Vitamin D supplementation improves insulin resistance in NAFLD

In patients with nonalcoholic fatty liver disease (NAFLD), additional treatment with vitamin D leads to better insulin resistance profiles, reports a recent meta-analysis. Vitamin D may serve as an adjunct intervention in this population.

Drawing from the databases of PubMed, Google Scholar, Cochrane, and Science Direct, researchers retrieved seven studies eligible for meta-analysis, yielding a total of 735 participants.

The homeostatic model assessment of insulin resistance, set as the primary measure of insulin resistance, was significantly reduced in NAFLD patients on vitamin D supplementation (pooled mean difference, –1.06, 95 percent confidence interval [CI], –1.66 to –0.45; p=0.0006).

Moreover, vitamin D led to a significant drop in alanine aminotransferase levels (pooled mean difference, –4.44, 95 percent CI, –8.24 to –0.65; p=0.02) without significantly altering concentrations of aspartate aminotransferase. Those on vitamin D supplementation likewise had higher serum vitamin D levels (pooled mean difference, 17.45, 95 percent CI, 8.33–26.56; p=0.0002).

In terms of methodological quality, all studies passed evaluation according to the Cochrane Collaboration’s risk-of-bias method. In particular, most studies were of good quality in terms of random sequence generation and allocation concealment, which led to low risks of selection bias.

“The current systematic review and meta-analysis provide more reports that vitamin D supplementation improves insulin resistance in NAFLD patients,” the researchers said. “Although similar meta-analyses had been conducted, the current meta-analysis provides updated literature with more randomized controlled trials involved, hence providing stronger evidence for the effect of vitamin D supplementation on insulin resistance.”