According to meta-analyses of randomized controlled trials, supplementing with calcium (500 to 1,200 mg per day) and vitamin D (400 to 800 IU per day) can reduce the risk of fractures, especially hip fractures, in adults who are at least 50 years old.[1][2][3] Additionally, the magnitude of benefit is greater in older (age ≥80) than younger (age <80) adults and among adults living in long-term care facilities than adults who live in the community.[3]
In people under the age of 35, calcium supplementation (200 to 2,000 mg per day) can improve total body bone mineral density (BMD), and it seems to be particularly effective in increasing the BMD of the femoral neck relative to other sites.[4] Additionally, the magnitude of benefit is greater in people with inadequate calcium intake at baseline. Adequate calcium intake is fundamental to promoting and maintaining bone health, but like other nutrients, supplemental calcium will improve bone health only if dietary calcium intake is inadequate.[5]
There has been some concern of risk of cardiovascular disease when supplementing with calcium. However, in meta-analyses of adults at a higher risk of conditions related to calcium insufficiency (e.g., postmenopausal women, those with low-trauma fractures, mobile elderly), calcium supplementation (500 to 2,000 mg per day, over durations of 1.5 to 11.9 years) was not found to be associated with an increased risk of cardiovascular events or death.[6]