Doctors and health advocates suggest that men and women need to take at least 1000-1200 mg/day of calcium to prevent bone fractures but most Americans only get 700-900 mg/day. As such, millions of people have turned to calcium rich or fortified foods or to supplements to increase their intake of calcium to meet these recommendations. However, in a new assessment of the available evidence, the evidence suggesting benefits from increasing calcium intake is very weak.
The investigators did a meta-analysis of all clinical trials assessing this issue so it is the most all-inclusive assessment on this topic to date. They found that the universal use of calcium supplements or approaches to enhance dietary calcium did reduce the incidence of any bone fractures by 11% which means that 77 people over 50 years of age would need to be treated for 5.5 years in order to prevent one fracture of any kind. However, when they looked carefully at the studies that made up the meta-analysis, they found that studies in people with severe blood calcium and vitamin D deficiencies had a lot of benefit from supplementing with calcium and vitamin D but the majority of people who just had lower intake of calcium with or without vitamin D did not have much benefit at all. So you can see why the past information that consumers heard were all over the place, one set of studies are in people with a lower than recommended intake while the other group had severe deficiencies at baseline.
People with real deficiencies in vitamins and minerals benefit from supplementing but trying to take high doses of vitamin E, vitamin C, or beta-carotine is not heart healthy. If you are dehydrated, you will benefit from drinking water but drinking lots of water is no better than drinking a normal amount. This data on calcium supplementation is consistent with that. The recommended daily allowances are not created based on solid evidence and sometimes they get it wrong. The body is good at holding onto what it needs as long as your diet is reasonable. So if your doctor tests your blood and you have lower than normal calcium concentrations or deficiencies in vitamin D, there is good evidence that if you supplement you will get health benefits. However, if you have a reasonable diet, there is little chance of benefit and you are wasting your time and your money by trying to increase calcium concentrations. Even more worrisome, people taking high doses of calcium are also increasing their chances for constipation or calcium kidney stones and are more likely to be hospitalized for these issues. There are many prescription options that have been proven to help strengthen your bones and prevent bone fracture that your doctor can discuss with you.
