Low Potassium Diet: What You Need to Know from a Renal Dietitian

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Has your doctor talked with you about a low-potassium diet? Have you been looking for information about kidney disease and read so much about potassium your head is spinning?

While not everyone with kidney disease needs to follow a low-potassium diet, it may be advised to you. This can be one of the most important parts of your renal diet. And as a renal dietitian, this is something I have taught for many years, both in dialysis and my private practice.

Ready to get started? Let’s dive into potassium and the low-potassium diet.

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What is Potassium?

Potassium is a very important mineral in the body that takes on a lot of important jobs. Some of those roles include:

  • Fluid balance
  • Nerve signaling
  • Heart rhythm
  • Muscle contractions

Potassium is the third most abundant mineral in our body. It is behind calcium and phosphorus. 

You can read more about potassium and other electrolytes here.

Low-Potassium Diet: what you need to know from a renal dietitian

How does kidney disease affect potassium?

When the kidneys are unable to filter enough waste products, including too much potassium, the potassium levels can rise.

Potassium Levels in the Blood

The range of potassium in our blood should be between 3.5 – 5.0 mg/dL. You can find your own results in your renal function panel or basic metabolic panel.

If there is a higher level of potassium in the blood, it is called hyperkalemia. This puts you at risk for irregular heart beats, heart attack, and sudden death.

A potassium level between 5.0 – 6.0 puts you at higher risk of heart complications.

If your potassium is over 6.0, you are at a dangerous level for your heart.

Symptoms of High Potassium

Unfortunately, symptoms of high potassium do not always occur. However, here are some symptoms you may experience from high potassium:

  • Fatigue
  • Weakness
  • Numbness or tingling
  • Nausea
  • Vomiting
  • Chest pain
  • Irregular heartbeat or pulse
  • Low pulse
  • Paralysis

In serious cases, untreated high potassium levels can cause cardiac arrest.

Symptoms of Low Potassium

Symptoms of low potassium levels are quite similar to those for high potassium. Similarly, this includes the risk of cardiac arrest.

Other symptoms of low potassium may include:

  • Constipation
  • Muscle weakness
  • Muscle spasms
  • Tingling or numbness
  • Abnormal heartbeat or pulse

Those with chronic kidney disease experience low potassium levels almost as much as high potassium levels. Similarly, having low potassium levels has been shown to cause kidney problems.

How do I Know How Much Potassium I’m Eating?

Whether or not you need to be following a low potassium diet, it’s important to know how much potassium you are consuming. This is for your best kidney health.

I highly recommend using a good food tracker like Cronometer* to see how much potassium you are eating each day. 

Cronometer* allows you to set your goals for potassium. Also, you can also track other important parts of a kidney diet like PRAL.

Low-Potassium Diet and Foods

If your kidney specialist has discussed your potassium levels with you at length and advised a low-potassium diet, here is what you need to know.

How much potassium should I have on a low potassium diet?

If your doctor and dietitian have spoken with you about limiting potassium, your restriction could be anywhere from 2,000 to 3,000 milligrams per day.

Most foods have at least some potassium. Therefore, aiming for no potassium in your diet is not safe. It is also not a solution to high potassium.

As mentioned, potassium needs will vary for every person with kidney disease. It is very important you work closely with your kidney specialist and dietitian to see how much potassium you should have each day.

To find out exactly how much potassium per day you should be eating, speak with your healthcare team.

Can I follow a low-potassium diet when I’m plant based?

Absolutely! In fact, I still encourage you to focus on getting plenty of fruits, veggies and whole grains. Even while on a low potassium diet!

The key here is focusing on the low potassium options you have, which there are plenty. Let’s dive into the different food groups and examples.

Low-Potassium Fruits and Vegetables

Even on a low potassium diet, vegetables will still be important to continue to eat. 

Keeping vegetables in your diet will allow you to continue to have more vitamins, minerals, and fiber.

Stick to ½ cup servings of fresh fruits and vegetables to help control potassium. If cooking, start with ½ cup fresh per serving. Importantly, a ½ cup cooked vegetables can be significantly higher in potassium.

