Chronic inflammation occurs in people with type 2 diabetes at a greater level than that of the healthy population. However, the outcome of a meta-analysis reported on March 27, 2018, in Nutrition Reviews revealed that supplementing with vitamin D could help.
The pooled analysis, which included 1,270 type 2 diabetics enrolled in 20 randomized, controlled trials, found "level 1" evidence that vitamin D supplementation could lower chronic low-grade inflammation. (Level 1 evidence is the highest level of evidence for clinical studies and is considered the most reliable of five established grades of evidence.) In comparison with subjects in the control groups, participants who received any form, route, and duration of vitamin D supplementation had reductions in C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), and erythrocyte sedimentation rate, which are all markers of inflammation.
In their discussion of the findings, authors Aya Mousa and Barbora de Courten at Monash University observe that low grade inflammation coexists with and precedes the development of diabetes. While obesity reduction through lifestyle modification is the front-line treatment for preventing the progression of type 2 diabetes, efforts are often hindered by low adherence and poor sustainability. "If vitamin D supplementation can improve inflammatory marker levels, as shown here, there may be important benefits for patients with type 2 diabetes, given that elevated cytokines promote insulin resistance, dyslipidemia, and atherosclerosis," they write.
"This is the first systematic review and meta-analysis of randomized clinical trials investigating the effects of vitamin D supplementation on inflammatory markers in type 2 diabetes," they announce. "This meta-analysis suggests that vitamin D supplementation may be a beneficial adjunct therapy to reduce subclinical inflammation in patients with type 2 diabetes, potentially preventing or delaying disease progression."