The kidney-potassium connection
People who have problems with their kidneys need to watch how much potassium they include in their diet. That is because the kidneys regulate potassium. If they aren’t working correctly, the potassium may not be flushed out of the body properly.
To minimize potassium buildup, a person with chronic kidney disease should stick to a low-potassium diet of between 1,500 and 2,000 milligrams (mg) per day. Limiting phosphorus, sodium, and fluids may also be important for people with kidney dysfunction.
Torey Jones Armul, MS, RDN, CSSD, a national spokesperson for the Academy of Nutrition and Dietetics, offers a couple of rules of thumb:
- Avoid high-potassium foods like potatoes, bananas, whole grains, milk, and tomato products.
- Watch portions on all foods.
- Be careful with coffee. The National Kidney Foundation recommends that people who should limit their potassium should limit their coffee in take to 1 cup per day
There are still plenty of nutritious, delicious, low-potassium options for people with kidney disease, Armul says. These include berries, squash, corn, rice, poultry, fish and non-dairy substitutes.
A plate of beef and potatoes – the quintessential Midwestern diet – is high in potassium. But another hearty meal, chicken and carrots, is considerably lower.
3 ounces (oz) of roast beef and half a cup of boiled potatoes would amount to 575 mg of potassium. But the same size portion of chicken and carrots? That comes to less than 500 mg. Substituting carrots for boiled cauliflowers, broccoli, or asparagus also keeps you in that ballpark.
When it comes to fish, potassium levels fall all over the line. You want to avoid high-potassium surf such as halibut, tuna, cod, and snapper. 3-oz servings can contain as much as 480 mg of potassium.
On the low end, the same amount of canned tuna has only 200 mg. Salmon, haddock, swordfish, and perch run about 300 mg per 3-oz serving.
Vandana Sheth, RDN, CDE, spokesperson for the Academy of Nutrition and Dietetics, says that some fruits are ideal for those on a low-potassium diet.
A tennis-ball sized apple or a small or medium-sized peach contain under 200 mg of potassium, as does a half-cup of berries (blackberries, blueberries, raspberries, strawberries).
You should avoid high-potassium fruits such as mangoes, bananas, papayas, pomegranates, prunes, and raisins.
Bananas are also packed with potassium. Just one medium-sized banana contains 425 mg.
While vegetables tend to contain a lot of potassium, Sheth says there are plenty of fresh vegetable options for those who need to watch their potassium levels. Veggies that contain less than 200 mg per serving include:
- asparagus (6 spears)
- broccoli (half-cup)
- carrots (half-cup cooked)
- corn (half an ear)
- yellow squash or zucchini (half-cup)
Avoid potatoes, artichokes, beans, spinach, beet greens, and tomatoes. A half-cup of dried beans or peas can contain as much as 470 mg of potassium.
Post a list of low-potassium foods on your refrigerator for easy reference, Sheth suggests.
“Take advantage of low-potassium cookbooks and free recipes found online, like the National Kidney Foundation’s My Food Coach and Kidney Cooking family recipe book,” she says.
“If you’re struggling to follow a low-potassium diet, make an appointment with a renal dietitian at a local wellness or dialysis center. A registered dietitian nutritionist who is familiar with renal disease can provide food suggestions and a meal plan specifically tailored to your lifestyle.”
Sometimes, people are forced to eat on the run. That’s okay, just be mindful of how much potassium you’re getting. An American fast-food staple is a cheeseburger and French fries. A fast-food cheeseburger contains between 225 and 400 mg of potassium.
And one small order of fries? A whopping 470 mg of potassium in just 3 oz. Just 1 oz of salted potato chips contain 465 mg.
When it comes to beverages, milk contains quite a bit of potassium. One cup of milk can contain as much as 380 mg, while chocolate milk contains 420 mg.
A half-cup of tomato or vegetable juice contains about 275 mg of potassium, so you may be better off with orange juice, which contains just 240 mg.
Loading up on pasta and rice may not be something many diet books recommend, but both are pretty low on potassium. They contain between 30 and 50 mg per half-cup. However, you should watch what you put on them. Just half a cup of tomato sauce or tomato puree can contain as much as 550 mg of potassium.
Just as it is important for people with kidney disease to not overdo potassium, you also shouldn’t go without it, either. Make sure you are getting at least some potassium in your diet. Luckily, it is easy to get potassium in a generally balanced diet.
Potassium is an essential nutrient that we use to maintain our body’s fluid and electrolyte balance, says Josh Axe, a certified nutrition specialist. It is needed for the function of several organs including the heart, kidneys and brain. Talk to your doctor and dietitian about the right amount of potassium for you.