Try aiming for 2-3 servings of low potassium vegetables and 1-2 servings of low potassium fruits each day. However, be sure to discuss with your doctor and dietitian for your own nutritional needs if you would like to include more.

Low-Potassium Vegetables

  • Asparagus
  • Arugula
  • Bamboo Shoots
  • Broccoli
  • Carrots
  • Cauliflower
  • Celery
  • Collard Greens
  • Cucumber
  • Eggplant
  • Green Beans
  • Kale
  • Lettuce
  • Mustard Greens
  • Onion
  • Peas
  • Peppers
  • Radicchio
  • Red Cabbage
  • Scallions
  • Summer Squash (like zucchini)
  • Tomatillo
  • Water Chestnuts
  • White Mushrooms

Low-Potassium Fruits

  • Apples
  • Applesauce
  • Apricots
  • Blueberries
  • Cherries
  • Cranberries
  • Fruit Cocktail
  • Grapes
  • Lemon
  • Lime
  • Mandarin Orange
  • Pear (Bosc)
  • Pineapple
  • Plum
  • Raspberries
  • Rhubarb
  • Strawberries
  • Tangerine
  • Watermelon

Low-Potassium Proteins

You may not think of proteins as having potassium, but they do! In fact, this may be one of your greatest benefits when reducing potassium as many need to also follow a low protein diet.

Examples of low potassium proteins include:

  • Cottage Cheese
  • Egg
  • Tofu
  • Tuna
  • Pecans
  • Seitan
  • Walnuts

Again, stick to ½ cup (¼ cup for nuts and seeds) or 3 ounce servings to keep foods lower in potassium.

Low-Potassium Grains

While it was previously believed that white bread, rice, and other simple carbohydrates are best for a low potassium diet, we now know better.

Above all, whole grains provide great nutrients to keep our heart healthy and control blood sugars.

Some examples of low-potassium grains include:

  • Barley
  • Brown Rice
  • Buckwheat
  • Bulgur
  • Oatmeal (1 packet instant, plain)
  • Pasta
  • Popcorn
  • Teff
  • Whole Wheat Bread (1 slice)
  • Wild Rice

Similar to the other food groups, keep grains to ½ cup servings. It’s good to keep in mind that grains also include protein, which makes it another source for low potassium protein in your plant-based diet!

Low-Potassium Beverages

Drinks can often cause a big rise in potassium without us realizing it. But there are many low potassium drinks you can include while following your own diet restrictions.

Examples of low potassium drinks include:

  • Apple juice
  • Coconut Milk (ready-to-drink)
  • Coffee
  • Cranberry juice (or cran-apple or cran-grape)
  • Ginger ale
  • Grape Juice
  • Lemonade
  • Oat Milk
  • Pineapple juice
  • Rice Milk
  • Tea, brewed

Be sure to keep any fluid restriction in mind when including beverages, even low-potassium ones.

Low-Potassium Snacks

When enjoying a quick bite to satisfy your hunger between meals, I always recommend starting with fruits and vegetables. 

However, if you’re looking for something else to enjoy while keeping to your low potassium diet, here are some ideas.

Check out my other article with 19+ low-sodium snacks.

How to Lower Potassium in Foods

If you’re interested in keeping some of your favorite high potassium foods in a low potassium diet, there are a few tricks in doing so.

Double-Boiling Method

The old method was thought to soak foods in warm water for a few hours or overnight. What we know now, though, is that simply soaking does not significantly reduce potassium.

To reduce potassium in root vegetables (like potatoes), the double-boil method is the preferred method.

Low Potassium Potatoes using the Double-Boil Method

  1. Thoroughly wash and peel potatoes.
  2. Cut into ½ inch cubes.
  3. Add to a large pot of cold water, making sure all pieces are completely submerged.
  4. Bring to a boil over medium-high heat, allowing to boil for 10-15 minutes.
  5. Turn off heat, drain and rinse potatoes.
  6. Rinse out the pot and refill with fresh, cold water.
  7. Add potatoes back into pot and return to a boil.
  8. Boil for another 10-15 minutes.
  9. Turn off heat, drain and rinse potatoes. Proceed to cooking however preferred.

