Despite what its name suggests, vitamin D is a steroid hormone. Vitamin D resembles other, more well-known hormones such as testosterone and oestrogen. Vitamin D has a major impact on human health as this hormone affects hundreds of genes in the majority of cells in the body.
The best way of forming vitamin D in the body is to expose the skin to sunlight. For this reason, many people in Nordic countries have problems with vitamin D levels in winter as there are not many hours of sun in these countries. As a result, many people suffer from deficiencies and so take vitamin D in the form of a dietary supplement.
Vitamin D deficiency causes many disorders such as depression, diabetes, cancer, heart disease, general aches and pains and more. Therefore, it is important to analyse your vitamin D level as this vitamin plays such an enormous part in the body's metabolism.
High levels seen in cases of hyperparathyroidism, in people with high levels of vitamin D intake, cases of sarcoidosis and other granulomatous diseases with increased calcium concentration, and frequently during pregnancy. Toxic levels (>approx. 350 nmol/L) are particularly common in people who take vitamin concentrates (AFI-D2 Forte). This may result in hypercalcaemia and metastatic calcification of the soft tissues. The half life is considered to be 2 to 3 weeks, while the terminal half life is considerably longer.
A low level may also be due to reduced conversion of vitamin D in the skin, and it is common for levels to fall below the reference limits in winter. Hypoparathyroidism may also cause low levels. An increase in clinical manifestations of vitamin D deficiency has been seen in immigrant families in particular.