Vitamin D Supplements & Foods
What Is Vitamin D?
Vitamin D, often referred to as the “sunshine vitamin,” is actually a fat-soluble hormone that the body can synthesize naturally. There are several forms, including two that are important to humans: D2 and D3. Vitamin D2 (ergocalciferol) is synthesized by plants, and vitamin D3 (cholecalciferol) is synthesized by humans when skin is exposed to ultraviolet-B (UVB) rays from sunlight. The active form of the vitamin is calcitriol, synthesized from either D2 or D3 in the kidneys. Vitamin D helps to maintain normal blood levels of calcium and phosphorus.
Why Is Vitamin D Necessary?
Vitamin D assists in the absorption of calcium and promotes bone mineralization, which may prevent or slow the progression of osteoporosis. It also helps to strengthen the immune system and protect against a number of serious diseases, including rickets and osteomalacia. Research suggests vitamin D may also provide protection from hypertension, psoriasis, several autoimmune diseases (including multiple sclerosis and rheumatoid arthritis), and reduce the incidence of fractured bones. In addition, growing evidence has demonstrated its important role in defending against cancer (studies link a deficiency of vitamin D to as many as 18 different cancers).
What Are The Signs Of A Deficiency?
Deficiencies of vitamin D are common, especially in industrialized countries in northern latitudes, where sun exposure is typically infrequent. Low levels of vitamin D may be indicated by porous bones, weak muscles and easy fracturing.