Calcium Carbonate Is Superior to Calcium Citrate
by Michael Mooney, January, 2009
Raw materials manufacturers of calcium citrate, like many other large businesses, seek to create the best environment to sell their product, often by whatever means possible.
While we would like everyone and every company to be completely ethical, this is not the case most of the time when big business money is involved. I assert that these large companies have created a very effective deceptive campaign to sell their product by paying for medical journal studies that overstate the case for calcium citrate.
They then use these studies to influence medical doctors to prescribe calcium citrate, rather than the less expensive form, calcium carbonate. They also use media channels and advertising to delude the public into believing that their more expensive product is superior. Realize that because calcium citrate is about half as dense as calcium carbonate, calcium citrate requires twice as many tablets as calcium carbonate to give you the optimal dose, 1000 mg or more per day, that can not only stop bone loss but promote building or re-building bone density.
If you have to take twice as many tablets, they better do a very good job of convincing you that it's worth the trouble. They do, and they do the same to the doctors we trust with our health.
Unfortunately, while we want our doctors to be authorities on everything related to our health doctors are usually not the best source of nutritional advice.
One study showed that about 90 percent of medical doctors don't read the full studies, but rely on the headlines to make their decisions, and typically doctors are not well-read or trained in nutrition science. They are also visited by sales reps from companies that sell products, who can exert considerable influence on what the doctor prescribes.
The study below of postmenopausal women was conducted by Dr. Robert Heaney, who has published over 200 studies on calcium since 1968. It showed that, overall, calcium carbonate is a better choice. Calcium carbonate absorption is equal to calcium citrate, while costing about 3 to 5 times less and requiring half as many tablets to give you an optimal dose that will build or re-build bone.
This means that 1,000 of calcium carbonate can be delivered to you in just two tablets, while calcium citrate at 1,000 mg requires four tablets.
Would you rather take less or more tablets to support your optimal bone density?
Journal: Journal of the American College of Nutrition. 2001 Jun;20(3):239-46.
Title: Absorbability and cost effectiveness in calcium supplementation.
Authors: Heaney RP, Dowell MS, Bierman J, Hale CA, Bendich A. Creighton University, Osteoporosis Research Center, Omaha, Nebraska 68131, USA.
BACKGROUND: Cost-effectiveness of calcium supplementation depends not only on the cost of the product but on the efficiency of its absorption. Published cost-benefit analyses assume equal bioavailability for all calcium sources. Some published studies have suggested that there are differences in both the bioavailability and cost of the major calcium supplements.
DESIGN: Randomized four period, three-way cross-over comparing single doses of off-the-shelf commercial calcium supplements containing either calcium carbonate or calcium citrate compared with a no-load blank and with encapsulated calcium carbonate devoid of other ingredients; subjects rendered fully vitamin D-replete with 10 microg/day 25(OH)D by mouth, starting one week prior to the first test.
SUBJECTS: 24 postmenopausal women
METHODS: Pharmacokinetic analysis of the increment in serum total and ionized calcium and the decrement in serum iPTH induced by an oral calcium load, based upon multiple blood samples over a 24-hour period; measurement of the rise in urine calcium excretion. Data analyzed by repeated measures ANOVA. Cost calculations based on average retail prices of marketed products used in this study from April through October, 2000.
RESULTS: All three calcium sources (marketed calcium carbonate, encapsulated calcium carbonate and marketed calcium citrate) produced identical 24-hour time courses for the increment in total serum calcium. Thus, these were equally absorbed and had equivalent bioavailability. Urine calcium rose slightly more with the citrate than with the carbonate preparations. but the difference was not significant. Serum iPTH showed the expected depression accompanying the rise in serum calcium, and there were no significant differences between products.
CONCLUSION: Given the equivalent bioavailability of the two marketed products, the cost benefit analysis favors the less expensive carbonate product.