The major function of Vitamin D3 is the maintenance of blood serum concentrations of calcium and phosphorus by enhancing absorption of these minerals in the small intestine. Vitamin D deficiency can lead to abnormalities in calcium and bone metabolism such as rickets in children or osteomalacia in adults. More recent research has linked adequate vitamin D3 to support other health issues including: cardiovascular health, muscle aches, normal blood sugar levels, immunity, mood, mental health, gum health and skin health.
Details: Vitamin D3
Why do we need it for health?
Vitamin D is really less of a vitamin and more of a hormone precursor. Its actions are more global and hormonal in nature than other vitamins. The major biological functions of Vitamin D are to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones, providing protection from osteoporosis and fracture. For this reason, severe Vitamin D deficiency causes rickets in children and osteomalacia in adults.
Vitamin D is associated with immune function. Activated Vitamin D in the adrenal gland regulates tyrosine hydroxylase, necessary for the production of dopamine, epinephrine and norepinephrine. These neurotransmitters affect mood, drive, ambition, and an overall feeling of well being which may explain why people in the northern climates get S.A.D. (Seasonal Affective Disorder). Vitamin D intake affects improvements in energy and mood. Healthy Vitamin D levels also control leptin secretion by fat cells, which helps maintain normal weight and fat storage.
How can we get it in the diet?
Vitamin D is found in many dietary sources such as fish, eggs, fortified milk, and cod liver oil. Exposure to the sun causes Vitamin D to be produced in the skin. It is then further activated in the liver and kidneys.
Why would we be deficient?
Current recommendations to avoid all sun exposure are causing a substantial decrease of Vitamin D synthesis in the skin. The application of sunscreen with an SPF factor of 8 reduces production of vitamin D by 95%. Without this critical sun exposure, we cannot form the Vitamin D required to keep us healthy. Foods such as milk, which are fortified with Vitamin D usually contain Vitamin D2 which is much less effective than D3. People with even higher risk for Vitamin D deficiency include the elderly, the obese, people with dark skin and individuals who have fat malabsorption syndromes (e.g., cystic fibrosis and cholestatic liver disease) or inflammatory bowel disease (e.g., Crohn's disease). Many of us are chronically low and require supplementation.
What about supplementing with it?
The term "Vitamin D" refers to several different forms of this vitamin: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D3 is always the preferred choice. The inefficiency of vitamin D2 compared with vitamin D3, is now well documented, and no successful clinical trials to date have shown that vitamin D2 prevents fractures.
(Vitamin D3 should be considered for anyone requiring calcium supplementation for bone health as the two together are much more effective than either alone. We have simplified this equation with our own Calcium Plus, and recommend it freely for bone health, mood stabilization, immune health, and muscle function and recovery.)