Calcium Supplement: The Best Form Of Calcium To Take For Bone Health

Date: 26 April, 2004

If you take a daily calcium supplement to support bone health, the type of calcium you’re taking could make a big difference.

I asked US HSI panellist Dr. Spreen to fill us in on the calcium types, and his response will be an eye-opener for anyone who believes the advertisements that tell you antacid tablets are a good source of calcium, or for anyone who doesn’t understand that the milligrams you take are not necessarily the milligrams your body absorbs.

The line up
The question of, ‘What’s a good calcium?’ is actually somewhat complicated. But a simple place to start is by recognising that all calcium types are either organic or inorganic salts.

The inorganic forms:

  • Calcium sulphate
  • Calcium phosphate
  • Calcium carbonate

The organic forms:

  • Calcium gluconate
  • Calcium lactate
  • Calcium citrate
  • Calcium amino acid chelate (there are several of these)
  • Calcium orotate
  • Calcium aspartate
  • Calcium ascorbate

And here I’ll turn things over to Dr. Spreen: ‘Each of the above is obviously not entirely calcium… there’s a percentage of ‘the other stuff’ attached to the molecule. So, the percentage of the compound that’s ‘elemental calcium’ is an issue.

‘The most common form of supplement, by far (of all types), is calcium carbonate. It’s also the cheapest. What’s more, it also has the most elemental calcium (40% of the total molecule). Seems like that might pretty much settle the selection issue, right? Unfortunately, there are two problems with the carbonate form: 1) Like the other inorganic forms, it’s the most poorly absorbed (only 5-10%); and 2) Unlike the other inorganic forms, calcium carbonate requires (and binds) the most acid.

‘The latter problem above is appealing if you’re trying to sell an antacid product ‘that’s also good for your bones,’ but it’s very much a double-edged sword. More acid is now required for the digestion of proteins, or else
malabsorption (and indigestion!) can occur. Since you take the antacid for indigestion, you can see where this is headed.’

The good stuff
The obvious answer to the absorbency problem with the inorganic forms is to choose one of the organic forms where absorption can run anywhere from 25 percent to as high as 95 percent. But again, the details complicate the matter.

Dr. Spreen says that the best absorbed of the commercially available types are calcium orotate (90 to 95 percent absorbed), closely followed by calcium aspartate (85 percent absorbed). However, he points out that, ‘these are not only the most expensive, but they’re also the hardest to find. That means they may not be an option for many people.

‘Another really good one is calcium ascorbate, which gets you the benefit of vitamin C as the other part of the molecule, along with the fact that it’s no longer an acidic form of vitamin C… a neat solution to several problems. Again, however, it’s both expensive, and difficult to find in many places.

‘My next choice would be any of the amino acid chelates, at 65-80 percent absorption, but these are still fairly expensive, and not as easily found (though easier than the preceding two). These are probably the best compromise if you’re willing to spend just a bit more.’

Dr. Spreen notes that the best compromise of price, percentage of elemental calcium, and absorption would probably be calcium citrate. The absorption is 30 to 35 percent, and the citric acid reduces the amount of stomach acids required for absorption. For most people, calcium citrate would be the most reasonable way to go.

Bringing more to the table
But now that we’ve found an effective and economical calcium, we’re not quite out of the woods. The problem is that you can’t take calcium alone without making biochemical trouble for the body. Here’s how Dr. Spreen explained it to me:

‘Calcium is not found in nature (in edible form) without magnesium, and they therefore should always be given together. Studies show that calcium alone may even be preferentially laid down in arterial walls rather than in bones (that doesn’t sound good, does it?).

‘And you might even have an issue with higher quality supplements. The really good companies will state on the label something like ‘elemental calcium, in the form of… ‘ and tell you how many milligrams of the real thing you’re getting (though absorption is of course still an issue).

‘Unfortunately, some labels will state something like, ‘Calcium gluconate, 1000 mg.’ Are you getting 1000 milligrams of calcium? Nope, in fact you’re getting 93 milligrams of calcium; what you got was 1000 milligrams of the entire compound.

‘I wish there were an easy answer. Fortunately, most calcium supplements are not expensive, so you can take a lot of one that isn’t that well absorbed and do okay, as long as you’re getting a multi-mineral supplement that has some of the other minerals in there (minus iron, but that’s a story for another day). Read those labels carefully!’

Food boost
One obvious way to support the effectiveness of calcium supplements is to make sure you include plenty of calcium-rich foods in your diet, such as cabbage, kale, yellow, green, or waxed beans, and salmon. Foods that are high in magnesium include leafy green vegetables, whole grains, bananas, apricots, meat, beans, and nuts.

My thanks to Dr. Spreen for his informative look at calcium. If you have further questions about calcium – or any other nutrition topic – pass them along and I’ll ask Dr. Spreen to reply.

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  1. Geryl Posted March 13, 2011

    I have these Calcium gummy vitamins which are delicious but the calcium is tricalcium phosphate. Is this a good type to take. Also, the bottle recommends 2 vitamins but this only contains 500 mg calcium with 1000 IU of Vitamin D (as cholecalciferol ??) so I’ve been taking 6 of these a day for 1500 mgs of calcium and 3000 of Vit D. Does this sound OK?

  2. Dr Anon Posted August 13, 2010

    Luther – great question! The latest research is of great concern and the indications are it is the non food source highly absorbable calciums that are the worst offenders. MCHA falls into a food based source of calcium and definetly the best option.

  3. junie Posted July 24, 2010

    I’ve been taking blackmores total calcium magnesium + D3 is this the right one to take for your bones also absorbable

  4. Ken Green Posted June 18, 2010

    By test on my teeth, the best calcium from an absorption point of view, is Hydroxy-Apatite calcium. If you can find a regular supply at a reasonable cost, its the best.

  5. Luther Posted May 31, 2010

    What about the new research that indicates that these highly absorbable calcium supplements increase the risk of heart attacks by 30%? What about natural bone calcium – MCHA?

  6. JAGDISH RAJPAL Posted April 27, 2010


  7. Beverly Posted April 18, 2010

    I am taking algae calcium. I was wondering if you could tell me the absorption rate of this type of calcium.

  8. Ms. Minakshi Wanode Posted March 8, 2010

    Great. Explain in very specific way, but I need more about calcium orotate

  9. Sagar Posted February 7, 2010

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  10. Dr. Gajanand Mohata Posted January 20, 2010

    Informative about various calcium compounds – but is calcium enough or do you have to supplement with vitamin D.

  11. Mary Mangus Posted December 8, 2009

    If a supplement says the calcium is from
    oyster shell, is that negative or dangerous?

  12. Daniel Posted November 1, 2009

    Excellent. Extremely helpful and simply stated.

  13. Nick Bergren Posted September 15, 2009

    I was looking for “keywords” on Google and came across your site. I noticed you have a Google Adwords PPC campaign (didn’t click on it). In short, we can get you top 3 in the natural listings on Google for all of your main keywords. Web sites in the natural search results get more than 70% of all the clicks. We also provide response based PPC management; we can track and improve your cost per lead or cost per sale and lower your ad spend. We guarantee better results. If you want I can show you what needs to be done to your site to get you there, just need 5 minutes of your time.

  14. marie Posted August 18, 2008

    what is the best type of calcium to take, even if u don’t eat that will not upset you’re stomch

  15. gailann Posted August 16, 2008

    Helpful site!

  16. Kilda Cheung Posted August 12, 2008

    How about the absorption of Calcium lactate in percentage?

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