Benefits
Bone density gains in children and teens
In an 18-month placebo-controlled trial in 94 girls aged about 12, 500 mg a day of calcium as CCM increased spine bone density more than placebo (18.7% vs 15.8%). In a 3-year trial in identical twins, 1,000 mg a day increased bone density at the forearm and spine in the 22 pairs who stayed prepubertal, but not in those going through puberty.
Slower bone loss in older women with low calcium intake
In a 2-year placebo-controlled trial in 301 postmenopausal women, 500 mg a day of calcium as CCM prevented bone loss at the hip, forearm and spine in women at least 6 years past menopause whose diets had less than 400 mg of calcium a day. It did not slow the rapid spine loss in the first 5 years after menopause.
Well-absorbed calcium form
In a double-isotope study, calcium from CCM was absorbed better than calcium from carbonate or milk, and women absorbed about 36% of the calcium in CCM-fortified orange juice and 42% from apple juice. Both studies were run by Procter & Gamble scientists and measured absorption, not bone outcomes.
Can be taken with or without food
A review of CCM research reports that, unlike calcium carbonate, CCM does not need to be taken with a meal to be absorbed, which may help older adults and people taking acid-reducing drugs. The review presents CCM very favorably and is not a systematic meta-analysis.
Used in calcium-fortified juices
Because it dissolves well, CCM is the calcium form used in some fortified fruit juices, which gives people who drink little milk another food source of calcium. The review notes that it costs more than calcium carbonate or tricalcium phosphate.
Mechanism of action
High solubility
CCM dissolves more readily than calcium carbonate, which is the proposed reason it is absorbed well and can be added to juices and other drinks.
Less dependence on stomach acid
Calcium carbonate needs stomach acid to dissolve, so it is best taken with food. CCM is already soluble, which is why the CCM review describes it as suitable with or without meals and for people with low stomach acid.
Standard calcium functions
Once absorbed, calcium from CCM is used like calcium from any source: for bone mineral, muscle contraction, nerve signaling and blood clotting.
Clinical trials
Randomized double-blind placebo-controlled trial of 500 mg a day of calcium as CCM for 18 months (Lloyd et al. 1993, JAMA)
94 girls, mean age 11.9 years, with an average diet of about 960 mg calcium a day.
Spine bone density rose 18.7% with CCM vs 15.8% with placebo, and total-body bone density 9.6% vs 8.3%. Fractures were not measured.
Double-blind placebo-controlled trial of 1,000 mg a day of calcium as CCM for 3 years, with one twin in each pair as the control (Johnston et al. 1992, N Engl J Med)
70 pairs of identical twins aged 6 to 14; 45 pairs completed the study.
In the 22 pairs who stayed prepubertal, the twin taking CCM gained more bone density at two forearm sites (3.8% and 5.1% more) and the spine (2.8% more). The 23 pairs who went through puberty or were past it saw no benefit.
Randomized double-blind placebo-controlled trial comparing 500 mg a day of calcium as CCM or calcium carbonate for 2 years (Dawson-Hughes et al. 1990, N Engl J Med)
301 healthy postmenopausal women, half with calcium intake below 400 mg a day.
In women at least 6 years past menopause with low intake, CCM prevented bone loss at the hip, forearm and spine compared with placebo, and did better than carbonate at the spine. Calcium did not slow spine loss in women within 5 years of menopause.