We need calcium for the development and maintenance of strong bones and teeth, and that’s where about 99% of the body's calcium is found. Calcium also helps the heart, nerves, muscles, and other body systems work properly. It is probably best known for helping prevent osteoporosis. Our body needs several other nutrients in order for calcium to be absorbed and used properly, including magnesium, phosphorous, and especially vitamins D and K.
Calcium is important for overall health. Almost every cell in our body uses calcium in some way. Some areas where our bodies use calcium are in our nervous system, muscles, heart and bone. Our bones store calcium in addition to providing support for our bodies. As we age, we absorb less and less calcium from our diet, causing our bodies to take more and more calcium from our bones. Over time this aging process can cause or contribute to osteopenia or osteoporosis.
Our bodies like to keep the amount of calcium in our blood within a certain narrow range. This range allows the cells in our body to stay healthy and perform jobs necessary for life. When blood calcium levels are low the amount of calcium in our blood goes below normal, our parathyroid glands release a hormone called parathyroid hormone (PTH). Although this sounds similar to thyroid hormone, PTH is different. PTH tells our bones to release more calcium into the blood stream. PTH also helps activate vitamin D which in turn increases intestinal calcium absorbtion.
The best way to get calcium is through food. Many foods are fortified with calcium, but some people may still need to take calcium supplements to get enough. It is especially important for children to get enough calcium in their diet as they are growing and forming bone, and for older people as they start to lose bone.We obtain vitamin D from the foods we eat and from our skin in response to sunlight. Because vitamin D promotes absorption of calcium from the intestine, vitamin D helps to build and maintain strong bones. When we have very low vitamin D levels, we can develop an adult form of rickets, called osteomalacia.
Postmenopausal women, people who consume large amounts of caffeine, alcohol, or soda, and those who take corticosteroid medications may need calcium supplements. Calcium deficiency can be found in people who don’t absorb enough calcium, as can happen with Crohn's disease, celiac disease, and some intestinal surgeries.
We need calcium to prevent the following conditions:
We need calcium to help build and maintain healthy bones and strong teeth. People start to lose more bone than their bodies make in their 30s, and the process speeds up as they get older. Studies have shown that calcium, particularly in combination with vitamin D, may help prevent bone loss associated with menopause. It may also help prevent bone loss in older men.
People with this condition have underactive parathyroid glands. These four small glands sit on the four corners of the thyroid in the neck and produce a hormone that regulates calcium, phosphorous, and vitamin D levels in the body. People with this condition should follow a high-calcium, low-phosphorous diet as prescribed by their doctor. Often, they will also need to take calcium supplements.
Premenstrual Syndrome (PMS)
One large, well-designed study showed that women who took 1,200 mg of calcium per day reduced their symptoms of PMS by 50%, including headache, moodiness, food cravings, and bloating. A smaller study suggested that calcium may help reduce menstrual pain.
High Blood Pressure
Some studies suggest that calcium supplements may play a role in the prevention of high blood pressure during pregnancy and preeclampsia, a combination of high blood pressure, fluid retention, and high levels of protein in the urine that some women develop during the last trimester of pregnancy. However, not all studies show the same benefit. Taking a prenatal vitamin, with magnesium, folic acid, and many other nutrients, and getting enough calcium in food, may lower the risk of developing high blood pressure during pregnancy.
Obesity and Weight Loss
Some animal and human studies have found that eating low-fat dairy products may help you lose weight or stay at a healthy weight.
Preliminary studies in animals and people suggest that calcium supplements, in the range of 1,500 - 2,000 mg per day, may help to lower cholesterol slightly. From these studies, it seems that calcium supplements, along with exercise and a healthy diet, may be better at keeping cholesterol at normal levels than at lowering already high cholesterol.
Rickets causes softening and weakening of the bone in children. Although very rare in North America and Western Europe, where children drink a lot of milk, it still happens in many parts of the world. Researchers thought rickets was caused by a vitamin D deficiency. But a study in 2000 showed that taking calcium supplements is an effective treatment.
Although not all studies agree, some show that people who have higher amounts of calcium, vitamin D, and milk in their diets are less likely to develop colorectal cancer than those who have low amounts.
Food sources of calcium
The richest food sources of calcium include cheeses, such as parmesan, Romano, gruyere, cheddar, American, mozzarella, and feta; low-fat dairy products, such as milk and yogurt; tofu; and blackstrap molasses. Some other good sources of calcium include almonds, brewer's yeast, bok choy, Brazil nuts, broccoli, cabbage, dried figs, kelp, dark leafy greens (such as dandelion, turnip, collard, mustard, kale, and Swiss chard), hazelnuts, oysters, sardines, and canned salmon. Foods that are fortified with calcium, such as juices, soy milk, rice milk, tofu and cereals, are also good sources of this mineral.
There are many forms of calcium available as dietary supplements. They differ in the amount of calcium they have, how well the body absorbs them, and how much they cost. The two most popular forms are calcium citrate and calcium carbonate.
Calcium citrate: Easily absorbed and digested by the body. It does not contain as much elemental calcium -- the amount your body actually absorbs -- as calcium carbonate. It is more expensive than calcium carbonate. Also, calcium citrate should not be used with aluminum-containing antacids
Calcium carbonate: Less expensive than calcium citrate and contains more elemental calcium. Requires a certain amount of stomach acid to be absorbed, so it is usually taken with a glass of orange juice. Many antacids contain calcium carbonate.
Calcium supplements that are derived from oyster shells, dolomite, and bone meal are best avoided as they may contain lead, a toxic metal that can harm the brain and kidneys, cause anemia, and raise blood pressure.
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