ESCANABA – Bananas, tomatoes, oranges, cantaloupe, peaches, spinach, Swiss chard, lima beans, potatoes – these are some of the world’s healthiest foods, in part because they are excellent sources of potassium.

Potassium is an important mineral, one of a class known as electrolytes. When dissolved in water, electrolytes conduct electricity needed for nerves and muscles to do their work. Both nerves and muscles need a good supply of potassium. The mineral plays a role in the storage of carbohydrates in the muscles for endurance activities, and it helps regulate the body’s fluid balance and blood pressure. When there is insufficient potassium, nerves and muscles fail to function as they should, and the heart (the body’s most important muscle) may lose its ability to stay in normal rhythm.

About one of every five Americans admitted to a hospital has a potassium deficiency. And a large meta-analysis published in 2011 concluded that increasing potassium intake by 1.64 grams a day could result in 1.15 million fewer stroke deaths a year worldwide while also reducing the risk of heart disease. Most Americans, unfortunately, do not consume as much potassium as they should. The Institute of Medicine, in a recent report, recommended intake of 4.7 grams a day, but most American adults consume less than half that amount…and African Americans even less.

One major benefit from consuming more potassium, according to the report, is to blunt the effect of too much sodium, another important electrolyte. Ideally, a person should consume more potassium than sodium (some experts recommend a 5:1 ratio). But Americans actually get about twice as much sodium, and this imbalance is believed to be a major factor in hypertension and other heart problems.

An enzyme-based transport mechanism known as the potassium-sodium pump is charged with the duty of moving potassium and sodium in opposite directions across cell membranes. Three sodium ions are pumped out for every two potassium ions pumped in. This pumping action is particularly important for nerve cells as they transmit impulses to working muscles.

Mainly through the kidneys, the body takes care of electrolyte imbalances. Eat too much salt, and you get thirsty. As you drink more water, the sodium is diluted, and your kidneys are signaled to hang onto water. This extra fluid in the cells, though, creates more work for the heart, and the result over time is hypertension.

Older persons and diabetics are particularly sensitive to the effects of too much salt. The Third National Health and Nutrition Survey (NHANES III) found that, over a 15-year period, higher sodium intake was associated with increased mortality from cardiovascular disease and all causes while higher potassium intake was associated with a lower risk of death. “The major implications,” wrote the authors, “are that a diet balanced in both micronutrients is important.”

Most Americans know they should cut back on their sodium intake, but few actually do so, primarily because most of the sodium in the American diet comes from processed foods rather than the salt shaker.

A seven-ounce pork chop, for example, contains 680 milligrams of potassium and 122 milligrams of sodium. A similar portion of ham, on the other hand, is not only loaded with sodium (1,850 milligrams) but has a reduced level of potassium (480 milligrams).

But it’s at least as important to get an adequate amount of potassium, which is readily obtained from fresh fruits and vegetables, whole grains, legumes and dairy products.

The DASH diet that has been found effective in reducing hypertension calls for five servings a day of fruits and five a day of vegetables plus whole grains and low-fat dairy products. Combining the DASH diet with sodium restriction has been found even more effective.

Fresh fruits such as apricots, bananas, peaches and oranges are particularly good sources of potassium and excellent alternatives to salty snacks.

It’s important, however, not to try to improve your potassium:sodium ratio by taking potassium supplements without the advice of your doctor. For stroke prevention, studies have failed to find the same benefit from potassium obtained from supplements. And too much potassium (or too little sodium) can be even more dangerous than not enough.

There is also no need to get hung up on laboriously counting milligrams of potassium. If you center your diet around fresh foods that you cook yourself, with at least five servings of fruits and vegetables, you’ll be getting the potassium you need.

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EDITOR’S NOTE: Health Update appears weekly in the Daily Press and features local health professionals. Linda Klope is a certified diabetic educator and registered dietician with OSF St. Francis Hospital & Medical Group.