Updated: May 15, 2019
Calcium is a mineral that is necessary for all living organisms to build bones and keep them healthy. Calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99 percent of the calcium in our bodies is in our bones and teeth.
Calcium is crucial in growing new bone and maintaining bone strength. The concentration of calcium in the body tends to decline as we age through our skin, nails, hair, sweat, urine and feces everyday. In addition, as women age, absorption of calcium tends to decline due to reduced estrogen levels. Calcium absorption can vary depending on race, gender, and age.
As our body cannot produce its own calcium, it is important to get enough calcium from the food we eat. When we don't get the required amount of calcium for our body, it is taken from our bones. This can lead to weakening of bones which are prone to break.
Not getting enough amount of calcium every day can lead to bone loss, low bone density and even broken bones. Taking extra calcium helps the bones rebuild properly and stay strong.
Dietary calcium can be found in several different foods and drinks. We can obtain calcium from a variety of sources.
The following foods and drinks are rich sources of calcium:
Also, many drinks, including soy milk and a variety of fruit juices are fortified with calcium. If you drink soymilk or another liquid that is fortified with calcium, be sure to shake the container well as calcium can settle to the bottom. Crushed eggshells contain calcium and can be ground into a powder and added to food and drink.
A simple way to add calcium to many foods is to add a single tablespoon of nonfat powdered milk, which contains about 50 mg of calcium. It is easy to add a few tablespoons to almost any recipe.
Some dark green vegetables may contain high levels of oxalic acid which reduces the ability of our body to absorb calcium.
The people at highest risk of a calcium deficiency are postmenopausal women. Since dairy products are one of the most common sources of calcium, people who are lactose intolerant or vegan are also at increased risk of calcium deficiency.
Taking calcium carbonate by mouth as an antacid is effective for treating indigestion.
Taking calcium carbonate or calcium acetate by mouth is effective for controlling high phosphate levels in the blood in people with kidney failure. Calcium citrate is not effective for treating this condition.
Giving calcium gluconate intravenously (by IV) can reverse hyperkalemia, a condition in which there is too much potassium in the blood.
Taking calcium by mouth is effective for treating and preventing hypocalcemia, a condition in which there is low levels of calcium in the blood. Also, giving calcium intravenously (by IV) is effective for treating very low levels of calcium.
Taking calcium by mouth is effective for preventing bone loss and treating osteoporosis. Most bone growth occurs in the teenage years. Bone strength in women remains about the same until age 30 to 40. After age 40, bone loss typically occurs every year. However, in men, this bone loss occurs several decades later. Bone loss is greater in people getting less than the recommended amount of calcium from their diet. Bone loss in women over 40 can be reduced by taking calcium supplements. Taking calcium for 30 years after menopause might result in a 10 percent improvement in bone strength. Taking calcium alone or with vitamin D also helps prevent fractures in people with osteoporosis.
Taking calcium along with vitamin D seems to reduce the loss of bone mineral in people using corticosteroid drugs for long-term.
Taking calcium by mouth reduces parathyroid hormone levels in people with kidney failure and parathyroid hormone levels that are too high.
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 the amount of calcium in your diet might prevent PMS. Women consuming an average of 1283 mg/day of calcium from foods seem to have lower risk of PMS than women who consume an average of 529 mg/day of calcium.
High intake of dietary or supplemental calcium reduces the risk of colorectal cancer. However, some conflicting evidence exists. This may be due to differences in blood levels of vitamin D. People with low levels of vitamin D do not seem to benefit from calcium supplements.
Calcium supplementation increases the bone mineral density of the fetus in pregnant women who eat a low amount of calcium as part of their diet. However, this does not appear to be beneficial for women with normal calcium levels.
Taking calcium and vitamin D by mouth appears to help prevent tooth loss in older people.
Taking calcium by mouth, together with vitamin C and vitamin D supplements, seems to reduce fluoride levels in children and improve symptoms of fluoride poisoning.
Taking calcium supplements along with a low-fat or low-calorie diet seems to modestly reduce cholesterol. However, taking calcium alone, without the restricted diet, does not seem to lower cholesterol.
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 work best 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.
It is condition with high blood pressure during pregnancy. Taking 1-2 grams of calcium by mouth daily seems to reduce pregnancy-related high blood pressure. Calcium appears to have the greatest effect in high-risk women and women with low calcium levels.
