Calcium supplementation
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Calcium Supplementation and Body Weight
Research shows that calcium supplementation generally has little to no effect on body weight in adults, including those who are overweight or obese. Large meta-analyses and systematic reviews found that calcium supplements may result in a very small reduction in body mass index (BMI), waist circumference, and fat mass, but these changes are minimal and the evidence is of low to moderate certainty Li2016Cormick2024. However, some studies suggest that calcium supplementation can reduce body weight in children, adolescents, adult men, and premenopausal women, especially those with a normal BMI, but not in postmenopausal women or those who are overweight or obese .
Calcium Supplementation and Bone Health
Effects in Young People
Calcium supplementation in people under 35 years old is associated with increased bone mineral density (BMD) and bone mineral content (BMC), particularly at the femoral neck and total body. The effect is more pronounced in individuals aged 20–35 years compared to those under 20, suggesting that preventive supplementation before or around the time of achieving peak bone mass may be beneficial for long-term bone health .
Effects in Postmenopausal Women and Older Adults
For postmenopausal women, combined calcium and vitamin D supplementation can modestly increase BMD and reduce the risk of hip fractures, but the benefit is small Harvey2017Liu2020. Supplementation with calcium alone is not strongly supported for fracture reduction, and the most significant benefits are seen when calcium is combined with vitamin D, particularly in those at high risk of deficiency or those receiving osteoporosis treatment Harvey2017Chiodini2018Liu2020. Dairy products fortified with calcium and vitamin D may have a more favorable effect on bone health than supplements alone .
Risks and Side Effects of Calcium Supplementation
Calcium supplementation is associated with several potential side effects. Common adverse effects include gastrointestinal symptoms and an increased risk of kidney stones Harvey2017Chiodini2018Reid2015. Some studies have raised concerns about a possible increased risk of cardiovascular disease (CVD), particularly in healthy postmenopausal women, with a reported 15% higher risk of CVD and a 16% higher risk of coronary heart disease (CHD) in those taking calcium supplements Myung2021Kong2024Reid2015. However, the evidence for increased cardiovascular risk is mixed, and some reviews do not find convincing support for this association Harvey2017Chiodini2018Kong2024.
Recommendations for Calcium Supplementation
Current evidence suggests that routine calcium supplementation is not necessary for the general population, especially for those with adequate dietary intake. Supplementation may be considered for individuals at high risk of calcium and vitamin D insufficiency, such as older adults, postmenopausal women, or those with osteoporosis, and should ideally be combined with vitamin D Harvey2017Chiodini2018Liu2020. For most people, obtaining calcium from dietary sources is preferable, and supplementation should be tailored to individual risk factors and needs Harvey2017Chiodini2018Reid2015.
Conclusion
Calcium supplementation offers modest benefits for bone health, particularly when combined with vitamin D in high-risk groups, but has little effect on body weight for most adults. The potential risks, including gastrointestinal issues, kidney stones, and possibly increased cardiovascular risk, should be weighed against the benefits. For most people, a balanced diet with adequate calcium is sufficient, and supplementation should be reserved for those with specific needs or deficiencies.
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