Calcium is the most abundant mineral in the human body. While celebrated for its role in the development and maintenance of strong, healthy bones and the fight against osteoporosis, it also supports other vital functions, including proper muscle contractions, a healthy heartbeat, and good cholesterol levels.
Where to find Calcium
Dairy products, as well as soy, nuts, beans, kale, turnip greens, collard, and most green leafy vegetables.
Note Calcium is easier to absorb in the gut from cooked foods, rather than raw.
Popup: Foods highest in Calcium
The Daily Value for Calcium is 1000 mg.
More about Calcium
Calcium is the most abundant mineral in the body, providing the structural matrix necessary for strong bones, teeth, and fingernails. Ninety-nine percent of our body's calcium is found in our bones and teeth. Sadly, most experts agree that over 30% of the population doesn't consume enough calcium even though most claim to drink "plenty of milk." The fact is, Americans consume, on average, about 800 mg of calcium per day — this is not a sufficient amount. Essential for a regular heartbeat, healthy cholesterol levels, nerve impulse conduction, and muscle contractions, this abundant mineral has many serious health benefits.
Long after we've stopped growing (well beyond our teenage growth spurts), our bones remain dynamic living tissue, literally being broken down and rebuilt every day. Osteoporosis — a serious condition characterized by weak, brittle bones — occurs when our bone loss outpaces bone regeneration. Literally translated into "porous bone," osteoporosis is responsible for at least 1.5 million bone fractures a year, with 4 times as many women suffering from it as men.
Calcium deficiencies leading to osteoporosis are most often found in postmenopausal women, although studies suggest female athletes may also be at increased risk, which may also lead to a higher risk for stress fractures. This is because female athletes have also been shown to consume less than the RDA for calcium, while in fact, their needs are greater than the RDA — typically, 1,200 to 1,500 mg per day.
Some other conditions that predispose women to osteoporosis are menopause, leanness (low bodyfat — below 15%), short stature, and small bones. Although experts don't fully understand the mechanisms and onset of osteoporosis, they have concluded that diets low in calcium, Vitamin D, and a lack of weight or resistance exercise are all significant contributing factors.
Science does provide hope though as numerous studies have confirmed that calcium supplementation can slow and even prevent the development of osteoporosis. Thus, calcium is one of the most prescribed minerals, especially for females.
In addition to its bone-building properties, calcium plays an essential role in muscular contraction. Athletes who eliminate calcium-rich products from their diets (and don't supplement) often suffer from muscle cramps. Reintroducing calcium back into their diets has been shown to significantly reduce that cramping. Researchers have also found that calcium supplementation in endurance athletes increases not only bone-mineral density but helps sustain their lean body mass as well.
More positively healthy news
Several studies have shown calcium supplementation may help reduce high blood pressure and that people with low calcium intakes tend to have higher blood pressure. This isn't a coincidence — it may be beneficial to supplement with calcium even if your blood pressure runs just a little high. Calcium has also been shown to help reduce congestive heart failure because it helps increase muscular contractions in the heart. And, calcium appears to "calm the nerves" by supporting the release of the neurotransmitters norepinephrine, serotonin, and choline acetylase — all of which are responsible for regulating nerve impulses.
More recently, research has revealed calcium's potential to reduce the symptoms of PMS (premenstrual syndrome) in women. One 1998 study published in the American Journal of Obstetrics and Gyneacology found that daily supplementation with calcium reduced aches and pains, food cravings, psychological symptoms, and water retention by up to 54%. It's been shown to help reduce the headaches, irritability, insomnia, and depression linked with menopause as well.
Beware the hype: coral calcium
You may think that with so many positive benefits, marketers wouldn't need to add anything new. Unfortunately, there are some less-ethical promoters who feel they have to pad calcium's many benefits with a few that don't stand up to science.
One unscrupulous promoter touts the benefits of coral calcium, saying it even cures cancer and other serious diseases. In fact, coral calcium isn't any different than other forms of calcium, which are available at a much more reasonable price. Plus, coral calcium may contain levels of lead that are above those allowed in California (though it's probably not high enough to be a health concern). The take away? Stick with the less expensive, less hyped calcium supplements.
While people who consume a lot of dairy products — over three glasses of milk or the equivalent a day — likely get plenty of calcium, some people do have greater needs for this vital nutrient. Especially female athletes, those who avoid dairy products, or individuals with high blood pressure. Fortunately, appropriate levels of calcium can be found in most high-potency multivitamin/mineral formulas.
Between 500 and 1,500 mg per day is best for increased bone-mineral density.
Calcium citrate has been shown to be more readily absorbable than other forms of calcium, such as calcium carbonate, which is more commonly found in vitamin/mineral formulas.
For best absorption, calcium should be taken three times a day with meals, trying to ensure one dose is taken last thing before going to bed.
Word to the wise
Proper calcium-to-magnesium ratio is important to our body's mineral balance and to prevent over-calcification. So when supplementing with calcium, magnesium should be added in a ratio of 1:2. For example, if supplementing with 1,000 mg of calcium, you should also take 500 mg of magnesium for proper mineral balance.
Synergists of Calcium
Recent research has demonstrated that taking Vitamin D with calcium can increase calcium absorption by up to 65%, even if you already have normal levels of Vitamin D.
Magnesium (1:2 ratio) can be used to help "shuttle" calcium into our bones as well as prevent over-calcification.
Lysine (500 to 1,000 mg per day) reportedly helps increase the absorption and conservation of calcium as well.
Recent research has demonstrated that calcium and phosphorus are co-dependant for bone growth and development.
Safety of Calcium
Individuals with kidney stones or a past history of them should consult their physicians before supplementing with calcium.
People with hyperparathyroidism or kidney disease should consult a health-care professional before supplementing with calcium.
Drugs that interact with Calcium
Calcium may lower the effectiveness of some antibiotics because they compete for absorption.
Toxicity of Calcium
High amounts (over 2,500 mg per day) may lead to constipation, bloating, or very mild gas.
Bans and restrictions