How Sunshine Vitamin D helps to reduce the risk of diabetes


In normal the body converts carbohydrates from your foods convert to blood glucose. Insulin a hormone produced by beta cells of the pancreatic islets that allows glucose from blood to enter cells of the body. And your body uses that glucose for producing energy.  In the development of diabetes your pancreatic cells either can’t produce insulin or your cells of the body can’t use insulin. In such conditions you blood glucose level become high. And on the other hand vitamin d deficiency is also common in diabetes. Researchers have shown much interested in finding the roles of vitamin d in diabetes. Can vitamin be used in prevention as well as treatment in diabetes? If can, how Sunshine Vitamin D helps to reduce the risk of diabetes. How they are connected with?

How Sunshine Vitamin D helps to reduce the risk of diabetes

Vitamin D actually works like a hormone so many calls vitamin D as hormone rather than a vitamin. The active from of vitamin D or calcitriol or 1,25(OH)2D bind with VDR or Vitamin D Receptor which encodes the nuclear hormone receptor. The perception on vitamin D on its influence of human health has changed after discovering vitamin D receptor (VDR) and the vitamin D activating enzyme 1-α-hydroxylase are expressed in many cell types. 

It is a well-known clinical observation that inflammatory diseases are accompanied by metabolic complications like high blood sugar, insulin resistance and fat metabolism. Obesity as well as diabetes, both are also associated with chronic inflammation which makes further complications including heart disease. And vitamin D plays an important role in carbohydrate, lipid metabolism, inflammation as well as autoimmunity. (1)

Type 1 Diabetes

Type 1 diabetes an autoimmune disease develops due to malfunctioning of body’s own immune system characterized by the chronic inflammation of the pancreatic islets. As that result immune cells destroy insulin producing beta cells of pancreas. Due to which pancreas is unable to produce insulin which carries blood glucose to cells of the body. So in absence of insulin you blood glucose becomes high.

How vitamin D helps in prevention of Type 1 diabetes

In addition to other effects vitamin D decreases metabolic syndrome, inflammation and also autoimmunity.(1) The active form of vitamin D i.e. 1,25(OH)2D binds to the nuclear vitamin D receptor (VDR), which acts on the vitamin D response element (VDRE) of target genes to exert its effects. (2)

Researchers from the Cellular Therapy of Diabetes, Institut National de la Santé et de la Recherche Médicale, France provided additional evidence that active form of vitamin D protects beta cells of pancreatic islets. (3) Study published in the journal Cell in 2018 researchers also found the vitamin D receptor (VDR) as a key modulator of inflammation and protection of beta cells.(4)

Study on link between vitamin D deficiency and type 1 diabetes

Earlier study vitamin D deficiency exhibited reduction in insulin secretion. They had also indicated important role of active form of vitamin D in the endocrine functioning of the pancreas. (5)

How Sunshine Vitamin D helps to reduce the risk of diabetes

If you have diabetes whether type 1 or type 2 you could also have diabetic retinopathy, a condition that affects eyes. Study on 75 young Japanese with type 1 diabetic, researchers found vitamin D deficiency were independent determinants of diabetic retinopathy.(6) Other studies also showed that patients with type 1 diabetes had significantly lower vitamin D levels. Vitamin D deficiency influence the progression of the disease from pre-diabetes to diabetes. According to scientists. “Vitamin D deficiency precedes the onset of type 1 diabetes“. (7)

Evidence on preventing type 1 diabetes

A study had included 10821 children born in 1966 in northern Finland. Researchers collected data about frequency as well as dose of vitamin D supplementation during the first year of life. Then they followed these children for 31 year. Surprisingly they discovered children who received recommended dose of vitamin D supplementation during 1st year of their life had around 80% reduction in the risk of development of type 1 diabetes compared to who received less than the recommended amount. (8)

In a study on 80 patients with type 1 diabetes were supplemented with 4000 IU of vitamin D3 and 1200 mg calcium per day. After 12 weeks follow up they concluded that vitamin D repletion improve improve blood glucose level in type 1 diabetes. (9)In an another study published in the journal of Diabetes researchers followed 8676 children before age 4 months at increased genetic risk of type 1 diabetes at 6 sites in the US and Europe. In conclusion, this study also indicated that higher concentration of circulating vitamin D in combination with VDR, may decrease risk of type 1 diabetes in children. (10)

Related article: with cross breeding milk components of cow milk has been changed. And some of such milk increases risk of development of type 1 diabetes.

Other articles on vitamin D series

How vitamin D deficiency can lead to chronic fatigue and also body pain.

Impact of vitamin D in immune system as well as auto immune diseases.

Type 2 diabetes

If you have type 2 diabetes cells of your body does not use insulin properly. This is called insulin resistance. At first, your pancreas produces extra insulin to make up for it. But, over time it can’t able to make up the demand due to increasing insulin resistance and can’t make enough insulin to keep your blood glucose at normal levels. At this point your blood glucose level becomes high and you may experience symptoms of diabetes. And you may not aware initially about the earlier development.

How vitamin D helps in prevention of Type 2 diabetes

A primary cause of disease progression in type 2 diabetes includes beta cell dysfunction due to inflammatory stress and insulin resistance. And so it can lead to impairment of carbohydrate metabolism. Vitamin D receptor (VDR) modulates inflammation as well as involves in protection of beta cells.

