Vitamin D is also known as "fat-soluble factor D". It is also known as Calciferol as it is established that it promotes deposition of calcium in the bones and is important for skeletal growth and strong bones.
There are two main types of vitamin D. Ergosterolate is the basic building block of vitamin D in plants, cholesterol is the basic building block of vitamin D in humans. In case of ultraviolet light from the sun on the leaves of plants, the ergosterolate becomes ergocalciferol or vitamin D2. Similarly, when ultraviolet light affects the skin cells, a form of cholesterol they called 7-dehydrocholesterol is converted into cholecalciferol - a form of vitamin D3.
Basic functions of vitamin D
- Maintaining adequate levels of blood calcium. Although commonly classified as a fat-soluble vitamin, vitamin D actually functions as a hormone. Calcitriol, the most metabolically active form of vitamin D, works with the parathyroid hormone (PTH), to maintain proper calcium levels in the blood.
- Maintaining adequate levels of phosphorus in the blood. When vitamin D levels remain lower, parathyroid glands become overactive - a condition known as hyperparathyroidism. In this condition, parathyroid hormone levels rise and fall of phosphorus. Without adequate amounts of phosphorus, bone can not be properly mineralized, which contributes to defects in both osteomalacia. In addition, new bone cells, defined as osteoblasts (cells that create new bone) absorb more water and swell, causing bone pain associated with osteomalacia.
- Maintenance of normal cell growth and function. The body converts vitamin D into calcitriol not only in the kidney but also in other tissues, such as lymph glands, and skin. Because Calcitriol is very closely related to cell function and growth, it follows that vitamin D may be important in the prevention and treatment of certain tumors.
Vitamin D may also play a role in regulating cell growth and function in brain cells. It is also associated with maintaining a healthy immune function and prevent excessive inflammation.
Vitamin D deficiency
Vitamin D deficiency leads to decreased absorption of calcium and phosphorus. As a result, prolonged vitamin D deficiency has a negative effect on bone mineralization. In infants and children, this deficiency manifests as rickets - a condition characterized by bone deformities and growth retardation. Older people with vitamin D deficiency may experience bone pain and osteomalacia (soft bones).
Periodontal disease, a chronic inflammatory gum disease common in people over 50 years, is another example of a lack of vitamin D. Vitamin D and its anti-inflammatory effects were observed in a wide range of diseases, including hypertension, diabetes mellitus type 1 and psoriasis.
Of particular importance for people with limited sun exposure, is to include good sources of vitamin D in their diets.
Overdose of vitamin D
Excessive dietary intake of vitamin D can be toxic. Symptoms of toxicity include loss of appetite, nausea, vomiting, high blood pressure, kidney failure. For this reason the upper limit for vitamin D is as follows: baby 0-12 months, 25 micrograms per day, children and adults, 50 micrograms per day, pregnant and lactating women 50 micrograms per day.
Vitamin D is a stable compound. Neither cooking nor long-term storage can significantly reduce levels of vitamin D in food. The following drugs affect the absorption, utilization and/or activation of vitamin D: anticonvulsant drugs, medicines, isolating bile acid drugs used to lower cholesterol levels, Cimetidine, hormone replacement therapy, corticosteroids, heparin and others.
Benefits of Vitamin D
Vitamin D may play a role in the prevention and/or treatment of the following diseases : atherosclerosis, breast cancer, colon cancer, ovarian cancer, depression, epilepsy, hypertension, inflammatory bowel disease, kidney disease, liver disease, multiple sclerosis, osteoporosis, periodontal disease, psoriasis, tinnitus and more.
Both forms of vitamin D are used in dietary supplements, this applies to ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).