Calcium and the Achlorhydriac

On December 13, 2009, in Minerals, by Andrea


Achlorhydria: A lack of hydrochloric acid in the digestive juices in the stomach (in technical terms, so that the pH of the stomach contents fails to fall below 4.0 under maximal stimulation). Hydrochloric acid helps digest food.

There’s quite a debate about the correct calcium to take in post a post-WLS world.  Given how very important our bones are, this is a very important topic to know about.

First off, keep in mind that the RNY, VSG, and DS are basically surgically-created achlorhydriac states.

Two studies are important to note:

From the New England Journal of Medicine:

Calcium absorption and achlorhydria

RR Recker


Defective absorption of calcium has been thought to exist in patients with achlorhydria. I compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement.

From The Journal of Nutrition:

Nutritional Aspects of Calcium Absorption1

Felix Bronner2 and Danielle Pansu*

“For this reason, calcium carbonate, when ingested alone, is a relatively poor source of calcium (Fujita et al. 1995) and, in patients with achlorhydria, is absorbed very poorly (Recker 1985)”

So it’s important to note that we should take citrate, not carbonate, as those with lowered stomach acid will not fully absorb calcium carbonate.

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