CALCIUM:Is it Effective?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for CALCIUM are as follows:
Effective for…
Raising calcium levels in people who have low calcium.
Preventing low calcium levels.
Reversing high potassium levels, when given intravenously (by IV).
Use as an antacid as calcium carbonate.
Reducing phosphate levels in people with kidney disease.
Likely Effective for…
Treating osteoporosis (weak bones). Taking calcium by mouth is effective for preventing and treating bone loss and osteoporosis. Most bone growth occurs in the teenage years, and then bone strength in women remains about the same until age 30-40. After age 40, bone loss typically occurs at rates of 0.5% to 1% per year. In men, this occurs several decades later. There is more bone loss if less than the recommended amount of calcium is obtained from the diet. This is very common among Americans. Bone loss in women over 40 can be reduced by taking calcium supplements. Some researchers estimate that taking calcium for 30 years after menopause might result in a 10% improvement in bone strength, and a 50% overall reduction in bone break rates.
Preventing bone loss caused by insufficient calcium in the diet. This can reduce the risk of breaking bones.
Reducing symptoms of premenstrual syndrome (PMS). There seems to be a link between low dietary calcium intake and symptoms of PMS. Consuming calcium daily seems to significantly reduce mood swings, bloating, food cravings, and pain. Also, increasing calcium intake from food seems to prevent PMS. Women consuming an average of 1283 mg/day of calcium from foods seem to have about a 30% lower risk of developing PMS than women who consume an average of 529 mg/day of calcium. Taking calcium supplements, however, doesn’t seem to prevent PMS.
Increasing fetal bone density in pregnant women with low calcium intake.
Reducing bone loss in people taking drugs called corticosteroids, when used in combination with vitamin D.
Reducing thyroid hormone levels in people with kidney failure.
Possibly Effective for…
Reducing the risk of colorectal cancer. Research suggests that high intake of dietary or supplemental calcium seems to reduce the risk of colorectal cancer. Research also shows that taking calcium supplements might help to keep colorectal cancer from returning.
High blood pressure. Taking calcium supplements seems to reduce blood pressure slightly (usually around 1-2 mmHg) in people with or without high blood pressure. Calcium seems to be more effective in salt-sensitive people and people who normally get very little calcium. Taking calcium by mouth also seems to be helpful for reducing blood pressure in people with serious kidney disease.
High blood pressure in pregnancy (pre-eclampsia). Taking 1-2 grams of calcium by mouth each day seems to reduce pregnancy-related high blood pressure. Calcium appears to reduce the risk of high blood pressure in pregnancy by about 50%. Calcium appears to have the greatest effect in high-risk women and women with low calcium levels.
High cholesterol. Taking calcium supplements along with a low-fat or low-calorie diet might modestly reduce cholesterol. Taking calcium alone, without the restricted diet, doesn’t seem to lower cholesterol.
Reducing weight and body fat while dieting. Adults and children with low calcium intake are more likely to gain weight, have a higher body mass index (BMI), and be overweight or obese compared to people with high calcium intake. So researchers have studied whether increasing calcium intake might help with weight loss. Some clinical research shows that increasing calcium consumption from dairy products such as yogurt seems to increase weight loss, lean body mass, and body fat loss in people on a low-calorie diet as well as people on a regular unrestricted-calorie diet.
Preventing stroke in women.
Preventing fluoride poisoning in children when taken with vitamins C and D.
Reducing tooth loss in elderly people.
Possibly Ineffective for…
Preventing breast cancer in older (postmenopausal) women.
Reducing lead levels in breast-feeding women.
Insufficient Evidence to Rate Effectiveness for…
Preventing falls. Evidence suggests that calcium plus vitamin D might help prevent falls by decreasing body sway and helping to keep blood pressure normal. Calcium alone doesn’t seem to have the same benefit. Interestingly, calcium plus vitamin D seems to prevent falls in women, but not in men.
Metabolic syndrome. Some evidence suggests that getting more calcium from diet and supplements, either alone or in combination with vitamin D, might lower the risk of developing metabolic syndrome.
Cancer. Research shows that healthy older women who take 1400-1500 mg/day of calcium plus 1100 IU/day of vitamin D3 (cholecalciferol) have a 60% lower risk for developing cancer of any type.
Pregnancy-related leg cramps. Limited evidence shows that calcium can help prevent leg cramps in the second half of pregnancy.
Diabetes. Some evidence suggests that getting more calcium from diet and supplements, either alone or in combination with vitamin D, might lower the risk of developing type 2 diabetes.
Lyme disease.
Seizures.
Other conditions.
More evidence is needed to rate the effectiveness of calcium for these uses.