Difference Between Calcium Carbonate and Calcium Citrate

The key difference between calcium carbonate and calcium citrate is that the calcium carbonate has an alkaline basis whereas the calcium citrate has an acidic basis.

Calcium Carbonate and Calcium Citrate are two important calcium compounds. Calcium is a naturally occurring element with an atomic number of 20. We can represent it with the symbol Ca. It occurs in abundance in earth’s crust and is fifth most abundant by mass. It also exists abundantly in seawater as its ion is easily soluble in water. Two of its compounds, calcium carbonate and calcium citrate are of particular importance for us having lots of benefits for human beings. Just what the difference between calcium carbonate and calcium citrate is and how they benefit us is what this article intends to explain.

CONTENTS

1. Overview and Key Difference
2. What is Calcium Carbonate
3. What is Calcium Citrate
4. Side by Side Comparison – Calcium Carbonate vs Calcium Citrate in Tabular Form
5. Summary

What is Calcium Carbonate?

It is a compound of calcium that commonly occurs in rocks all over the world. Its chemical formula is CaHCO3, and it is the chief ingredient of shells of sea animals, egg shells, pearls and snails. Calcium found in this compound is useful as a health supplement as calcium deficiency in human beings can lead to many ailments. It reacts with acids to release carbon dioxide.

Figure 01: Calcium Carbonate as a Calcium Supplement

Moreover, when heated strongly, it releases carbon dioxide to form another oxide of calcium knows as calcium oxide or quicklime. This quicklime, when added to water forms a base that is extensively important all over the world in the chemical industry. Also, marble and limestone, both of which are used for flooring, are actually different forms of calcium carbonate. Furthermore, when water percolates through carbonate rocks, it partially dissolves these rocks and causes formations of stalactites and stalagmites.

What is Calcium Citrate?

Calcium citrate is a compound of calcium and citric acid. It is mainly useful as a food preservative, additive and sometimes also to increase the flavour of food. It is also important to soften hard water. Hence, doctors advice to take it as a calcium supplement to maintain healthy levels of calcium in our bodies.

Figure 02: Calcium Citrate as a Calcium Supplement

Furthermore, in calcium citrate, calcium is present by 21% of its mass. It is a white powder that is water soluble, as it comes from citric acid, it has a sour taste, though it is salt.

What is the Difference Between Calcium Carbonate and Calcium Citrate?

Calcium carbonate and calcium citrate are important ingredients in calcium supplements. The key difference between calcium carbonate and calcium citrate is that the calcium carbonate has an alkaline basis whereas the calcium citrate has an acidic basis. Moreover, due to this difference between calcium carbonate and calcium citrate in their chemical nature, calcium carbonate is not strongly absorbed by the stomach due to its alkalinity while calcium citrate is quickly absorbed due to its acidic nature. This is mainly because our stomach has an acidic environment and calcium absorption is very high at acidic conditions.

The below infographic tabulates the difference between calcium carbonate and calcium citrate as a side by side comparison.

Summary – Calcium Carbonate vs Calcium Citrate

Calcium carbonate and calcium citrate are important compounds as calcium supplements. But there are differences in the chemical nature of these two compounds. Hence the absorption of them is also different from each other. However, the key difference between calcium carbonate and calcium citrate is that calcium carbonate has an alkaline basis whereas calcium citrate has an acidic basis.

Reference:

1. “Calcium Carbonate: MedlinePlus Drug Information.” MedlinePlus, U.S. National Library of Medicine. Available here 
2. “Calcium Citrate.” Wikipedia, Wikimedia Foundation, 15 May 2018. Available here  

Image Courtesy:

1.”1117937″ by Airman st Class Jake Carter (CC0) via Air Force Medical Service Photos
2.”1316665829″ by Melinda (CC BY 2.0) via Flickr

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