As we become more aware of health issues people look to supplements to help improve their health. This article and video “Dr. Joe Prendergast on Vitamin D” offers some insights to the pros and cons of Vitamin D. There are additional links below to help you learn more about vitamin D.
Dr Joe Prendergast, M.D. of the Endocrine Metabolic Medical Center speaks on the benefits of Vitamin D.
Duration : 0:8:34
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 without a subscript refers to either D2 or D3 or both. Vitamin D3 is produced in the skin of vertebrates after exposure to ultraviolet B light from the sun or artificial sources, and occurs naturally in a small range of foods. In some countries, staple foods such as milk, flour and margarine are artificially fortified with vitamin D, and it is also available as a supplement in pill form. Food sources such as fatty fish, eggs, and meat are rich in vitamin D and are often recommended for consumption to those suffering vitamin D deficiency. Light-exposed mushrooms may provide up to 100% of the recommended Daily Value of vitamin D.
Vitamin D is carried in the bloodstream to the liver, where it is converted into the prohormone calcidiol. Circulating calcidiol may then be converted into calcitriol, 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.
When synthesized in the kidneys, calcitriol circulates as a hormone, regulating, among other things, the concentration of calcium and phosphate in the bloodstream, promoting the healthy mineralization, growth and remodeling of bone, and the prevention of hypocalcemic tetany. Vitamin D insufficiency can result in thin, brittle, or misshapen bones, while sufficiency prevents rickets in children and osteomalacia in adults, and, together with calcium, helps to protect older adults from osteoporosis. Vitamin D also modulates neuromuscular function, reduces inflammation, and influences the action of many genes that regulate the proliferation, differentiation and apoptosis of cells.
Complex regulatory mechanisms control metabolism and recent epidemiological evidence suggests that there is a narrow range of vitamin D blood levels in which metabolic functions are optimized. Levels above or below this natural homeostasis of vitamin D are associated with increased mortality.