Calcium carbonate particle size and calcium absorption in adolescent girls
What it found
Calcium carbonate supplements helped teenage girls absorb and keep more calcium compared with a dummy pill.
Smaller particles did not work better than standard ones.
What they found
Studies in people
Absorption by particle size
A hormone test showed that calcium was actually absorbed less well from the small particles than from the large ones.
Absorption versus placebo
Girls taking the small-particle supplement absorbed more calcium than those taking the dummy pill.
Calcium retention with supplement
The small-particle supplement nearly doubled how much calcium the girls kept each day compared with the placebo. They kept 496 mg per day on the supplement and 256 mg per day on the placebo.
Retention by particle size
There was no meaningful difference in calcium kept between the small and large particles. Girls kept 349.1 mg per day with small particles and 322.0 mg per day with large ones.
What the authors conclude
- They conclude that adding calcium carbonate to the diet helps teenage girls absorb and keep more calcium compared with a placebo.
- They found no benefit to using smaller particles over the standard commercial size for improving calcium uptake.
How it was done
The researchers wanted to see if making calcium salt particles smaller could help the body take in more calcium from supplements.
Thirty-one girls aged 11 to 14 took part in two 3-week diet periods separated by a 1-week break. All ate a controlled diet providing 804 mg of calcium per day. One group of 19 girls also took about 600 mg extra calcium daily as either large or small calcium carbonate particles, while another group of 12 took small particles or a placebo.
What it can’t tell you
- We summarised it from the abstract only.
- This trial only looked at girls aged 11 to 14, so it cannot show what happens in boys, younger children or adults.
- The study lasted just three weeks per period, so longer-term effects are unknown.
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 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error