The Myth of Calcium Supplements: Which One Is The Best?

Written By: Gloria Tsang, RD

Title: Founding Registered Dietitian

Alumni: University of British Columbia

Last Updated on:

The role of calcium in bone health is indisputable. We’ve previously talked about food sources of calcium, we will spend some time discussing the different forms of calcium supplements.

How Much Calcium?

The Dietary Reference Intake DRI for calcium for adults is 1000 mg – 1300 mg depending on age and gender. As one serving of dairy product provides ~300 mg of calcium, those who do not consume enough calcium from food sources may need calcium supplements to meet their daily requirement.

When purchasing calcium supplements, ensure to look for the elemental calcium content, not the total content. For instance, a pill containing 500 mg of Calcium Carbonate provides 200 mg of elemental calcium. Hence one pill in this example only provides 200 mg of calcium, not 500 mg.

Calcium is absorbed in small intestines. Not all calcium we consume will be absorbed. The amount of calcium absorbed is dependent on a number of factors such as the acidic condition in our intestines, Vitamin D level, estrogen level and the type of calcium supplement.

Different Types of Calcium Supplements

  • One important factor affecting calcium absorption is how well the pill dissolves. Try buying calcium pills of US Pharmacopeia’s standards. The “USP” on the label indicates that the calcium pill meets the USP standards of supplying adequate elemental calcium and how well it dissolves in our intestines.
  • Calcium Citrate e.g. Citracal or Solgar: Calcium is best absorbed in an acidic environment, hence calcium citrate is the best absorbed supplemental form of calcium. It does not require extra stomach acid for absorption; hence we may take it anytime in a day, even on an empty stomach. However Calcium Citrate usually provides less elemental calcium per pill, therefore one may need to take a relatively more numbers of pills per day depending to the needs. Cautions: people with acid reflux may not be able to tolerate calcium citrate.
  • Calcium Carbonate e.g. Viactiv, Tums or Caltrate: Most calcium pills in the market are in the form of calcium carbonate. It requires extra stomach acid for better absorption, hence it is best taken after meals.
  • Dolomite, Bone Meal or Oyster Shell: These naturally occurring calcium pills may contain heavy metal or lead. At the moment, calcium supplements are not tested by any regulatory agency for lead content. Therefore, it’s best to avoid.
  • Calcium Gluconate and Calcium Lactate: These types of calcium pills contain low content of elemental calcium. Hence, one may need to take a large amount of tablets to meet the calcium requirement!
  • Coral Calcium: This type of calcium is marketed for more than bone health. Its infomercial claimed that it can cure 200 human diseases. It’s indeed only Calcium Carbonate. Read Alert! Coral Calcium Supplement Scam

Nutrition 101

calcium, osteoporosis, pregnancy, supplements


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