Vitamin D is the most important fat soluble Vitamin that is essential for the human body.Vitamin D is a group of fat-soluble secosteroids, the two major physiologically relevant forms of which are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D is carried in our human blood stream to the liver, where it is converted into the Prohormone calcidiol. Circulating calcidiol may then be converted into calcitiol, which is the biologically active form of Vitamin D. Either in the kidneys or by monocyte-macrophages in the immune system. When synthesized by monocyte-macrophages, calcitriol acts locally as a cytokine, defending the body against microbial invaders. Vitamin D helps an individual stay healthy and aids in absorption of other nutrients.
Over the last few hundred years human lifestyles have changed. The industrial revolution resulted in more indoor work and less exposure to sunlight. Many societies around the world wore more clothing over the centuries, further reducing skin exposure to sunlight. These changes have brought with them a significant reduction in the natural production of vitamin D and subsequent diseases.
Five forms of vitamin D have been discovered, vitamin D1, D2, D3, D4, D5. The two forms that seem to matter to humans the most are vitamins D2 (ergocalciferol) and D3 (cholecalciferol).
Vitamin D is often added to foods and is also available in supplement form. The body is able to make vitamin D itself when the skin is exposed to the ultraviolet rays of sunlight. While excessive exposure to sun can be dangerous, a little can actually be beneficial. Vitamin D plays multiple roles in the human body.
Vitamin D is important for Calcium Absorption
Vitamin D Reduces the Risk of Osteoporosis
Vitamin D reduces risk of certain cancers
Humans attain vitamin D from exposure to sunlight, diet and supplements. Vitamin D deficiency is common in children and adults. In utero and childhood, vitamin D deficiency may cause growth retardation, skeletal deformities and increase risk of hip fractures later in life. With out Vitamin D, the human Body will not be able to properly absorb calcium within the gut. Vitamin D and calcium are partners in helping to keep bones strong and healthy, and needed by children to ensure bones grow properly.
Osteoporosis is a condition in which the bones of the body become weak and thin and that causes bones to break easily. Not having enough vitamin D in the body can contribute to the development of osteoporosis because a lack of vitamin D means less calcium absorption. Adequate amounts of vitamin D in the body may reduce the risk of an individual developing colon cancer. Vitamin D appears to have a protective characteristic in regards to the cancer. Vitamin D can reduce the risk of an individual developing prostate or breast cancers.
Vitamin D also works in concert with a number of other vitamins, minerals, and hormones to promote bone mineralization. Research also suggests that vitamin D is important to maintain a healthy immune system, regulate cell growth, and prevent cancer. Vitamin D has been shown to protect against the development of autoimmune disease such as inflammatory bowel disease, multiple sclerosis, and rheumatoid arthritis. It also has been shown to be helpful in decreasing disease severity for those suffering with autoimmune disease.
Sun exposure is perhaps the most important source of vitamin D because exposure to sunlight provides most humans with their vitamin D requirement. The further you live from the equator, the longer you need to be exposed to the sun in order to generate vitamin D. It is extremely important for individuals with limited sun exposure to ingest supplemental vitamin D.
Natural sources of vitamin D
Fatty fish species, such as Catfish, Salmon, Mackerel, Sardines, Tuna, egg, Beef liver,Fish liver oils, such as cod liver oil, Mushrooms are the only vegan source of vitamin D besides UV light or sunlight exposure. Food sources such as fatty fish, eggs, and meat are rich in vitamin D and are often recommended for consumption to those suffering with vitamin D deficiencies.
Risk of Having Too Much of Vitamin D
Inspite of many benefits of having adequate amounts of vitamin D in the human body, Too Much can be toxic. Symptoms like nausea, weight loss, vomiting and feeling weak may appear due to excess intake of Vitamin D. More serious symptoms may include mental confusion and irregular heartbeat because too much vitamin D can also raise calcium levels too high. Kidney stones which consist of hardened calcium rocks can also be caused by too much intake of vitamin D in the body.
Even though vitamin D is important for the proper functioning of the human body, supplementing with over-the-counter pills may not be necessary unless advised by a physician. A healthy diet with plenty of vitamin D enriched foods such as milk and yogurt, and short term exposure to sunshine on a regular basis will usually provide an adequate amount of vitamin D.