In the body, potassium (symbol:K) is one of the minerals and electrolytes essential for the the normal functioning of all cells. It helps ensure the proper function of the muscles and nerves, including those that control your heartbeat and breathing.

Potassium is best obtained from the food that we eat, and our bodies use the potassium it needs. The extra potassium that the body does not need is removed from the blood by the kidneys.

But if the body cannot remove the excess potassium through the urine because of other health problems that affect the function of the kidneys, such as diabetes, hypertension and heart failure, then potassium levels can increase to alarming levels, which can cause dangerous abnormal heart rhythms and even cause cardiac arrest and death.

Diets that are adequate in potassium can help control blood pressure and have been linked to a lower chance of having a stroke. But don’t go out and start taking supplements for this reason. Potassium supplements should only be used if they are prescribed by your doctor.

According to the Food and Nutrition Research Institute (FNRI) of the Department of Science and Technology (DOST), adequate intake of potassium for Filipino adults is 2,000 mg a day, taken mostly from fruits and vegetables.

Current diets, however, do not meet the recommendation of at least five servings of vegetables and fruits a day because it has just become more convenient to eat fast food or prepackaged foods. Some fruits and vegetables can also sometimes be more expensive, especially during typhoon season.

(A serving of vegetables is one cup of raw leafy vegetables or 1/2 cup raw non-leafy vegetables, or 1/2 cup cooked leafy or non-leafy vegetables. A serving of fruit is about 1/2 cup.)

Some examples of food high in potassium include:

1. Potatoes

2. Tomatoes, tomato sauce, tomato juice

3. Beans

4. Squash

5. Green leafy vegetables – spinach, bok choy

6. Okra

7. Bananas

8. Melon

9. Watermelon

10. Oranges and orange juice

11. Avocado

12. Kiwi

13. Dried fruit — prunes, raisins

14. Coconut water and meat (buko)

15. Some salt substitutes (read nutrition labels)

Patients with kidney disease should be careful not to take in too much potassium, but they shouldn’t go without it either. Those with severe kidney disease or on dialysis should still get some about 1000 mg per day. A potassium level that is too low can lead to fatigue, weakness and constipation. This deficiency can then escalate to paralysis, respiratory failure and painful gut obstruction.

The number of servings is also important. Too much of a low-potassium food makes it a high-potassium food. The recommended serving of low-potassium foods is about half a cup.

Some examples of food low in potassium:

1. Salmon (3 oz.) – 300 mg

2. Canned tuna (3 oz.) - 200 mg

3. Asparagus (6 spears) – 200 mg

4. Broccoli (half-cup) – 200 mg

5. Carrots (half-cup cooked) – 200 mg

6. Corn (half an ear) – 200 mg

7. Zucchini (half-cup) – 200 mg

8. Apple (tennis-ball size) – 200 mg

9. Grapes (half cup) – 100 mg

10. Pineapple (half cup) – 100 mg

Potassium levels can also be affected by certain medications, such as diuretics (hydrochlorothiazide, furosemide), which tend to lower potassium levels, while other medications for blood pressure (enalapril, lisinopril, ramipril, perindopril, losartan, candesartan, irbesartan) have the opposite effect and can raise potassium levels. So can common painkillers such as ibuprofen or naproxen. If you take any of these ask your doctor if your potassium levels need to be monitored.

In general, healthy potassium levels can be maintained with a balanced diet and eating the recommended number of servings for fruits and vegetables. Remember to never take potassium supplements without a doctor’s prescription, and consult with your doctor to find out the amount of potassium that’s right for you.