Calcium Usage

Calcium plays a number of roles in the body. For instance, calcium is involved in the contraction and dilation of blood vessels,²⁸ both of which affect blood pressure.

Read more about Hypertension and Calcium.

It appears that calcium supplements help increase levels of "good" (HDL) cholesterol. This improves the ratio of HDL to LDL ("bad") cholesterol, which is beneficial.

Read more about Lipid Disorders and Calcium.

According to most, though not all studies, use of calcium (especially in the form of calcium citrate) combined with vitamin D may modestly slow the bone loss that leads to osteoporosis . ¹ A rather surprising potential use of calcium came to light when a large, well-designed study found that calcium is an effective treatment for premenstrual syndrome (PMS). ² Calcium supplementation reduced all major symptoms, including headache, food cravings, moodiness, and fluid retention. It is at least remotely possible that there may be a connection between these two uses of calcium: weak evidence hints that PMS might be an early sign of future osteoporosis. ³ One small but carefully conducted study suggests that getting enough calcium may help control symptoms of menstrual pain . ⁴ Some, but not all, observational and intervention studies have found evidence that calcium supplementation may reduce the risk of colon cancer . ⁵ Risk reduction might continue for years after calcium supplements are stopped. ⁶ However, calcium supplements might increase risk of prostate cancer in men, as discussed in the Safety Issues section. For menopausal women, calcium supplementation, especially with vitamin D added, may reduce cancer risk in general. ⁷ Individuals who are deficient in calcium may be at greater risk of developing high blood pressure . ⁸ Among individuals who already have hypertension, increased intake of calcium might slightly decrease blood pressure, according to some, but not all, studies. ⁹ Weak evidence hints that use of calcium by pregnant mothers might reduce risk of hypertension in their children. ¹⁰ Calcium supplements might slightly improve the cholesterol profile. ¹¹ Calcium supplementation has also been tried as a treatment to prevent preeclampsia in pregnant women. While the evidence from studies is conflicting, ¹² calcium supplementation might offer at least a minimal benefit.

The drug metformin , used for diabetes, interferes with the absorption of vitamin B 12 . Interestingly, calcium supplements may reverse this, allowing the B 12 to be absorbed normally. ¹³ Rapid weight loss in overweight postmenopausal women appears to slightly accelerate bone loss. ¹⁴ For this reason, it may make sense to take calcium and vitamin D supplements when deliberately losing weight. It has been additionally suggested that calcium supplements, or high-calcium diets, may directly enhance weight loss, but current evidence is more negative than positive. ¹⁵ Finally, calcium is also sometimes recommended for attention deficit disorder , migraine headaches , and periodontal disease , but there is as yet no meaningful evidence that it is effective for these conditions.

It is important to note that despite the benefits of calcium supplementation for certain conditions, a large, placebo-controlled trial involving over 36,000 post-menopausal women found that daily supplements of 1,000 mg of calcium carbonate combined with 400 IU of vitamin D(3) for an average of seven years did not significantly reduce death rates from all causes.196