Vitamin D Improves Insulin Measures

By: Robert M. Blair, Ph.D. – Strategic Research Scientist

Vitamin D deficiency has been shown to be a common occurrence and to be linked to several chronic health conditions. While most studies have explored the relationship between vitamin D levels and health in populations with chronic health conditions, two recent studies have reported that blood levels of vitamin D may have beneficial effects on insulin resistance in healthy populations.

In one study, researchers conducted a cross-sectional analysis in 1,807 healthy Korean people where blood levels of vitamin D, fasting glucose and insulin levels were measured

[1]. The results of this analysis indicated that those with the lowest serum levels of vitamin D (< 9.7 ng/ml) were at the greatest risk for insulin resistance, a risk factor for diabetes and heart disease. This study further showed that the risk for insulin resistance was almost doubled in obese subjects with low serum vitamin D levels compared to non-obese individuals with the highest levels of serum vitamin D.

A second study looked at the potential benefit of vitamin D supplementation on blood glucose levels and insulin resistance in a population of healthy Japanese adults [2]. In this study, the participants were randomly assigned to receive either vitamin D3 (420 IU [i.e. 10.5 µg]) or placebo daily for one year. Blood levels of insulin and glucose were assessed at the start of the study and again upon completion of the study. After one year of supplementation, blood levels of vitamin D increased. Additionally, fasting glucose levels and insulin resistance significantly decreased after one year of vitamin D supplementation.

Together, these studies indicate that vitamin D supplementation can increase blood levels of vitamin D and improve insulin resistance and blood glucose levels in healthy adults. In turn, these beneficial effects might reduce one’s risk for diabetes and heart disease.


  1. Ock SY, Ha KH, Kim BK, Kim HC, Shim JS, Lee MH, Yoon YM, Kim DJ. Serum 25-hydroxyvitamin D concentration is independently inversely associated with insulin resistance in the healthy, non-obese Korean population. Diabetes Metab J 2016; Jul 26. [Epub ahead of print]
  2. Sun X, Cao ZB, Tanisawa K, Ito T, Oshima S, Higuchi M. Vitamin D supplementation reduces insulin resistance in Japanese adults: a secondary analysis of a double-blind, randomized, placebo-controlled trial. Nutrition Research 2016, Published online ahead of print, doi: 10.1016/j.nutres.2016.07.006

By |2018-12-12T21:44:25+00:00September 21st, 2016|Supplements|0 Comments

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