Vitamin D is the only essential nutrient that your body does not obtain from food. Instead, the sun is the source your body relies upon to obtain this vitamin. Though vitamin D is present in certain cold-water fish, its scarcity in foods has made fortification of commonly eaten foods, most notably milk, necessary to prevent deficiencies. Vitamin D supports a variety of important health functions.
Bones and Teeth
In the normal bone-maintenance process, certain bone cells break down old bone tissue while other cells replace the old bone with new bone. While vitamin D is often thought of as a bone-building vitamin, it actually stimulates activity of cells that break bone down, which then leads to activation of the building up process, according to a study published in the 2004 issue of the "Proceedings of the Japan Academy, Series B." Vitamin D also supports your blood levels of calcium and phosphorus by promoting absorption of these minerals, making them available for your body to use to build strong bones and teeth.
Vitamin D may contribute to muscle mass and strength, according to a study published in the 2011 issue of the "Journal of Bone and Mineral Research." In the study of adults ages 21 to 97 years old, researchers compared muscle mass to vitamin D status and found that those younger than 65 years of age who had low vitamin D levels also had low muscle mass. Its role in muscle function might be to promote accumulation of phosphorus, a mineral your muscles require for proper metabolism. Vitamin D also prevents muscles from atrophy, stimulates protein synthesis and increases the numbers of fast-twitch muscle fibers. One of the symptoms of a vitamin D deficiency is muscle weakness.
Several types of white blood cells contain receptors for vitamin D, and vitamin D regulates the growth and function of these cells, according to Gerald Litwack, editor of the book "Vitamins and the Immune System." As such, vitamin D may be helpful in prevention and management of both infectious diseases, such as tuberculosis, and certain autoimmune diseases, such as type 1 diabetes and multiple sclerosis. Children and young adults of vitamin D-deficient mothers tend to have higher rates of these autoimmune conditions.
Cancer prevention is one of the roles of vitamin D, according to researchers at the University of Miami School of Medicine. Vitamin D inhibits uncontrolled cell reproduction of prostate cancer and head and neck cancers, in part, by helping to maintain healthy communication between cells, thereby ensuring healthy cell reproduction. Where vitamin D levels are adequate, cells stick together better, allowing for better intercellular communication. In vitamin D deficiency, cells lose this ability and may revert back to more immature forms, which can lead to cancer development.
- Japan Science and Technology Information Aggregator, Electronic: How Does Vitamin D Regulate Bone Formation and Resorption?
- University of Chicago Hospitals: Vitamin D
- Journal of Bone and Mineral Research: Is Vitamin D a Determinant of Muscle Mass and Strength?
- Dark Deception; Discover the Truths About the Benefits of Sunlight Exposure; Joseph Mercola
- Vitamins and the Immune System; Gerald Litwack
- University of Miami Miller School of Medicine: Vitamin D Inhibits Cancer Cell Proliferation Through Nuclear Exclusion and Decreased Activity of Cyclin-Dependent Kinase 2
- University of California San Diego News Center: New Model Suggests Role of Low Vitamin D in Cancer Development
- young boy showing his muscles image by Ramona smiers from Fotolia.com