Apart from immune modulation and lowering chronic inflammation, vivo and vitro studies have proposed potential roles of vitamin D in glucose metabolism. That includes stimulating insulin secretion via the vitamin D receptor on pancreatic beta cells; and reducing peripheral insulin resistance through vitamin D receptors in the muscles and liver.(11) Presence of vitamin D receptor in pancreatic beta cells lead to think influence presence of vitamin D may help in well functioning of beta cells. In animal study removing vitamin D receptor results impaired the insulin production.(12)

Moreover calcium involves in stimulation of insulin release to the blood. Vitamin D has crucial part in regulation of calcium. And thus low vitamin D level may influence the release of insulin.(13)

Study of vitamin D on type 2 diabetes

Earlier observational studies had found strong co-relation between low vitamin D level with increased risk diabetes. A meta analysis of total of 21 prospective studies involving 76,220 participants and 4,996 incident type 2 diabetes was published in the journal of Diabetes Care in 2013. Researchers found that higher circulating vitamin D levels were monotonically associated with a lower diabetes risk. They also mentioned that this inverse association did not differ by sex, duration of follow-up, study sample size, diabetes diagnostic criteria, or 25(OH)D assay method.(14)

Several other studies had also found inverse relation in between vitamin d deficiency and diabetes and indicated supplementation can contribute to beneficial effect. (15, 16, 17, 18)

However despite of promising results in longitudinal observational studies some studies had not found beneficial co-relation between vitamin d intake and diabetes. (19, 20, 21)

Later Development

A systematic review and meta-analysis had included 24 RCTs to determine the efficacy of vitamin D supplementation on blood glucose and insulin sensitivity in diabetic patients. The study was published in The Journal of Clinical Endocrinology & Metabolism, in September 2017. This unique meta-analysis was comprised of well-designed clinical trials centered on diabetic patients from diverse countries with high prevalence of vitamin D deficiency and poorly controlled type 2 diabetes.

In finding researchers concluded that vitamin D supplementation, a minimum dose of 100 µg/d (4000 IU/day), may significantly reduce serum fasting plasma glucose, blood glucose level, and insulin resistance in homeostatic model. And also helps to control glycemic response and improve insulin sensitivity in type 2 diabetic patients. Homeostasis Model Assessment may constitute a useful method not only for diagnosing insulin resistance but also for follow-up during the treatment of patients with type 2 diabetes.

They also indicated that the lack of appropriate evidence for the beneficial effects of vitamin D might be attributed to several factors. That includes not using optimal dose, short duration of supplementation, small sample size and also conditions like obesity. Obesity is associated with low-grade inflammation leading to insulin resistance and also metabolic disorders such as diabetes. Several studies had reported that vitamin D improves insulin sensitivity and decreases inflammation. Obese individuals are more likely to be vitamin D deficient, and also need two to three times higher doses of vitamin D supplementation for repletion. (22)

Some more results

Another high quality meta analysis of Controlled Trials published in English from inception to September 2017 as published in 2018 in the journal of Nutrients found vitamin D supplementation had shown to reduce insulin resistance effectively. This effect was especially prominent when vitamin D was given in large doses and for a short period of time, and to patients who were non-obese, Middle Eastern, vitamin D deficient, or with optimal glycemic control. (11)

A 2018 published meta-analysis was conducted of 28 randomized clinical trials representing 3848 participants studying glycemic control in prediabetics. Researchers found Vitamin D supplementation and improved vitamin D level had also improved glucose level and insulin sensitivity. They also concluded that vitamin D may be useful as part of a preventive strategy for type 2 diabetes.(23)

Vitamin D with calcium

Another Systematic Review and Meta-Analysis published in the Journal of Clinical Endocrinology & Metabolism concluded vitamin D and calcium deficiency negatively affects blood glucose level. And so combined supplementation of both can improve glucose metabolism in patients of type 2 diabetes. (24)

Here I wish to mention that without vitamin K2, vitamin D and calcium can’t improve bone health. Without K2 calcium begins to deposits in artery rather than bones and teeth. And thus leads to narrowing artery as well as leads to heart disease. Hence adding vitamin K2 is a must.

Bottom Line

Our modern indoor lifestyle with less exposure to sunlight as well as limited food source are making vitamin d deficiency as common. Vitamin D deficiency is also common in diabetes. And so optimum level of same may help in prevention and improvement of diabetes. Hence it makes sense to test vitamin D level in diabetic patients. Moreover long term hospitalization and ICU treatment can also lead to vitamin d deficiency if not supplemented. Vitamin D is a very crucial nutrients that works like hormone rather than a vitamin. Vitamin D participates in many important functions related to your health. Therefore deficiency of which can lead to multiple health complications. So it is a better choice to keep updated.

For dose, safety measure, proper test, best form etc you can read our previous article how vitamin D deficiency is linked with osteoporosis, chronic fatigue and body aches

Disclaimer: Information provided here are generalized information for 
educational purpose only, not intended to provide one to one health
consultation or replace practice of a qualified practitioner. Different
people may have different health condition and may have different reaction
to the same food. Hence it has been advised to consult with health care
provider before application of any of above guidelines.
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Bikramjit Konwar

Author: Bikramjit Konwar


2 Responses

  1. Very informative post. Beneficial effects of vitamin D most of us are not even aware about. No wonder diabetes is becoming so prevalent. One of the reasons apart from bad diet and sedentary lifestyle, could be not getting enough sunlight.

    1. There are many things we don’t know, it’s my little effort to bring to the light

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