Vitamin D3 known as cholecalciferol. It is also known as sunshine vitamin as it is synthesized in our skin through sunlight.
Physiology– The vitamin D synthesized in our skin by sunlight is in inactive form. It undergoes the hydroxylation process in our body by liver producing 25-OH cholecalciferol by 25-hydroxylase enzyme. Again in kidney the final active form 1,25-OH hydroxycholecalciferol is produced by the enzyme 1-hydroxylase.
Vitamin D3 helps in absorption of calcium in our body. Except that, it has diverse roles in our body. It’s role in diabetes and cardio-vascular diseases are enormous. Vitamin D receptors are also present in pancreatic beta cells. Vitamin D mediates the pancreatic beta cell calcium dependent endopeptidases converting proinsulin to insulin and increasing insulin output.
Dietary Recommended Intake level of Vitamin D3—
Infants —- 400 IU
Children 1-8 years —- 600 IU
Adults —- 600 IU
Pregnant women —- 600 IU
Adult > 70years —- 800 IU
Categorization of vitamin D3 level—
<10 ng/ml — Severe deficiency
10-24 ng/ml — Mild to moderate deficiency
25-80 ng/ml — Normal
>80ng/ml — Toxicity possible
Role of vitamin D3 in diabetes are enormous. According to European society of Endocrinology, those having diabetes, vitamin supplementation for 6 months increases the beta cell sensitivity and slow the deteriorating metabolic function.
Studies in support of link between Vitamin D3 deficiency and Diabetes–
The National Health and Nutrition examination Survey (NHANES) III study between 1988 and 1994 showed a inverse relationship between low levels of 25-OH vitamin D and diabetes prevalence.
An observational study from the Nurses Health Study with 83,779 women with no history diabetes of more than 20 years age found to have increased risk of type 2 diabetes with low levels of vitamin D in body.
According to American diabetic association, observational studies show low level of vitamin D status is associated with type 1 diabetes.
Hypponenon et al study on 10,821 children in Finland shows those who took 2000 IU of vitamin D daily were less likely to develop type 1 diabetes.
Mechanism of vitamin D lowering cardiovascular risk—
1. Vitamin D lowers inflammatory markers like IL-6, IL-10, TNF, PG, CRP
2. Decrease calcium ion cellular influx inhibiting smooth muscle proliferation.
3. Decrease renin and RAAS system thus regulates blood pressure.
4. Increase insulin sensitivity regulating diabetes.
