Potassium showing up at the table -- and on labels

If you’re a close reader of nutrition labels, you may have noticed that more food packages now list how much potassium they contain.

The Food and Drug Administration doesn’t require that, but “there’s both consumer and industry interest to provide potassium information on a voluntary basis,” says Robert Earl, senior director of nutrition policy at the Food Products Assn., which represents food manufacturers.

That’s because in recent years several well-regarded groups -- the U.S. Dietary Guidelines Advisory Committee, the National Academy of Sciences’ Food and Nutrition Board and the National Heart, Lung, and Blood Institute -- have underscored the health benefits of potassium and the risks of falling short.

Besides, the food industry has been criticized for adding too much salt to many products. High blood pressure is a problem that afflicts nearly one in three adults in the United States, according to the American Heart Assn. Studies show that a potassium-rich diet can help counter the blood-pressure-raising effects of too much sodium.

How much potassium do you need daily? The National Academy of Sciences says 4,700 milligrams daily is considered adequate for adults 20 and older. But men routinely consume only about two-thirds of that goal, and women get about half, according to a recent study cited in a report by the U.S. Dietary Guidelines Advisory Committee.

“Our diet is remarkably different from what we evolved on,” says Dr. Lawrence Appel, professor of medicine at Johns Hopkins Medical Institutions in Baltimore, and a member of two of the expert committees that have examined potassium. “We evolved on a low-sodium, high-potassium diet. Now we eat a high-sodium, low-potassium diet. This flip may be in part responsible for many of the [health] problems that are commonplace today.”

Besides high blood pressure, problems include stroke, kidney stones and the debilitating bone disease osteoporosis -- one of the major causes of broken bones in the elderly and a frequent reason for admission to nursing homes. Potassium protects us by blunting salt-sensitivity, regulating blood pressure, keeping the heart at a steady beat and muting calcium loss from bones.

Though you can eat food fortified with potassium, sprinkle potassium chloride on your food in place of standard table salt or use dietary supplements with potassium, “you can get all the potassium you need through foods,” Appel says. Current goals are for most adults to consume two cups of fruit daily; two and a half cups of vegetables daily; and to drink three glasses of low-fat or nonfat milk.

Naturally occurring potassium seems to best cover the health bases. Potassium chloride alone appears to protect against only salt sensitivity and high blood pressure, but not against kidney stones or bone loss.

Also, potassium chloride or potassium supplements could be harmful for those who have kidney damage or who take blood-pressure drugs known as angiotensin-converting enzyme inhibitors.

“If you have problems with kidney function or are taking medication to lower blood pressure, check with your doctor before increasing your potassium intake,” Appel says.

The more varied -- and less processed -- your diet, the better, he says.

Here are just a few potassium-rich options:

Eat a sweet potato. One baked sweet potato contains nearly 700 milligrams of potassium, twice that found in 6 ounces of orange juice.

Dig into some cooked greens. A cup of cooked spinach provides about 20% of the daily potassium intake.

Toss some white beans on your salad. And while you’re at it, add edamame, green soybeans and some tuna. All are rich sources of potassium. About half a cup of the soybeans, half a cup of white beans plus 3 ounces of tuna provides one-third of the daily adequate intake for potassium.

Snack on yogurt. An 8-ounce container of plain, low-fat yogurt has more than 500 milligrams of potassium. Add a banana and you’ll get nearly a quarter of the daily intake.

Dine on fish. Tuna, cod, halibut, clams, rockfish and rainbow trout are packed with potassium, providing about 10% of the daily intake per 3-ounce serving.

Sip tomato juice. Tomato products from juice to tomato paste, including spaghetti sauce, are rich sources of potassium, as are winter squash, apricots, peaches, prunes, cantaloupe and honeydew. Choose canned tomato products low in sodium, because the regular products are generally high in sodium.