Vitamin D is a unique vitamin because the body synthesizes it when the skin is exposed to ultraviolet B (UVB) rays from the sun.
This fat soluble vitamin can also be obtained from eating sardines, salmon, tuna, mackerel and other oily fish, as well as by taking fish liver oils. Egg yolks, beef liver, and dairy products like cheese also contain some vitamin D.
Vitamin D is vital for bone health because it helps the body absorb calcium from the food that is being digested in the intestines. After absorption, vitamin D is still needed by the body to maintain normal levels of this important mineral in the blood.
Vitamin D is also needed by the body to make new bone from the absorbed calcium in a process known as mineralization. Its importance is seen clearly in children who develop rickets when they have vitamin D deficiency. These children have poorly mineralized bones which are soft and unable to bear their weight, and thus they develop bow legs and knock knees.
Adults also need vitamin D to maintain healthy bones since its deficiency causes osteomalacia. This condition, which is also characterized by defective mineralization, results in painful bones which are thin and thus more likely to break.
Middle aged menopausal women also need vitamin D since its deficiency worsens into osteoporosis. The progressive loss of calcium and bone mass in osteoporosis, which results in brittle bones that break easily, can be reduced by Vitamin D.
To prevent these complications of its deficiency, foods which are fortified with vitamin D should be added to the diet. Examples of such foods include fortified orange juice, cereal and milk, which can be taken to start each day.
This increased dietary intake should be combined with basking to help the body make its own vitamin D. This can be done by exposing bare arms and legs, without sunscreen, to the sun for 5 to 10 minutes.
Though the amount of vitamin D made with this method depends on many factors, like the time of the day, the season of the year, cloud cover, skin pigmentation and the amount of sunscreen applied, basking between 10 a.m. and 3 p.m. twice a week can ensure the body has adequate amounts of the sunshine vitamin to make and maintain healthy bones.
Medical Disclaimer: Please consult your doctor regarding questions about Vitamin D and bone health.
Written by: Dr. Marian, Freelance Medical Writer