The Essentials of Vitamin D

Studies have shown that vitamin D intake reduces the chances of colon, breast and prostate cancer. In addition vitamin D helps maintain strong bones. Older adults can reduce their risks of falls by more than 20% by ensuring that they get enough vitamin D. A study recently reported in Journal of the American Medical Association noted that vitamin D may also improve muscle strength, thereby reducing fracture risk from falls.


Scientist are finding that when we avoid sunlight all the time by slathering ourselves with sunscreen to avoid the increased skin cancer risk from sun overexposure, or avoiding the outdoors altogether through an indoor sedentary lifestyle, we lose our most effective source of vitamin D. Our bodies make vitamin D when skin is exposed to sunlight. This does not mean that you have to be out in sun all the time, or lying out in the beach tanning. All you have to do is to expose your skin to sun for 10 minutes in summer and 15 minutes in winter.

Blood levels of vitamin D are low in one in five women living in America and North Europe. Post-menopausal women also get too little dietary calcium. But the former deficiency may be more important that the latter. In fact the recent studies suggest that higher than RDA (Recommended Dietary Allowances) of vitamin D may be more important than RDA intake of calcium to bone health.
There is actually a tightly intertwined connection between vitamin D, calcium and lesser known substance called parathyroid (PTH). PTH regulates the amount of calcium in the bloodstream. When the level of calcium is low in blood , the thyroid gland secrets more PTH, which raises the level of calcium by taking it from the bone. If the pattern continues, bones will eventually become brittle and prone to more breakage.
High level of Vitamin D in blood inhibits the secretion of PTH, thereby preventing the loss of calcium from the bones. Conversely, low vitamin D level prompts loss of calcium from the bones and raises the risks of osteoporosis and fractures. This is one reason why most experts say the RDA for Vitamin D, which is 400 international units per day, is too low and should be increased to 600 to 800 international units per day.
The Food and Nutrition Board of Institute of Medicine of US National Academy of Science has recommended the following adequate daily intakes (AI) for vitamin D.


Infants, children and adults up to 50 years of age (includes pregnant and nursing women): 5.0 micrograms (200IU)
Men and women 51-70 years: 10.0 micrograms (400 IU)
Men and women older than 70 years: 15.0 micrograms (600 IU)
Studies have also shown that consumption of more than 800 milligrams of calcium per day may be unnecessary for bone health if there is enough vitamin D. Sufficient vitamin D levels an can ensure an ideal level of PTH, even when calcium intake is lower.

A few sources Vitamin D are cod liver oil, cheese, egg yolks, cream, fortified milk, margarine, oysters, fish, and butter. Get it from sunlight. A good solution is to spend fifteen minutes in the sun and then apply your sunscreen.