Caution about Calcium Supplements

caution-efficacy-of-calcium-supplements-on-bone-mass-in-postmenopausal-womenAlongside vitamin C and other supplements that everyone seems to be taking nowadays, calcium is among the hottest sellers. To move calcium off the shelf often companies will make claims regarding their specific calcium blend trying to make it appear more effective than the competitors. Unfortunately, not everything these companies say is true, and the uneducated consumers are the ones who end up paying the consequences in the long run with their health. This article deals with some of the issues around calcium supplements and how not to be fooled into buying the wrong one.

Calcium and Health

Calcium is all over the place in the body. Ninety-nine percent of it is found in the bones and teeth, most of the rest is in the blood. The reason that is important to know is because if calcium levels in the blood drop below normal, calcium gets leached out from the bones. Therefore, it is important to eat enough calcium so adequate blood calcium levels can be maintained.

Calcium and Disease Prevention

Osteoporosis – Osteoporosis is a very real health concern for all older women. Although there are many ways of preventing osteoporosis before it becomes very serious, it unfortunately strikes many women as they age decreasing their quality of life in various ways.  Literally, osteoporosis means “porous bone,” and is characterized by a decrease in bone mineral density, bone calcium content, and an increased risk of fractures. Hospitals commonly have to deal with older women with broken bones that are sometimes even life-threatening. These women’s bones become weakened to the point that they must be very careful in their movements so not to fall or hurt themselves. Even a minor fall on the wrong part, such as the hip or a major bone in the body, could lead to a fracture impossible in younger people.

Osteoporosis risk factors that cannot be changed are:

  • Being female
  • Postmenopasual
  • Having a small skeleton
  • Being Caucasian / Asian
  • Family history of osteoporosis and fractures
  • Advanced age

Osteoporosis risk factors that can be changed are:

  • Medications with negative affects on bone
  • Inadequate or excessive intake of certain nutrients
  • Sedentary lifestyle – no weight bearing activity
  • Too much exercise
  • Low body weight
  • Cigarette smoking
  • High alcohol consumption

How should I get my calcium?

There is no replacement to healthy eating. Food is the best source for calcium. Meals provide many other nutrients that are also needed for bones and the body.  Nevertheless, supplements can also help when someone is not getting the calcium they need because having proper calcium is absolutely necessary. As such, choosing the right supplement becomes just that much more important, especially since there are so many supplements out there advocating their product.

Factors that increase calcium absorption

Any calcium that one ingests, whether from food or from supplementation, is absorbed in a specific place in the intestines called the small intestine. It’s not all absorbed, however, because there are many factors that can block calcium from entering the body often causing it to pass right through the system. Depending on the form of calcium taken, how much was taken, and how it dissolved in the intestines, all predict the amount that will be absorbed.

Stomach Acid – Calcium absorption requires an acidic environment. That being the case, antacids, such as calcium carbonate, which are often touted as ideal calcium supplements, actually inhibit calcium absorption into the body. If this form of calcium is taken during a meal, when stomach acid is normally increased, then absorption can take place. Nonetheless, peoples’ level of acid production is an additional barrier for absorption. Unfortunately, due mainly to misleading advertisement by these companies, many people have been popping antacids away from food for years, hoping they may be warding off diseases such as osteoporosis. The other disadvantages also to using antacids, or any drugs on a regular basis, are the side effects they may cause in the long run. The healthy body innately tries to reach balance and by neutralizing an environment that is supposed to be at a specific acidic pH is asking for the body to react with more acid than it accustomed, potentially complicating a person’s digestive issues.

Vitamin D – For calcium to be absorbed, vitamin D has to be active in the body. Many supplements now have vitamin D as well with the calcium. In many places in the world vitamin D supplements are usually not necessary because vitamin D is available from vitamin D fortified milk, foods such as fish and egg yolks, and mild exposure to sunlight by the skin. But many people, especially women in the Muslim world who cover much of their body, sometimes don’t even get that. In general, most peoples’ vitamin D requirements can easily be met by exposing their hands, feet, and face for 30 minutes to sunlight from their courtyards or from well sun lit areas within their home.

Low calcium intakes – The more calcium you eat the less your body absorbs. The best way to take calcium is in smaller doses throughout the day. You should not take more than 500 milligrams of calcium at one time and allow 4 to 6 hours between doses. As such, the once-a-day large tablets may not be providing enough calcium for your bodies requirements.

Calcium supplements


How well calcium supplements dissolve in the intestines is a factor that affects their absorption. To make sure your supplement dissolves properly check to see if it meets U.S. Pharmacopeia’s (USP) standards for dissolution. This indicates that the supplement meets the U.S. Pharmacopeia’s standards for the amount of elemental calcium in a tablet and how well the tablet dissolves.

Types of calcium

When you buy a calcium supplement you will see that it is combined with another substance. The most popular substances that calcium is compound with are carbonate and citrate. The amount of calcium in a compound is called elemental calcium. During digestion, the calcium compound dissolves and the elemental calcium becomes available for absorption. For example, if a tablet says that it has 500 milligrams of calcium carbonate, what that actually means is that there is only 200 milligrams of elemental calcium available. This is because only 40% of a calcium carbonate compound is elemental calcium. The other 60%, or 300 milligrams, is from the carbonate ingredient. Nowadays there are many calcium citrate and calcium carbonate on the market. Citracal® and Solgar® are brand name calcium citrate products. Tums® and Caltrate® are brand name calcium carbonate products.

Some other less popular forms of calcium supplements also exist, such as calcium ascorbate (calcium and vitamin C), but the molecules they are bound to sometimes are larger than the calcium. As such, a calcium ascorbate tablet often has much less calcium than vitamin C. This may be sufficient if one only wants to add a little calcium to the diet and is also looking for Vitamin C, but for those who need more calcium, calcium ascorbate is likely not the right choice. Just trying to reach the adequate dose of calcium from calcium ascorbate tablets would produce diarrhea, a side effect of excess vitamin C.

Dangerous compounds in calcium supplements

There are some naturally occurring calcium supplements that are from sources which are found to have a heavy metal content. Lead, for example is found in Dolomite, Oyster shell, and Bone Meal. Lead is a dangerous metal to have in the body, especially for pregnant and nursing women, as well as children. Currently, calcium supplements are not tested by a regulatory agency for lead content.

Another ingredient to watch out for is aluminum, mainly found in antacids that are also being sold as calcium supplements. Aluminum, compound with hydroxide and used to increase the antacid effect of the medicine, can be absorbed. Over-the-counter antacids are actually the main source for human aluminium exposure. Aluminum is toxic to the nerves and can cause various toxic effects for developing child in the womb. Despite this, patient information leaflets on aluminum containing antacids show substantial differences regarding warnings from aluminium toxicity. Instead, many companies downplay the importance of the aluminum in their calcium product by explaining that the aluminum is minimally absorbed because the calcium takes its spot for absorption into the body. What they don’t tell you is that the opposite is also just as true; the aluminum in these supplements equally blocks calcium for absorption!

The Crux 

  • Consume enough calcium daily to stay healthy and reduce your risk for developing osteoporosis.
  • Avoid taking more than 500 milligrams of elemental calcium at one time to increase absorption.
  • Adequate vitamin D in the body is important for calcium absorption
  • Try to consume calcium from foods or beverages. If you take calcium supplements, calcium citrate is the best absorbed because it does not require any additional stomach acid. It is also not the form found in antacids.