Chelated Calcium vs. Calcium Citrate

By Brenda Keener

As we age, our bones become depleted of calcium. Calcium supplementation is one way to prevent osteoporosis or bone weakness and is recommended by doctors for many people over 50. Choosing the right supplement can be confusing, as there are many different forms of calcium. Two of the most popular forms include calcium citrate and chelated calcium.

Why Supplement?

Calcium is not just necessary for strong bones and teeth, it is also used for muscle contraction, blood vessel expansion and contraction, transmitting impulses through the nervous system and the secretion of hormones and vital enzymes. Many people do not get enough calcium or consume a lot of caffeine, alcohol or sodium, all of which interfere with calcium's absorption into the body. A lack of calcium can lead to osteoporosis, muscle cramps, spasms and dental problems, among other issues.

Calcium Citrate

Calcium carbonate used to be the preferred supplement of choice but studies have shown that calcium citrate is more "bioavailable" to the body than calcium carbonate. A study published by the "Journal of Clinical Pharmacology" used serum parathyroid hormone (PTH) suppression as one of three measures to show calcium absorption. Calcium citrate showed a 50% increase in PTH suppression over calcium carbonate, which is evidence that it is better absorbed by the body.

Chelated Calcium

Chelated calcium is a form of calcium bonded to amino acids, so that the human body will recognize it as a food and absorb it easier. Chelation improves absorption over that of other forms of calcium. Many chelated forms of calcium are proprietary blends. However, some forms are known as calcium gluconate, calcium lactate, calcium citrate and calcium citrate malate.


Calcium citrate is a form of chelated calcium and has solid studies to back up its effectiveness. More complex chelated forms are often proprietary and have little scientific evidence to support claims of higher effectiveness. Calcium citrate is far less expensive than most proprietary chelates and this is also a factor in choice.

Poor Forms of Calcium

Calcium from oyster or seafood shells is to be avoided as it may contain heavy metal contamination. Coral calcium has been claimed as the next miracle supplement. However, it is simply calcium carbonate. This does not justify the additional cost involved.

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