Magnesium—Minor Nutrient Has Major Importance
ARS News Service, USDA, March 16, 2001

For strong bones, a healthy heart, and a smoothly functioning nervous system, our bodies rely on magnesium, an essential mineral. New studies by Agricultural Research Service scientists may reveal how much magnesium we can absorb from everyday foods and be used in fine-tuning the recommended intake of this mineral for Americans, according to research chemist Judith R. Turnlund. Good sources of magnesium include green, leafy vegetables, whole-grain breads, and nuts.

Turnlund is collaborating in magnesium research with the producers of Perrier bottled water who want to know if bottled water is a good source of magnesium. Like Turnlund's team, they need a good way to measure magnesium absorption.

The best method so far is a urine test. To evaluate this test, the researchers provided volunteers with a food or beverage spiked with a traceable form of magnesium. The scientists also injected a tiny quantity of the tracer magnesium into the volunteers' blood, then collected urine specimens about two days later.

To measure the amount of tracer magnesium in the urine samples, the scientists used an inductively coupled plasma mass spectrometer and compared the amount detected by the spectrometer to the amount given to the volunteers to calculate how much magnesium was absorbed and used.

More information on magnesium, as well as copper and molybdenum, is available in the ARS Agricultural Research magazine at http://www.ars.usda.gov/is/AR/archive/mar01/nutr0301.htm.

ARS News Service contact: Marcia Wood, phone 510/559-6070, e-mail MarciaWood@ars.usda.gov

Scientific contact: Judith R. Turnlund, ARS Western Human Nutrition Research Center, Davis, CA; phone 415/665-6274, fax: 530/752-5271, e-mail jturnlun@whnrc.usda.gov