(By 'fortified', I refer to this definition: increase the nutritive value of (food) by adding vitamins.)

Are there any differences between calcium supplements (as pills or tablets), and foods fortified with calcium (e.g., artificially added to products such as soy milk)?

Isn't the solid calcium carbonate in supplements chemically the same as aqueous calcium carbonate in fortified drinks? I'm lactose-intolerant. Alas, purely natural foods don't contain enough calcium for the Recommended Daily Intake.

Optional Reading and Addendum:

1. WebMD: "Keep in mind that there's really not that much difference between getting calcium in a supplement and calcium in food."
"Calcium-fortified foods -- such as cereals, some juices, and soy milk -- are excellent sources of the mineral, experts tell WebMD."

2. health.harvard.edu: An 8-ounce portion of off-the-shelf orange juice contains about 300 mg of calcium. The calcium in fortified soy milk also compares favorably to whole milk. Breakfast cereals (which are also fortified) contain substantial amounts of calcium, especially when combined with low-fat milk. A portion of oatmeal on its own contains just 100 mg of calcium. “But if you cut up some dried figs and add it to a bowl of oatmeal with milk, you easily get about half of what you need without having any supplements,” Dr. Hauser says.

3. NY Times Blog,   4. NY Times

Footnote: I originally posed this at Biology SE.

1 Answer 1


Calcium carbonate is largely insoluble in aqueous solutions; you need stomach acid to change it into calcium BIcarbonate, which is much more soluble.

Calcium-fortified foods are generally fortified with other calcium salts which are more soluble, such as calcium acetate, calcium lactate, or calcium gluconate, unless the food is high in acid.

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