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. Increasing calcium intake might help with weight loss. Results are mixed.
Increasing calcium consumption from dairy products, such as yogurt, increases 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. Also, taking calcium supplements along with vitamin D seems to increase weight loss in people who have inadequate intake of calcium. Calcium supplements don't seem to increase weight loss in people with adequate calcium intake. Also, calcium does not appear to increase weight loss in people who are not overweight.
Women who eat more calcium have a reduced risk for developing breast cancer. However, other research suggests that blood levels of calcium are not linked with breast cancer risk. Therefore, taking calcium does not reduce the risk for breast cancer.
There is no association between calcium supplementation and the risk of heart disease in healthy people.
People who consume more calcium in their diet have a lower risk of having a heart attack. However, the effects of calcium Supplements on heart attack risk are not clear. Some research suggests that calcium supplements increase heart attack risk. Other research shows there is no effect. Some people have an increased risk while others do not. For example, people who take calcium as a single supplement might have an increased risk. On the other hand, people who take calcium with vitamin D do not seem to have an increased risk. Also, people who take a calcium supplement and consume more than 805 mg/day of calcium as part of their diet might be at an increased risk, while people who take a supplement and consume less calcium in their diet might not.
Taking calcium alone or with vitamin D does not seem to prevent fractures in older people without osteoporosis.
Administering calcium during cardiac arrest does not increase survival and might actually worsen the chance for resuscitation.
Taking calcium alone does not reduce the risk of cancer. Taking calcium along with vitamin D might reduce the risk of cancer in some people, but results are conflicting. Some research shows that taking 1400-1500 mg of calcium daily plus 1100 IU of vitamin D3 (cholecalciferol) daily lowers the risk of developing cancer in healthy older women who have low blood levels of vitamin D before treatment.
But other research shows that taking 1500 mg of calcium daily plus 2000 IU of vitamin D3 (cholecalciferol) daily does not reduce the risk of developing cancer in healthy older women who have adequate levels of vitamin D before treatment.
Taking calcium supplements might reduce the risk of developing endometrial cancer. However, dietary calcium does not seem to have any benefit.
High blood levels of calcium are linked to a reduced risk of ovarian cancer. However, other early research suggests that dietary calcium intake is not linked with the risk of ovarian cancer.
The effect of calcium on the risk of prostate cancer is conflicting. Some research suggests that taking calcium supplements daily decreases the risk of prostate cancer. However, other research suggests that there is not a link between calcium intake and the risk for developing prostate cancer.
Consuming more calcium from the diet or from supplements, either alone or in combination with vitamin D, lowers the risk of developing type 2 diabetes.
Increasing calcium intake in the diet might decrease the risk of stroke. Other evidence suggests that increasing calcium intake does not reduce the risk of stroke.
Taking calcium with a high dose of vitamin D does not reduce pain during painful periods. However, taking calcium without vitamin D might be beneficial.
Taking calcium supplements does not lower the levels of lead in the blood. However, other research suggests that taking calcium reduces blood lead levels.
Calcium plus vitamin D might help prevent falls by decreasing body sway and helping to keep blood pressure normal. Calcium alone does not seem to have the effect. However, calcium plus vitamin D seems to prevent falls in women, but not in men.
Consuming more calcium from the diet and supplements, either alone or in combination with vitamin D, lowers the risk of developing metabolic syndrome.
Taking calcium supplements might reduce vitamin B12 deficiency caused by the diabetes drug metformin.
Using a mouth rinse containing calcium phosphate in combination with fluoride treatments reduces the duration of pain in people with mouth ulcers due to stem cell transplants.
The effects of calcium on nerve damage caused by oxaliplatin is mixed. Some research shows that giving a calcium and magnesium into the vein reduces nerve pain caused by this drug. But other research shows that it has no benefit.
Taking calcium daily, beginning 11 to 21 weeks into pregnancy, reduces depression at 12 weeks after delivery.
Calcium can help prevent leg cramps in the second half of pregnancy.
Calcium might help control seizures resulting from sudden drops in blood levels of calcium.
More evidence is needed to rate the effectiveness of calcium for Lyme disease and Other conditions.
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