You show up for your blood work like any of your other appointments with your oncologist, but this time your doctor says “your potassium is low.” If your like most people you stop and wonder what this means and ask how you can fix it. You can’t help but wonder if it was something you may have done or not done.

Potassium is lost when someone has had severe vomiting or diarrhea, which can be common with some chemotherapies, radiation to certain locations like to the stomach or small or large intestines, and even surgery to certain areas like the stomach or bowel. A potassium deficiency can also result from poor blood sugar control in diabetics, inadequate food intake, chronic alcoholism, intense exercise, or some medicines like diuretics and laxatives.

Why is potassium important?

Potassium is a significant mineral and electrolyte in the body that controls electrical activity of your cells in your heart and nervous system. It helps your cells and muscles grow, and it plays a role in controlling blood pressure and keeping bodily fluids balanced. Your kidneys regulate the level of potassium in the body day in and day out. High or low levels of potassium can both be problematic since potassium affects the way that your heart and nervous system work.

How much potassium do you need per day?

If your potassium is low, doctors will sometimes prescribe a potassium supplement and recommend eating more potassium-rich foods depending on your results. The doses of the supplements may be different depending on your labs, but generally speaking healthy adults need to get about 4,700 milligrams (mg) of potassium a day from foods. When potassium losses are increased, eating foods that are good sources of potassium can help keep the levels of potassium in your blood in a healthy range, but this may not increase as fast as taking a supplement. If you are at risk for having low levels longer term, then focusing on potassium rich foods may be key.

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Foods high in potassium

The following foods are good sources of potassium. You can include them more often if you have been advised to eat more potassium-rich foods by your health care team. These foods have between 200-700 mg of potassium per serving. For more on specific amounts you can check out the Office of Disease Prevention and Health Promotion hereOf note, boiling any of the foods listed below may reduce their potassium content.


Dried: raisins, prunes, apricots, dates, figs

Fresh: bananas, strawberries, watermelon, cantaloupe, oranges, avocado, tomatoes (or tomato products), cantaloupe, kiwi, citrus, honeydew, coconut


Fresh: spinach, beets, Brussel sprouts, winter squash, sweet potato, potatoes, kale, carrots, Brussel sprouts, okra, escarole, artichokes, asparagus, pumpkin, squash, mushrooms, broccoli


Fresh meats: turkey, fish, beef, chicken, pork


Plain yogurt, milk, cheese


Lima beans, black eyed peas, split peas, white beans, lentils, soybeans, kidney beans, pinto beans


Bran or bran products, nuts, seeds, peanut butter

Other foods

Coffee, chocolate, granola, molasses

Tips for Taking Potassium Supplements

If your doctor prescribes potassium supplements, you should take them as directed. Typically, potassium supplements are taken with about 4 to 8 ounces of water to limit any stomach irritation or laxative effect.

Take-home message

You can always ask your doctor or medical care team if you are at risk for low levels of potassium with your current cancer treatment regimen so that you can better prepare. The good news is that most people need to be eating more fruits and veggies anyway since most of us aren’t getting enough potassium in their diets. This helps you meet your 5-9 servings per day as recommended by the American Institute of Cancer Research—so it’s a win-win situation.

This post originally appeared on Survivors’ Table. It is republished with permission.