Potassium is an important nutrient everyone needs, but if you have heart disease or are at risk for it, potassium takes on particular importance.

Getting plenty of potassium from food is a wise move for most people. Others, however, may need to limit potassium in their diets, including those who are taking certain blood pressure or heart medications or have kidney disease. Here's an overview of the nutrient and who should be striving to get more—or find ways to cut down.

Why Potassium Is Important

Potassium is an electrolyte with many essential jobs: It helps conduct nerve impulses and muscle contractions, regulates the flow of fluids and nutrients into and out of body cells, and helps keep your blood pressure in check—partly by countering the effects of sodium. Essentially, the level of potassium in your blood can make the difference between normal and abnormal activity in your heart and blood vessels.

Potassium does not act in a vacuum, though. It interacts with other electrolytes, including sodium. It's long been known that sodium raises blood pressure, while potassium lowers it. But it's becoming clearer that getting the right balance between sodium and potassium in the diet may be key to your heart health.

A recent study found that when it comes to the risk of developing heart disease or dying of it, the ratio of sodium to potassium in the diet is more important than the level of either mineral alone.

The study, reported in the Archives of Internal Medicine, followed more than 12,000 U.S. adults for over 15 years. During that time, 443 died of coronary heart disease (CHD) and 825 of other cardiovascular causes. The risk of dying of CHD was twice as high among people who, at the study’s start, were getting the most sodium and least potassium (versus those who had the lowest sodium-to-potassium ratio).

Of course, people who consume a lot of sodium and little potassium may be less healthy in other ways. But even when the researchers accounted for lifestyle factors like weight, smoking habits and exercise levels, and demographics like race and education, the sodium-potassium balance remained important.

How Much Potassium Do You Need?

In general, adults should get at least 4,700 mg of potassium daily, while limiting themselves to 1,500 mg of sodium. But most Americans are not meeting either goal. In the study described above, even the group with the healthiest sodium-potassium balance wasn't stellar: They typically got about 2,700 mg of sodium and 2,900 mg of potassium each day. The group with the least healthy sodium-potassium balance consumed close to 3,800 mg of sodium and about 2,700 mg of potassium.

Why is this? The main culprit is too many packaged and prepared foods. During processing, typically a large amount of salt (and, therefore, sodium) is added to foods, while any natural potassium may be stripped away. In contrast, many unprocessed whole foods—fruits and vegetables, in particular—contain adequate levels of potassium but little sodium.

In fact, the vast majority of salt in your diet comes not from your salt shaker, but from processed foods. And some of the biggest sources may surprise you: bread and rolls, prepared pasta dishes, and fresh poultry, for example. Others are less surprising—like cold cuts and cured meats, canned soups and sauces, and snack foods like chips, pretzels and popcorn. So you can optimize your potassium intake and minimize sodium intake by emphasizing fruits and vegetables, whole grains, low-fat dairy, beans, fish and lean meat in your daily diet.

Exceptions to the Rule

There are very important exceptions to what's generally recommended for most people when it comes to potassium. Some people with heart disease are at risk of accumulating too much potassium, while others may excrete too much.

Hyperkalemia

Too much potassium. Normally, the kidneys keep blood potassium within a normal range, excreting extra when necessary. But if you have kidney disease, you may not be able to efficiently eliminate excess potassium.

In addition, certain medications for high blood pressure and heart disease can boost blood potassium levels. Those include ACE inhibitors (such as enalapril, captopril and lisinopril) and angiotensinreceptor blockers (irbesartan, valsartan).

People with diabetes or heart failure are at increased risk of potassium overload, both because their kidney function may be impaired and because they commonly take the medications listed above.

Blood potassium levels should be between about 3.5 and 5 millimoles per liter (mmol/L). When levels go persistently higher, the resulting condition is called hyperkalemia. Mild hyperkalemia typically causes no symptoms, but very high potassium levels may cause problems like muscle weakness or dangerous heart rhythm.

In October 2015, the U.S. Food and Drug Administration (FDA) approved patiromer for oral suspension (Veltassa) to treat hyperkalemia. This medication is available in powder form and is mixed with water. It binds to potassium in the digestive tract, decreasing absorption of the mineral. Common side effects include constipation and diarrhea, low levels of magnesium (hypomagnesemia), nausea, and abdominal pain. Veltassa contains a boxed warning because it may decrease absorption of other oral medications.

Hypokalemia

Too little potassium. Some people clear too much potassium from their bodies. In fact, this can often happen to those on diuretics for high blood pressure—though dangerously low levels are relatively uncommon. Low potassium is known as hypokalemia. Just like its "hyper" counterpart, mild hypokalemia usually causes no clear symptoms, but more severe cases may cause muscle weakness, fatigue and potentially dangerous heart arrhythmias.

Making adjustments If you have kidney disease, heart failure or diabetes, or if you are taking any of the medications mentioned earlier, your doctor may have already talked to you about potassium. If not, you can ask him or her whether you should be striving to get more potassium into your diet—or if you should be limiting your intake instead.

If you are on a diuretic and blood work shows you have low potassium, your doctor might switch you to a potassium-sparing diuretic or recommend a potassium supplement. If your doctor does recommend reducing your potassium intake, accomplishing that can be challenging.

Potassium-rich Foods

Many potassium-rich foods are generally encouraged for a healthy diet. Here are some examples of high-potassium foods followed by healthy alternatives that you can substitute:

  • High-potassium foods (at least 250 mg/serving): wholegrain breads, wheat bran and granola; peanut butter; fruits like apricots, bananas, melon, mango, oranges and pears; vegetables like potatoes, tomatoes and tomato sauces, parsnips, cooked spinach and broccoli, and raw carrots; milk and yogurt.
  • Low-potassium foods (less than 250 mg/serving): White bread and rice; some fruits like apples, berries, grapes, pears and peaches; some vegetables, such as asparagus, green beans, cooked carrots and cabbage, cauliflower, corn, and eggplant; poultry, tuna and eggs.

Updated by Remedy Health Media

Publication Review By: Gary Gerstenblith, M.D., and Simeon Margolis, M.D., Ph.D.

Published: 04 Jul 2013

Last Modified: 27 Oct 2015