Osteoporosis is a thinning and weakening of the bones that can result in bone fractures and disabling breaks. It is a health problem for 44 million Americans (more than half of those over 50).
Here is a link to an interesting summary on the current research on osteoporosis by Dr. Sciabbarrassi. What You Don't Know About Osteoporosis. A quick summary:
Calcium -- either dietary or supplement sources - by itself does not offer any clear or consistent benefit in preventing osteoporosis or reducing fracture risk in anyone.
He also notes that increased dairy intake doesn't help! And that Vitamin D deficiency is a world-wide epidemic. However, the combination of Vitamin D and Calicium is recommended -- at least 1000 IU Vitamin D and 1200 mg Calcium in an easily absorbed form.
I recommend the liquid Calcium/Magnesium combination to my patients. Along with weight-bearing exercise and a multi-vitamin that includes Vitamin D, minerals and herbs. There are several Chinese Medicine formulas to strengthen bones and prevent premature aging. These are primarily herbs that support the Kidneys and hormone system. Drynaria and Epimedium are two of the most important herbs for this problem.