03/11/2005

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Chow Line: Be sure to get enough potassium (for 3/20/05)

Writer:

Martha Filipic
filipic.3@osu.edu
(614) 292-9833

Source:

Sharron Coplin, Human Nutrition

Why do we need potassium?

Along with sodium, calcium and magnesium, potassium helps your body maintain a normal blood pressure and heartbeat. It helps muscles contract, nerves send messages, and in general helps cells do what they are supposed to do.

Potassium also helps the body maintain a proper fluid balance. If there's too much fluid, potassium sends it to the bladder. This can lower blood pressure because as the body gets rid of excess water, excess sodium, which tends to raise blood pressure, goes along with it.

Not everyone's body reacts to sodium in the same way. Only those who are "salt sensitive" need to worry about sodium raising their blood pressure. Unfortunately, no one knows who is salt sensitive and who isn't.

Still, even salt-sensitive people can protect themselves by consuming high levels of potassium. But, unless your doctor prescribes them, there's no reason to take potassium supplements. You can get the recommended amount -- established in 2004 at 4,700 milligrams a day for people 14 or older -- directly from food, and that's what the 2005 Dietary Guidelines suggest.

A word of caution: The "Daily Value" for potassium used on Nutrition Facts labels uses the older standard of 3,500 milligrams a day, so if one of your favorite foods says it offers 10 percent of the Daily Value of potassium, it means it's giving you 350 milligrams, not 470.

Still, you'll be relieved to know that a variety of foods are high in potassium. In fact, an appendix in the Dietary Guidelines lists dozens of such foods: a five-ounce baked sweet potato contains almost 700 milligrams of potassium. A quarter-cup of tomato paste contains 664 milligrams. Five ounces of baked potato flesh has 610 milligrams. A half-cup of canned white beans contains 595 milligrams. An eight-ounce container of plain non-fat yogurt contains 579 milligrams. A half-cup of tomato puree contains 534 milligrams. Other high-potassium foods include winter squash, spinach, bananas, cantaloupe, honeydew, tomato juice, tomato sauce, cod, trout, pork chops, milk and orange juice.

For a complete list of potassium-rich foods, go the National Nutrient Database at http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl. Click on "Nutrient Lists" and scroll down to potassium.

Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, 2021 Coffey Road, Columbus, OH 43210-1044, or filipic.3@osu.edu.

Editor: This column was reviewed by Sharron Coplin, registered dietitian and Ohio State University Extension nutrition associate in the College of Human Ecology.