What is the Difference Between Calcium Carbonate and Calcium Citrate?

The main differences between calcium carbonate and calcium citrate are their composition, absorption, and recommended use:

1. Composition: Calcium carbonate is the most concentrated form of calcium, containing about 40% elemental calcium by weight. Calcium citrate, on the other hand, contains only 21% elemental calcium.
2. Absorption: Calcium citrate is absorbed more easily than calcium carbonate, with a 22-27% higher absorption rate regardless of whether taken with or without food. Calcium carbonate requires stomach acid for absorption, while calcium citrate does not.
3. Recommended Use: Calcium carbonate is generally well-tolerated, but some people may experience mild constipation or bloating. It is best taken with food, as it requires stomach acid for absorption. Calcium citrate can be taken on an empty stomach and is more readily absorbed by people who take acid-reducing heartburn medications.

Both calcium carbonate and calcium citrate can be effective calcium supplements, but the choice between them depends on individual needs and preferences. Calcium carbonate is typically more affordable and contains a higher concentration of calcium, but it requires stomach acid for absorption. Calcium citrate is more easily absorbed and can be taken without food, making it a better option for those with reduced stomach acid. It is essential to consult a registered dietitian or a doctor to determine the appropriate types, dosages, and timing of calcium supplementation for individual needs.

Comparative Table: Calcium Carbonate vs Calcium Citrate

Here is a table comparing the differences between calcium carbonate and calcium citrate:

Calcium carbonate is found in products such as Caltrate, Viactiv Calcium Chews, Os-Cal, and Tums, while calcium citrate is found in products like Citracal and GNC Calcimate Plus 800. Both types of calcium supplements have their benefits and downsides, so it's essential to consider factors such as cost, convenience, and individual tolerance when choosing between them.