Vitamin D

What is Vitamin D?

You produce vitamin D mainly under the influence of sunlight on your skin. It works throughout your body, from bones to immune system. A healthy value supports your bones, muscles and resistance. In our regions a shortage in winter is very common.

Clinical frame

25-hydroxyvitamin D or 25(OH)D is the main marker of vitamin D status and reflects the reserve built up over the past weeks. Vitamin D plays a central role in calcium balance and is essential for normal bone and muscle function ^[3].

A deficiency can lead to reduced calcium absorption, muscle weakness and bone demineralisation ^[2]. There is, however, no full international consensus on the optimal target value, especially for values between 20 and 30 ng/mL ^[3].

Low vitamin D values are also associated with insulin resistance and cardiometabolic dysregulation, but a causal link has not been sufficiently demonstrated ^[1]. Correcting a deficiency is therefore the main goal; aiming for higher values offers no proven additional benefit ^[2].

What moves this value?

Little daylight, the winter months, covered skin and getting older lower production. Your skin type also plays a part.

Regular daylight and, especially in winter, a supplement bring this up to level slowly but reliably. Discuss the right amount with your doctor.

References

1. Lei, X. et al. Serum and supplemental vitamin D levels and insulin resistance in T2DM populations: a meta-analysis and systematic review. Scientific Reports 13, 12343 (2023). doi.org/10.1038/s41598-023-39469-9
2. Rebelos, E. et al. The Role of Vitamin D in Health and Disease: A Narrative Review on the Mechanisms Linking Vitamin D with Disease and the Effects of Supplementation. Drugs 83, 665–685 (2023). doi.org/10.1007/s40265-023-01875-8
3. Cesareo, R. et al. Clinical Management of Vitamin D Deficiency in Adults. Nutrients 10, 546 (2018). doi.org/10.3390/nu10050546