Calcium is a vital mineral in the human body, critical for bone structure, cellular processes, and a range of physiological functions.
However, recent evidence suggests that calcium supplements can pose cardiovascular risks. The disparity lies between dietary calcium and calcium supplementation.
Calcium and Its Importance: Around 99% of calcium in the human body contributes to the structure of bones and teeth. The remaining 1% participates in vital functions like vascular tone, muscle contraction, nerve impulse transmission, and hormonal secretion. The recommended daily intake is 1000 mg for men aged 19-70 and women aged 19-50, and 1200 mg for men over 71 and women over 51.
Role of Vitamin D: Vitamin D plays a significant role in calcium homeostasis, enabling the absorption of calcium from the intestine and promoting its storage in the bones. Normal bone mineral density (BMD) signifies the proper functioning of this mechanism.
Calcium Supplementation: Calcium supplementation has been widely adopted, particularly among the elderly, to maintain or improve BMD. Some studies show positive effects of supplementation on BMD, particularly in children and adolescents, but its impact on mature skeletons is unclear.
Issues with Supplementation: Despite the benefits to bone health, calcium supplementation has been associated with cardiovascular risks. Calcium supplements rapidly increase circulating calcium, which can lead to the progressive calcification of arteries, increasing cardiovascular risk. Dietary calcium, however, doesn't seem to pose this risk as it is assimilated more slowly.
Combining Calcium and Vitamin D: The impact of calcium supplementation on fracture risk appears to be enhanced when vitamin D is also administered. Despite this, a recent study found that high-dose vitamin D supplementation doesn't result in lower cardiovascular events or cancer incidence.
Concerns with High Calcium Intake: High calcium intake, particularly from supplements, could potentially increase the risk of myocardial infarction (MI) due to a sharp increase in serum calcium levels and subsequent calcification. However, the optimal dosage and regimen for supplementation remain uncertain.
Morelli, Marco B et al. “Calcium supplements: Good for the bone, bad for the heart? A systematic updated appraisal.” Atherosclerosis vol. 296 (2020): 68-73. doi:10.1016/j.atherosclerosis.2020.01.008
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