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College of Food, Agricultural, and Environmental Sciences


Chow Line: Calcium essential throughout life (3/16/12)

March 15, 2012

My doctor suggested I take a few antacid tablets every day to get additional calcium. A colleague said I should space them throughout the day instead of taking them all at once. Is that true?

It depends on how much your doctor told you to take.

It’s not easy for the body to absorb calcium. On average, the body absorbs only about 30 percent of the calcium we consume from foods or supplements. If you consume more than 500 or 600 milligrams at a time, then it’s true, the absorption rate drops to an estimated 20 percent.

You’ll still get some benefit. If you take 500 milligrams of calcium and absorb 30 percent, that’s 150 milligrams absorbed. If you take 1,000 milligrams and absorb only 20 percent, that’s 200 milligrams. But you’ll get more bang for your buck if you wait a few hours between two 500-milligram doses.

Several things can help absorption. Make sure you take calcium with vitamin D. (That’s why milk and many calcium supplements are fortified with vitamin D.) When taking supplements, liquid or chewable ones tend to be better absorbed. Also, calcium citrate can be absorbed well without food, while another form, calcium carbonate, should be taken with food for better absorption.

No matter what, getting enough calcium is essential. Muscles, nerves, blood vessels -- actually, every cell of the body -- all rely on calcium to perform basic functions. If the body doesn’t have enough calcium in its blood and other tissues, it takes calcium from your bones and teeth. That’s why it’s important to get enough calcium throughout your lifetime -- even after the teen years, the critical time for bone formation.

The recommended daily amount of calcium depends primarily on age. Teens need 1,300 milligrams a day. Adults 19-50 and men up to 70 need 1,000 milligrams a day. Women 51 and older and men 71 and older need 1,200 milligrams a day. When setting these amounts, experts have already taken into account the absorption rate of calcium, so you don’t have to worry about that.

Good food sources of calcium include dairy products such as milk, yogurt and cheese; dark green vegetables, including broccoli and kale; and calcium-fortified cereal, soy milk, juice and other foods. For more information on calcium supplements, see the fact sheet from the National Institutes of Health at

Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or

Editor: This column was reviewed by Dan Remley, field specialist for Ohio State University Extension in family nutrition and wellness.


Martha Filipic
Dan Remley