Healthy Vitamin Choice logo and Home link

Home / Minerals And Deficiencies / Calcium


Calcium is an essential bulk mineral. It makes up bones and teeth and is essential for the transmission of information along the nerves and is used in the contraction of muscles. The importance of the right calcium balance for the maintenance of health can not be overestimated.

What are the functions of calcium?

Calcium is essential to:

Calcium also prevents muscle or leg cramps in some people.

What are the symptoms and signs of calcium deficiency?

Some of the indications of calcium deficiencies include skeletal abnormalities, such as osteopenia, osteomalacia, osteoporosis and rickets.

Osteomalacia is a failure to mineralize the bone matrix, resulting in a reduction of the mineral content of the bone. In children, osteomalacia is known as rickets. When children have rickets, their bones become soft and flexible, bending in ways normal bones would not. Features of rickets include bowed legs, beaded ribs, large foreheads, sunken chests (pectus excavatum), protruding chests (pectus carnitum) and hyperextendable joints.

Osteopenia is the presence of less than normal amount of bone. Osteopenia, if not treated, may result in osteoporosis.

Osteoporosis occurs when the composition of the bone is normal, but the mass is so reduced that the skeleton loses its strength and becomes unable to perform its supporting role in the body. In this case, fractures may occur due to minor falls and bumps, or bones may even break under their own weight. People with osteoporosis may have a hump in their backs, scoliosis (curvature of the spine), kyphosis (rounded shoulders) or lose height. These conditions may be caused by the buckling of their weakened spines, no longer being strong enough to hold the body upright.

The bones act as a reservoir for calcium. When the amount of calcium in the blood supply dips too low, calcium is borrowed from the bones. It is returned to the bones from calcium supplied through the diet. When diets are low in the mineral, there may not be sufficient amounts available to be returned to the bones. Over time, this net loss can lead to osteopenia or osteoporosis.

Other symptoms of calcium deficiency include:

Low calcium intakes have also been linked to premature births and some forms of cancer, including colon and breast cancer.

Calcium Absorption

Factors that facilitate the absorption of calcium include:

Vitamin D

Vitamin D is needed in order to adequately absorb calcium from the gastrointestinal tract. Vitamin D comes from two sources - diet and sunlight. Even with sufficient calcium, if vitamin D is not present, rickets and the adult version of rickets, osteomalacia, may result.

As people age they lose the ability to make vitamin D in their skin from sunlight. Because of this, getting enough vitamin D, for the elderly may be as important as getting enough calcium to prevent weak bones. One research study found that women who took a vitamin D supplement had higher bone density than women who did not take extra amounts of the vitamin.

Special note

There are a number of things which work against the absorption of calcium. These include:


Expert opinions are mixed on the role of alcohol in both calcium absorption and osteoporosis. While alcoholics tend to develop osteoporosis, a number of studies have linked moderate alcohol consumption to higher bone density than the bones of teetotalers. This increase in bone density for those who consume 3 - 4 drinks a week may be because alcohol increases estrogen levels, and estrogen increases the body's ability to utilize calcium and other minerals. A possible reason alcoholics tend to suffer from osteoporosis is that too much alcohol, in addition to its ability to raise estrogen levels, tends to replace more nutritious foods in the diet, including those with high amounts of calcium and other bone building nutrients.


Legumes and cereal grains such as whole wheat, oats, rye and barley contain phytates, which may interfere with calcium absorption. Phytates are reduced by baking, sprouting and fermentation.


Phosphorus is also an essential mineral, and sufficient quantities are needed for calcium to do its job in the body, but too much phosphorus can increase calcium requirements which, if not met, can leave a person calcium deficient. A junk-food diet which is rich in phosphorus can produce a relative calcium deficiency. Ideally the calcium : phosphorus ratio is 2 : 1.

Food sources

Some of the main sources of calcium in American diets are dairy products. It has been estimated that as much as 75% of the calcium consumed in the U.S. comes from these sources. However, many people in the world are unable to digest milk and other dairy products due to a condition called lactose intolerance. In lactose intolerant individuals, not enough of the enzyme lactase is produced, the enzyme needed to break down lactose. Lactose is the sugar found in milk. Most of the races in the world, especially those where dairy products have never been a part of the native diets for long periods, are lactose intolerant. Approximately 70 - 90 percent of adults of Asian, African, Native American and Mediterranean descent are lactose intolerant. People who are lactose intolerant, or who for other reasons do not consume dairy products, have a number of other options for getting calcium. These include:


Doses vary from person to person. It is recommended that calcium be taken in a good multimineral supplement, although extra doses may be taken up to 1,000 mg a day.


Do not take if you have:

Consult your doctor if you have:

Signs of calcium toxicity

As with many vitamins and minerals, too much as well as too little of calcium in the diet is not desirable. Excessively high intakes of calcium can interfere with the absorption of zinc, magnesium, iron, phosphorus and other nutrients. An increased intake of calcium in the diet increases requirements for magnesium, another mineral important for bone health.

It has been suggested that the recent trend towards fortifying foods with extra calcium, increasing calcium but not magnesium intakes, has caused a nationwide imbalance in optimal calcium to magnesium ratios. Research studies have shown that animals fed diets deficient in magnesium develop skeletal abnormalities, including osteoporosis.

When calcium in the body is too high compared to magnesium, excess calcium may be deposited in the soft tissues. This may result in calcium deposits in places such as the kidneys, the arteries and the heart.

While calcium is important for good health, including strong bones, it's important to keep in mind that it is not the only mineral involved in osteoporosis prevention. One major cause of osteoporosis is a calcium deficiency. It is not, however, the only cause, and not everyone who has osteoporosis is calcium deficient. Excessive amounts of calcium in relation to other minerals may do more harm than good.

Signs of toxicity can also include: confusion, slow or irregular heartbeat, bone or muscle pain, nausea and vomiting.

Back to Top


Bland, J. 1996, Contemporary Nutrition. J & B Associates.

Davies, S. and A. Stewart., 1997, Nutritional Medicine. Pan.

Holden, S., Hudson, K., Tilman, J. & D. Wolf, 2003, The Ultimate Guide to Health from Nature. Asrolog Publication.

Pressman, A. and S. Buff, 2000, The Complete Idiot's Guide to Vitamins and Minerals. (2nd Ed.) Alpha Books.

Soothill, R. 1996, The Choice Guide to Vitamins and Minerals. A Choice Book Publication.

Sullivan, K. 2002, Vitamins and Minerals: A Practical Approach to a Health Diet and Safe Supplementation. Harper Collins.

Back to Top

Newsletter Subscription
Has Closed

Manage Your Subscription

Personal details used only by us and not given to others for any reason.

Most Americans think they are getting enough calcium everyday, but, the fact is, they are not - they're calcium deficient.

Calcium deficiency is usually due to an inadequate intake of calcium. When blood calcium levels drop too low, the vital mineral is 'borrowed' from the bones.

It is returned to the bones from calcium supplied through the diet. The average person loses 400 to 500 mg of calcium per day.

If an individual's diet is low in calcium, there may not be sufficient amounts of calcium available in the blood to be returned to the bones to maintain strong bones and total body health.