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College of Food, Agricultural, and Environmental Sciences


Chow Line: Magnesium plays vital role in health (for 8/21/11)

August 10, 2011

I've started taking calcium supplements to be sure I get the 1,200 milligrams recommended. I know that the supplements should include vitamin D to help the body absorb calcium, but a friend suggests I also need to make sure I get enough magnesium. Is that right? How much is enough?

Magnesium and calcium do indeed work together in very precise ratios to make sure your heart functions properly. Magnesium also plays other crucial roles in the body, helping to regulate blood sugar and blood pressure, maintaining normal nerve and muscle functions, and contributing to bone health. More than 200 enzymes in the body rely on magnesium, and the body's cells use it to help produce energy.

Although magnesium doesn't help the body absorb calcium, it is important to be sure you're getting enough of it to make sure the body has enough for all of those functions, including helping calcium do its job properly.

If you need 1,200 milligrams of calcium a day, I'm guessing you're 51 or older. The recommended amount of magnesium for those over 50 is 320 milligrams for women and 420 for men. When listed on the Nutrition Facts labels, magnesium is listed as a percentage based on a Daily Value of 400 milligrams (so, "10 percent" means the food contains 40 milligrams of magnesium).

Though magnesium deficiency isn't thought to be a problem in the typical American diet, there's no good test to measure magnesium in the blood. People over 65 tend to absorb less magnesium from food, and deficiencies could also occur in people who have problems with diabetes, who drink a lot of alcohol, or who have Crohn's disease or other conditions that affect absorption.

Good sources of magnesium include:

  • Dark-green leafy vegetables -- a half-cup of cooked spinach, for example, has 80 milligrams.
  • Seeds and nuts -- 1 ounce of almonds or cashews contains 77 milligrams; 2 tablespoons of peanut butter contain 50 milligrams.
  • Some types of fish -- 4 ounces of cooked flounder or sole contain 70 milligrams.
  • Beans -- a half-cup cooked beans contains 65 milligrams.
  • Whole grains -- 1 cup of whole-grain pasta contains 42 milligrams.

To download a list of foods from the U.S. Department of Agriculture's National Nutrient Database listed according to their magnesium content, go to

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 Julie Kennel, nutrition program manager for Ohio State University Extension and director of the Dietetic Internship Program in the Department of Human Nutrition in the College of Education and Human Ecology.

Martha Filipic
Julie Kennel