Vitamin D is a group of fat-soluble prohormones, which supports the absorption and metabolism of calcium and phosphorous. There are five known forms of vitamin D: vitamin D1, D2, D3, D4, D5. However, only vitamins D2, also known as ergocalciferol, and D3, also known as cholecalciferol, are significant to humans’ health and metabolism.
Sources of vitamin D
Humans are obtaining the vitamin D from sun exposure, food and supplements. Dietary sources such as fish, eggs, fortified milk, and cod liver oil are especially rich in vitamin D. Only 10 minutes of daily sunlight, exposure is also sufficient to prevent vitamin D deficiency. This vitamin is biologically inert and has to undergo certain reactions to become active in the body. Vitamin D is converted in the liver into the phormone calcidiol, which is then converted into calcitriol – biologically active form of vitamin D.
Benefits of vitamin D
The main purpose of vitamin D in human’s health is to support normal blood levels of calcium and phosphorus. Vitamin D is essential in the process of absorption of calcium and it contributes to overall skeletal strength. Vitamin D may thus prevent osteoporosis, but it also plays a significant role in defending the body against microbial invaders. Vitamin D also modulates neuromuscular function, reduces inflammation, and may protect against hypertension, cancer and certain autoimmune diseases like multiple sclerosis.
Vitamin D deficiency
Certain groups of population are more prone to developing vitamin D deficiency. Elderly population, obese people, exclusively breastfed infants and people with limited sun exposure are at the highest risk. Some medical conditions such as fat malabsorption syndromes and inflammatory bowel diseases are also associated with vitamin D deficiency. Low levels of vitamin D are usually caused by inadequate exposure to sunlight, insufficient foods intake, disorders in the gastrointestinal tract, liver disorders, kidney disorders and rarely some hereditary disorders.
Low levels of vitamin D can usually lead to rickets and osteomalacia. Rickets is a disease that generally affects children, causing the abnormal bone formation. Low levels of vitamin D are affecting the ability to mineralize bones, and the bones are becoming soft and distorted. Osteomalacia has a similar effect on the skeletal system. It is the softening of the bones caused by loss of mineral, especially calcium, from the bones. This health problem affects only adults.
Treatment of vitamin D deficiency
To restore optimum levels of vitamin D, people should try to increase the supply of minerals in the daily diet. Good sources of vitamin D are milk, orange juice, some fortified soy beverages, cooked trout, tuna, salmon, eel or mackerel, beef liver, and eggs. The easiest way to restore sufficient levels of vitamin D is to have enough sun exposure every day. The ultraviolet rays essential for vitamin D synthesis do not pass through normal window glass. It is important to spend at least 10 minutes outside every day, enjoy the fresh air and beneficial sunlight.