Editorial Commentary in regard to manuscript: “Indentifying Risk Factors for Osteoporosis in Young Women”

In a typical US diet, men and women over the age of 50 consume approximately 600mg to 700mg of dietary calcium which is less than the current intake recommendations of 1200mg of calcium (plus 800 to 1000 IU per day of Vitamin D for enhanced absorption).1-4 First line recommendations for increasing calcium are through the diet; however, if this cannot be achieved then supplementation becomes necessary.2,3 It is important to recognize the potential for interactions with prescription medications, as well as decreased absorption of calcium supplements by the prescription medications themselves. In addition to interactions, supplements may increase risks or manifestations of other diseases or disorders, and therefore must be carefully monitored to remain beneficial to patient care and outcomes.1

Examples of counseling that must occur include the use of antacids, which can cause increases in urinary calcium excretion. Similarly, mineral oil and stimulant laxatives can lead to decreased calcium absorption, limiting the benefits of supplementation compared to the cost.2,3 Some patients may require the use of glucocorticoids, which may cause calcium depletion and increase further risks of fracture.2,3 Knowing all the medications your patient is taking (both prescription and non-prescription), as well as herbals and supplements, will increase the likelihood of successful treatment outcomes and promote safe medication use.4

Calcium carbonate and calcium citrate are common forms of supplements, and can be found along with calcium gluconate, lactate and phosphate in fortified foods and other products.3 Although calcium carbonate is more commonly available, both calcium carbonate and calcium citrate are both well absorbed.2 The body absorbs calcium carbonate most efficiently when the supplement is consumed with food, whereas in the event there are reduced levels of stomach acid, calcium citrate is more easily absorbed.2 Calcium citrate is commonly recommended, as is it equally efficacious as a supplement whether it is taken with or without food, increasing its ease in dosing and therapeutic flexibility.1-3

The essential differences among calcium are tied to the percentage weight or elemental absorptive levels of calcium. Calcium carbonate is 40% calcium by weight, where calcium citrate is only 21%.1,3,4 Elemental calcium in listed in the Supplemental Facts panel of labels, so calculating calcium is no longer necessary when determining doses per day. The percentage of calcium that is absorbed is dependent on the amount of elemental calcium consumed. Thus, the amount of tablets needed to acquire adequate intake of elemental calcium influences the supplement chosen. As "per dose” amounts of calcium increase, the actual percentage of absorption decreases. Absorption of calcium is reported to be highest in doses < 500mg which translates into the need for multiple doses along with Vitamin D, and additional minerals including magnesium and zinc.2,3

When selecting a calcium supplement, it is important to consider which formulation is safest for your patient, as well as the serving size required to achieve optimal elemental calcium intake levels. You must consider the amount of calcium and its equivalent elemental amount, as well as the number of doses of tablets, chews, or packets needed "per serving” to achieve the recommended amount. Unfortunately, this can range from single to multiple required doses and often impacts pill burden, adherence and costs of supplementation. For example, formulations of calcium carbonate supplements range from 200mg of elemental calcium per tablet/chew (TUMS® or Rolaids®) to 500mg of elemental calcium per tablet/chew (Caltrate®, Os-Cal®, Viactive®), and even higher doses of 750mg or more.5,6 This is similar for supplements containing calcium citrate which range from approximately 250mg elemental calcium per tablet (CitriCal®) to 400mg elemental calcium (NutraCal™ powder packet), again requiring multiple doses per day.7,8


  1. http://www.nof.org/sites/default/files/pdfs/NOF_ClinicianGuide2009_v7.pdf. Accessed August 8, 2011
  2. http://www.nof.org/professionals/clinical-guidelines. Accessed August 8, 2011
  3. http://ods.od.nih.gov/factsheets/Calcium/. Accessed August 8, 2011
  4. http://jaxmed.com/articles/medications/calcium.htm. Accessed August 8, 2011
  5. http://www.calciuminfo.com/index.aspx. Accessed August 8, 2011
  6. http://www.rolaids.com/page.jhtml?id=rolaids/include/regular_strength_tab.inc. Accessed August 8, 2011
  7. http://citracal.com/en/about-citracal/citracal-regular/. Accessed August 8, 2011
  8. http://www.nutracal.com/compare-calcium.html. Accessed August 8, 2011


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