By cooking potatoes with this method, you can reduce the potassium content by approximately 40-50%.

Mix in Low Potassium Foods with High Potassium Foods

  • Not ready to give up avocado? That’s okay! Try mixing a 1/8 avocado with some lower potassium green peas to make a lower-potassium avo-spread on a sandwich.
  • Want to have even lower potatoes after double-boiling? Mix half potatoes and half cauliflower. You can double-boil them all together to make it easier!
  • Looking for a satisfying low-potassium smoothie? Try swapping out the banana for frozen cauliflower. It’ll add more bulk to the nutrient-rich drink while cutting down on the potassium content. 
  • Craving salsa with those tortilla chips? Try a tomatillo- or corn-based salsa that can still include some ripe roma tomatoes. All while still being lower in potassium.

How Long Do I Need to Be on a Low Potassium Diet?

A low potassium diet may or may not be a life-long necessity. You and your healthcare provider should continue to monitor your potassium levels.

You may be able to start adding potassium back into your diet once your levels return to normal range. However, it is extremely important to be done under medical and dietary supervision.

Low-Potassium Diet: what you need to know from a renal dietitian

What if My Potassium is Still High, Even on a Low Potassium Diet?

Besides diet, there can be other factors that may alter your potassium balance. Before making any changes, discuss these topics with your nephrologist or prescribing physician.

Medications

Medications can have an effect on your potassium levels. It’s important you discuss medications with the prescribing doctor to find out if you should be on an alternative medication or change in dose. 

Here are some medications that can affect your potassium levels, potentially causing either high or low potassium levels:

  • ACE Inhibitors
  • Angotensin-II receptor blockers
  • Beta blockers
  • Calcium channel blockers
  • Diuretics (either potassium-sparing or potassium-wasting)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Antimicrobials
  • Beta2-receptor Agonists
  • Insulin
  • Laxatives

Potassium Binders

There is a medication that can be prescribed specifically for high potassium levels in the blood. These are known as potassium binders.

Examples of potassium binders include:

  • Sodium polystyrene sulfonate (SPS)
  • Calcium polystyrene sulfonate (CPS)
  • Veltassa (patiromer)
  • Lokelma (sodium zirconium cylosilicate)
  • kayexalate

Potassium binder prescriptions may be temporary (for a pre-determined period of time) or ongoing. As mentioned, ask your doctor and dietitian how much potassium you should be eating based on the medications you are prescribed.

Blood Sugar Control

If you have diabetes it will always be important to regulate your sugars. If you have high glucose levels in the blood, it may cause more potassium to be pulled out of the cells. This can cause acute high potassium.

Address uncontrolled blood sugars with both your endocrinologist (diabetes doctor) or primary care doctor, as well as a registered dietitian. Diabetes may require best control from both diet and medication orders.

Learn more about the renal diabetic diet here.

GI Upset

If you are experiencing frequent constipation you may find that your potassium levels are trending higher. 

On the other hand, if you have frequent diarrhea you could be losing more potassium.

Speak with your doctor and dietitian to find relief in these problems as they should not be ongoing. Determining the underlying cause of the GI upset will be the most helpful.

Bottom Line

Since potassium recommendations are based on lab results, kidney function, and dietary needs, it is important that you work with a dietitian to determine the best amount you should be eating.

A low-potassium diet can be an important way to keep your kidneys healthy, but it doesn’t mean getting rid of nutritious foods!

Aim for low-potassium fruits, veggies, and grains to keep up with adequate nutrients like fiber in the diet to prevent problems that can only aggravate potassium balance even more, like constipation and poor blood sugar control.

By determining a potassium-safe diet and using your food preferences, you can learn how to enjoy the best foods to still get the nutrients your body needs without risking the accumulation of potassium.