Calcium is important for contraction of muscles (including our heart, a muscular organ), transmission of nerve impulses, secretion of hormones and enzymes, and mineralization of bones for body structure and support. It is the most abundant mineral in our body. Most of the calcium in our body is found in our bones and teeth while a very small concentration is found in body fluids, including our blood and the fluid in between cells. The calcium stored in our bones is given up to the bloodstream in order for our body to carry out vital processes. Calcium from food sources is utilized to replace used calcium to maintain the balance of calcium levels in the blood and bones.

The challenge is that most of us do not get the right amount of calcium from our diet. The situation is further complicated by the fact that absorption of calcium decreases as we age. Likewise, our senior loved ones undergo bone breakdown faster than bone formation. Thus, inadequate calcium intake, reduced calcium absorption and increased bone loss all contribute to the risk of osteoporosis for our loved ones aged 50 and above.

In 2002, calcium supplements were the leading mineral supplement sold in the United States, with sales amounting to $877 million. Choosing from a wide array of calcium supplements displayed in pharmacy shelves can be very difficult and confusing. Here are a few tips to guide you in selecting the right supplement for your loved ones, and for yourself as well.

There are two main forms of calcium contained in supplements, namely citrate and carbonate. These are also referred to as calcium salts. Other calcium salts include lactate, phosphate and gluconate. Calcium carbonate is the most common and the least expensive, making it the most popular commercial choice. Calcium carbonate also contains the highest amount of elemental calcium (40%) while calcium gluconate has the least (9%). Calcium phosphate has 38%, citrate contains 21% while lactate has 13%. The amount of elemental calcium refers to the actual amount of calcium contained in the supplement. It can be computed as follows: Calcium citrate 500mg x 21% = 105mg of elemental calcium. Therefore, when browsing through bottles, it is important to check the amount of elemental calcium, not just the dosage strength (i.e. 500mg of calcium lactate).

Some calcium supplements may contain lead. Therefore, the public is advised not to use bone meal or dolomite as calcium source. These products are suspected to contain lead, a substance that damages the brain and kidneys in toxic amounts. Bone meal is made from crushed bones and was formerly used as source of human dietary calcium. Dolomite, on the other hand, is a rock made up of calcium-magnesium-carbonate complex.

When your loved ones are taking calcium tablets, it is recommended that these supplements be taken with meals for better absorption. Patients who are also taking biphosphonates (medication for osteoporosis) should also wait at least 30minutes (one hour for ibandronate) before taking their calcium supplements since calcium interferes with the absorption of these drugs. Calcium citrate does not require stomach acids for absorption. Thus, this salt form may be recommended to patients who have low gastric acid levels. If your loved ones experience side effects of calcium (especially in doses greater than 500mg) such as bloating (stomach gas) and constipation, administer the calcium supplement in divided doses within the day. Also, increase dietary fiber and fluid intake to remedy constipation. However, if the adverse effects continue or worsen, consult your physician before stopping or changing medications.

Although calcium is very important, taking it in large doses is also dangerous. Harmful effects include hypercalcemia, a condition of excessive calcium levels in the blood. However, diet and supplements rarely result to this condition. Calcium also has the potential to interfere with absorption of other minerals which include magnesium, phosphorus, iron and zinc. High amounts of calcium can also affect normal functioning of our kidneys. The maximum amount of daily calcium intake for children and adults is 2500mg/kg.

Vitamin D, in large amounts, may also have adverse effects. Vitamin D is needed for calcium absorption but is toxic to body cells at doses greater than 800IU per day. Thus, before giving your senior loved ones calcium and other supplements, check with your physician who will determine the need for calcium intake. You may also consult a pharmacist and/or registered dietician regarding the calcium needs of your loved ones.

Below is a list of some calcium supplements in the United States:

Calcium carbonate:

Calcium carbonate (generic)

Calcium carbonate + vitamin D (generic)

Caltrate + vitamin D

Os-Cal + Vitamin D

Tums Ultra

Viactiv

Calcium citrate:

Calcium citrate (generic)

Citracal + Vitamin D

Calcium phosphate:

Posture-D

Calcium complex (carbonate+lactate+gluconate):

Calcet