjustments for age and sex (all p. >0.1).In summary, 25(OH)D concentrations were not related to hepatic enzymes in drug-naive adults with no history of liver disease, and vitamin D supplementation had no effect on the serum levels of hepatic enzymes in vitamin D-deficient and overweight or obese, otherwise healthy individuals. Hence, vitamin D supplementation is unlikely to prevent incident NAFLD.

Original languageEnglish
Pages (from-to)193-199
Number of pages7
JournalJournal of Steroid Biochemistry and Molecular Biology
Volume177
DOIs
Publication statusPublished - Mar 2018

Keywords

  • 25-Hydroxyvitamin D (25(OH)D)
  • Alanine aminotransferase (ALT)
  • Alkaline phosphatase (ALP)
  • Insulin resistance
  • Obesity
  • γ-Glutamyl transferase (GGT)

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