Calcium carbonate particle size and calcium absorption in teenage girls
What it found
In teenage girls, calcium carbonate supplements increased calcium retention compared with placebo, but making the particles smaller gave no advantage over standard large particles.
The authors say the small particle size did not improve absorption or retention.
What they found
Studies in people
Small vs large particles
The parathyroid hormone suppression curve showed that calcium absorption from small particle calcium carbonate was less than from large particle calcium carbonate.
Small particles vs placebo
The parathyroid hormone suppression curve showed that calcium absorption from small particle calcium carbonate was greater than from placebo.
Calcium retention vs placebo
The small particle calcium carbonate supplement increased calcium retention nearly 2-fold compared with placebo. The amounts were 496 mg a day and 256 mg a day, respectively.
Retention, small vs large
There was no significant difference in calcium retention between small and large particle size calcium carbonate. The amounts were 349.1 mg a day and 322.0 mg a day, respectively.
What the authors conclude
“Dietary supplementation with CaCO(3) is effective in increasing calcium absorption and retention compared with placebo.”
Also in their conclusions
- They conclude that dietary supplementation with calcium carbonate is effective in increasing calcium absorption and retention compared with placebo.
- They state that there is no advantage of small compared with large particle size calcium carbonate on calcium absorption and retention.
How it was done
The authors wanted to see if making calcium salt particles smaller in a supplement could increase calcium absorption.
Thirty-one girls aged 11 to 14 took part in two 3-week calcium balance periods separated by a 1-week washout. They ate a controlled diet with 804 mg of calcium a day. One group of 19 received about 600 mg a day of extra calcium as either large particle (18 μm) or small particle (13.5 μm) calcium carbonate. A second group of 12 received about 600 mg a day of calcium from small particle calcium carbonate or a placebo.
What it can’t tell you
- We summarised it from the abstract only.
- This trial was in teenage girls only, so the results may not apply to other groups.
- The study lasted a few weeks, so it cannot show what happens over a longer time.
Who paid
- Authors work at
- Purdue University, USA
The paper
- Title
- Effect of calcium carbonate particle size on calcium absorption and retention in adolescent girls
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Elble AE, Hill KM, Park CY, Martin BR, Peacock M, Weaver CM (2011). Effect of calcium carbonate particle size on calcium absorption and retention in adolescent girls. Journal of the American College of Nutrition. doi:10.1080/07315724.2011.10719957PubMed 21896874DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error