Effect of oral vitamin D supplementation on blood glucose levels in adults with Type 2 Diabetes Mellitus in the Middle Eastern region: A systematic review

Abstract

Introduction: Type 2 diabetes mellitus is one of the most complex diseases of the present era. Studies are still investigating effective ways to reduce episodes of hyperglycaemia in diabetic patients. One of the most controversial means of influencing glucose levels introduced in the last decade is vitamin D supplementation. The results of studies have varied between supporting the use of vitamin D supplements as an adjunct treatment to lower blood glucose levels and opposing it for lack of sufficient evidence. The Middle East has high rates of both diabetes and vitamin D deficiency. The aim of this systematic review is to investigate the role of oral vitamin D supplementation on blood glucose levels in patients with type 2 diabetes in the Middle East. Methods: The Cochrane Library, PubMed, Medline, and NUsearch were searched for studies published from 2011 to 2021. RCTs were selected to examine the effect of oral vitamin D supplementation on glucose levels in patients with type 2 diabetes. Inclusion criteria included adult patients over 18 years of age in Middle Eastern countries. The Cochrane Collaboration's tool was used to assess the quality of the study. Results: Eight studies were included in this systematic review. The use of oral vitamin D supplementation of up to 50,000 IU weekly for eight weeks was associated with positive results in lowering glucose levels in overweight or obese diabetic patients after serum 25(OH)D levels increased above 20 ng/mL. Conclusions: vitamin D supplementation provided beneficial effects in patients with both obesity or overweight and type 2 diabetes, in conjunction with vitamin D deficiency.