The conventional wisdom is that adequate calcium and vitamin D supplementation is a cost-effective way to combat age-related bone loss and osteoporotic fractures. As a result, the National Institutes of Health recommends a calcium intake of 1,500 mg/d for postmenopausal women and 1,000 mg/d for people younger than 65 years of age on hormone replacement therapy, while the American Osteoporosis Society recommends a calcium intake of 1,200 mg/d for women older than 50 years of age. Glucocorticoid users. In recent years, several studies have suggested that calcium and vitamin D supplementation may have potential negative effects, such as increased risk of cardiovascular events and all-cause mortality, and there is much debate as to whether the benefits to the skeletal system outweigh the adverse effects, so calcium and vitamin D supplementation should be used with caution. Do calcium supplements increase the risk of cardiovascular disease? Excessive calcium supplementation is not recommended for women. Recent evidence from Sweden suggests that calcium supplementation above 1400mg/d is associated with harm and increased cardiovascular events and mortality. The role of calcium in the cardiovascular system has been explored since the 1960s. Researchers found that calcium binds to fatty acids and bile acids in the intestines, reducing fat absorption and thus lowering blood cholesterol levels. Later studies also found that calcium supplementation lowered blood pressure and reduced body weight. This series of studies led clinicians to believe that calcium supplements may benefit the cardiovascular system. However, in recent years, three large randomized trials (RECORD, Akron, and Heidelberg studies) have found that calcium supplementation may increase the risk of ischemic heart disease and stroke in women. The mechanism by which calcium intake increases the incidence of cardiovascular events is not yet clear. Calcium-rich diets have been shown to decrease levels of osteotriol and increase levels of fibroblast growth factor 23 (FGF23), which is thought to be strongly associated with increased risk of cardiovascular events and all-cause mortality. Elevated blood calcium levels may also induce hypercoagulability and increase arterial stiffness. It has also been suggested that calcium intake causes a rapid rise in blood calcium and increases the risk of vascular calcification. Studies have shown that in middle-aged and older women, the risk of calcification of the abdominal aorta increases by 23% for every 0.1 mmol/L increase in blood calcium levels. Vitamin D supplementation, helpful or harmful? High and low blood levels of 25-(OH)D may increase the risk of cardiovascular disease, malignancy, and death. Therefore, it is not recommended to over-supplement with vitamin D. Vitamin D regulates intestinal, bone, and renal calcium absorption, so adequate vitamin D is important for bone mineralization, regulation of parathyroid hormone secretion, and maintenance of normal blood calcium and phosphorus concentrations. In recent years, controversy has arisen regarding the safety of vitamin D use. On the one hand, some studies have found that vitamin D intake is effective in reducing fracture risk only if it is not less than 700 IU/d. Calcium and Vitamin D. Can they protect bones? For healthy postmenopausal women, vitamin D3 or calcium supplements are not recommended to prevent fractures. The combined use of calcium and vitamin D in postmenopausal women has long been thought to be effective in increasing bone mineral density and reducing fracture risk. Since 2004, however, five large-scale randomized controlled studies have found that calcium supplementation does not significantly reduce fracture risk. Instead, calcium use may cause gastrointestinal adverse effects. There were even isolated studies that found a mild increase in fracture incidence with calcium supplements. These studies question whether the protective effects of calcium supplements on bone can outweigh their possible adverse effects. Can the increased incidence of kidney stones be attributed to calcium supplements? The risk of kidney stones is small in people who supplement with vitamin D and calcium. Further studies are needed to verify the exact risk.