When it comes to the chemistry of what we eat, we need to understand the chemistry of our own bodies. A calcium supplement is not the same from one form to the next. We never take “elemental” calcium. Instead we can take a supplement made of calcium bonded with some other chemical element(s). Which are appropriate? News reports do not tell us much about that.
Comment on “Extra Calcium May Not Do Older Women Much Good” on All Things Considered 25 May 2011. I raise questions about this study in an attempt to show how important our understanding of physiology is to the planning of studies. This was not an experiment reported on but a survey, with the lack of controls inherent in such a method of inquiry. Thus we have to be careful about the conclusions reached in the title to the study above.
Updated: June 19, 2011
NPR reporter Nancy Shute reports on studies of the benefits of calcium supplements on bones in women. A recent study in the British Medical Journal followed 61,000 Swedish women over a period of 19 years and found that they gained no benefit in their bones by taking more than 750 mg of calcium per day. Other studies in the US and other countries appear to find little benefit either, but this did not stop the Institute of Medicine from recommending that women over 50 take 1200 mg per day, regardless of no signs of bone loss. There are also problems with taking large amounts of calcium, leading to kidney stones and possibly cardiovascular problems.
My Comment Posted at NPR:
No one in these studies is addressing the form of calcium that women take in their supplements. 750 mg/day of which of the following? calcium carbonate, calcium phosphate, calcium citrate, calcium sulfate, calcium ferrate, calcium malate, calcium gluconate? Or, is coral calcium best (it is made up of many different chemical elements that appear to increase the absorbability of calcium carbonate)? Calcium doesn’t come in its ionic form, and is always combined with something. That combination will dictate calcium’s absorbability, theoretically. Its absorbability will differ from person to person.
Furthermore, these nutritional studies rarely take into account the amount of calcium that actually gets absorbed, and then how much gets distributed to the needy cells in any one person. Most probably the studies reported do not control for these aspects. I have seen absorption studies that have shown that a person needs to take twelve 500 mg capsules of calcium carbonate (oyster shell calcium) per day to achieve a level of 800 mg in the body). However, this is an average for the group studied. The variance can be pretty high, suggesting that the recommended dosage must be calculated for every person separately after many tests of absorption. There have been no tests, other than biopsies, that have been developed to determine which cells are getting the calcium that is absorbed, and I know of no doctor who has ordered these biopsies routinely. It is always assumed that every cell needing it can get it, that absorption of calcium is complete, when there is a lot of evidence suggesting that it is not (note the variance found in tests of absorption).
Finally, has anyone bothered to do a biopsy of osteoporotic bone to analyze for its fluid chemistry?–this means not just testing for the presence of calcium and phosphate, but also, the balance of calcium phosphate with other chemical elements. If all you look for is the estrogen and calcium levels, then that is the only information you will find. There are too many cases in other countries (Japan, China) where post-menopausal women do not have the level of osteoporosis found in American women. Just waving the hands and saying “genetic differences” is not an acceptable answer, especially if you have never bothered to look for all of the possible environmental causes. No genes “cause” anything, since they all must become activated by environmental signals.
For more of my thoughts and analysis of the role, physiology, and chemistry of calcium transport, uptake, and actions, see my comment on Coffee May Lower Risk Of Deadliest Prostate Cancer on Morning Edition 18 May 2011 , my extended comments on this report on Coffee and Prostate Cancer, and on Cholesterol and Heart Disease.
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© Copyright 2014 by Martha L. Hyde and https://marthalhyde.wordpress.com.