This and other vitamins need to be taken over long periods of time. This is an anti-oxidant with activity as a free radical scavenger. Populations with high blood selenium levels are found to have lower death rates due to cancer. Mormons have high selenium blood levels perhaps related to their diet. Cancer patients have low selenium blood levels.
Calcium is deficient in most of our diets.
This deficiency is most prevalent in women who have had children and have never supplemented their own diets with calcium. Calcium consumption along with exercise is the best means to prevent calcium deficiency. Once calcium is lost and signs of osteopenia develop the medical problem may be hard to reverse. Collapse of bone and fractures commonly of the pelvis may occur in such individuals. Bone density studies will detect patients having osteopenia.