Vitamin D might a risk factor of insulin resistance, diabetes, obesity, etc. (50 ng) – Oct 2021

Mechanisms Involved in the Relationship between Vitamin D and Insulin Resistance: Impact on Clinical Practice

Nutrients . 2021 Oct 1;13(10):3491. doi: 10.3390/nu13103491.
Victoria Contreras-Bolívar 1 2, Beatriz García-Fontana 1 2 3, Cristina García-Fontana 1 2 3, Manuel Muñoz-Torres 1 2 3 4

 Download the PDF from VitaminDWiki

Recent evidence has revealed anti-inflammatory properties of vitamin D as well as extra-skeletal activity. In this context, vitamin D seems to be involved in infections, autoimmune diseases, cardiometabolic diseases, and cancer development. In recent years, the relationship between vitamin D and insulin resistance has been a topic of growing interest. Low 25-hydroxyvitamin D (25(OH)D) levels appear to be associated with most of the insulin resistance disorders described to date.
In fact, vitamin D deficiency may be one of the factors accelerating the development of insulin resistance. Vitamin D deficiency is a common problem in the population and may be associated with the pathogenesis of diseases related to insulin resistance, such as obesity, diabetes, metabolic syndrome (MS) and polycystic ovary syndrome (PCOS).
An important question is the identification of 25(OH)D levels capable of generating an effect on insulin resistance, glucose metabolism and to decrease the risk of developing insulin resistance related disorders. The benefits of 25(OH)D supplementation/repletion on bone health are well known, and although there is a biological plausibility linking the status of vitamin D and insulin resistance supported by basic and clinical research findings, well-designed randomized clinical trials as well as basic research are necessary to know the molecular pathways involved in this association.
- - - - - -

Unsolved Questions and Conclusions (clipped from PDF)

Diseases associated with insulin resistance are becoming increasingly common. Recent findings suggest that the molecular background to the development of insulin resistance may be related to vitamin D deficiency.
Taken together, the results of basic and clinical studies reveal that vitamin D deficiency may be a key factor triggering the insulin resistance. In this review, a large body of findings on vitamin D and its association with disorders related to insulin resistance such as obesity, T2D, MS, and PCOS has been analyzed, with controversial results. So far, numerous observational studies and randomized trials involving very heterogeneous populations have been conducted, differing in design, duration, and in the types and doses of vitamin D.

In addition, there are factors, such as glutathione deficiency, which could play a role in the action of vitamin D on insulin resistance. This review highlights the need to clarify the level of vitamin D required to obtain a tangible benefit, if any. This concentration is probably higher than the current recommendations focused mainly on achieving bone metabolism benefits. Although currently there is no consensus as to whether vitamin D supplementation is needed in the general population to improve health outcomes, vitamin D supplementation at doses approaching 600-4000 IU/day could be an option to increase 25(OH)D levelsclose to 50 ng/mL to improve insulin resistance and the associated disorders.
Establishing whether specific populations such as those with obesity, MS, prediabetes, T2D, and/or PCOS could benefit significantly from nutritional recommendations regarding vitamin D intake has become a matter of particular interest. However, what does seem to be clear is the need to determine the level of 25(OH)D in high-risk subjects and to supplement in case of deficiency, which will undoubtedly bring a benefit and provide more data to draw more solid conclusions.