Three Tips To Optimize The Absorption of Oral Calcium Supplements
Calcium is the most abundant mineral in the human body. In addition to its role in building and maintaining bone and teeth structure, calcium is also important for other physiologic functions among others, muscles contraction, blood coagulation and the regulation of nerve impulses(1).
The only source of calcium is food. Your doctor may prescribe calcium supplements if you fail to have adequate dietary intake, you have some diseases, in combination with some medications, or if you belong to a specific age group or population. But how to get the best of your calcium supplements? Here are some advices to enhance the absorption of calcium.
Take it in smaller doses
To enhance the absorption of calcium it’s recommended to take it in doses of 500mg of elemental calcium at a time. Therefore you have to split your high dose of calcium into smaller doses and take them throughout the day. A higher dose wouldn’t be efficiently absorbed in fact, some studies suggest that the excess may accumulate in the body’s tissues causing side effects.
Note that there are many forms of calcium salts in the market and not all forms contain the same amount of elemental calcium. The two most common forms are:
Calcium carbonate: 40% of elemental calcium
Calcium citrate: 21% of elemental calcium(2)
You don’t need to think a lot about how many elemental calcium in a pill, the amount of elemental calcium is generally indicated on the outer package of the brand you are using.
Avoid Calcium-Food Interaction
Take the carbonate form with food and the citrate without regard to meals. Calcium carbonate is an antacid, carbonate in fact reacts with the acid of the stomach to neutralize it, and this same reaction is responsible of releasing the salt containing calcium that will be absorbed. Food increases the absorption of calcium by10-30% in the calcium carbonate form, whereas it has no effect on the absorption of calcium citrate.(3)
Avoid oxalate rich foods: oxalate is a natural compound (soy; green, leafy vegetables such as spinach; animal protein), it binds to calcium to form a calcium_oxalate compound that’s not absorbed in the digestive tube, but eliminated in the stool.(4)
Your pharmacist advice: don’t stress on avoiding a good meal of oxalate containing food, remember u can always shift the timing of your pill. Taking your pill 2 hours after the meal will prevent this interaction. Don’t forget to distance your calcium pill from your iron and zinc ones!
Avoid calcium-drug interaction!!!
Calcium can interact with too many drugs some of the serious interactions are listed below! Always let your health care professional know that you are taking calcium pills before the prescription of a new treatment.
- Digitalis: digoxin: due to the risk of developing hypercalcemia and a subsequent cardiac arrhythmia, co administration of oral calcium acetate is not recommended in patients receiving digitalis.
- Some antiretroviral drugs (drugs against HIV): bictegravir, raltegravir, baloxavir: the absorption of these medications may be decreased if they are taken with calcium supplements. Solution: always refer to your health care provider: sometimes taking both pills simultaneously with food is recommended (bictegravir).Other times you have to separate your calcium pills from your antiretroviral drugs by many hours! All depend on the type of calcium, the generic of antiretroviral and or if you are at fasting condition or not.
- Antibiotics: the most known calcium antibiotic interaction is with tetracyclin, minocycline, doxycicline, omadacycline, sarecycline administer the antibiotic two hours before or two hours after your calcium pill or after a meal rich in dairy product.
- Phenytoin: used for the treatment of seizures. In combination with calcium, phenytoin absorption is decreased. Take it two hours before or two hours after your calcium pill.(4)
References
1. Calcium I of M (US) C to RDRI for VD and, Ross AC, Taylor CL, Yaktine AL, Valle HBD. Overview of Calcium [Internet]. Dietary Reference Intakes for Calcium and Vitamin D. National Academies Press (US); 2011 [cited 2022 Aug 19]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK56060/
2. Drug Result Page – In-Depth Answers – Dosing/Administration – Administration [Internet]. [cited 2022 Aug 19]. Available from: https://www.micromedexsolutions.com/micromedex2/librarian/CS/C331B2/ND_PR/evidencexpert/ND_P/evidencexpert/DUPLICATIONSHIELDSYNC/EC5A5E/ND_PG/evidencexpert/ND_B/evidencexpert/ND_AppProduct/evidencexpert/ND_T/evidencexpert/PFActionId/evidencexpert.DoIntegratedSearch?SearchTerm=calcium%20carbonate&UserSearchTerm=calcium%20carbonate&SearchFilter=filterNone&navitem=searchALL#
3. Fritz K, Taylor K, Parmar M. Calcium Carbonate. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2022 Aug 19]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK562303/
4. Drug Interactions results – MICROMEDEX [Internet]. [cited 2022 Aug 19]. Available from: https://www.micromedexsolutions.com/micromedex2/librarian/PFDefaultActionId/evidencexpert.ShowDrugInteractionsResults