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 for you. This can be one of the most important parts of your renal diet. However, following a low-potassium diet without proper understanding and guidance can be dangerous and very hard on the kidneys. In this article, we’ll cover what a low-potassium diet is, what it isn’t, and actionable tips on how to follow a potassium restriction in a safe way that protects your kidneys.
Table of Contents
Potassium and Kidney Disease
There is a strained relationship between potassium and kidney disease.
When the kidneys are unable to filter enough, the potassium levels can rise to dangerous levels.
However, the amount of potassium that stays in the body is not just based on the kidney filtration rate.
About Potassium
Potassium is the third-most abundant mineral in our body. The top two minerals are calcium and phosphorus.
The kidneys are responsible for removing any excess potassium we don’t need through our urine.
Our bowel movements can also remove potassium. Our gut can compensate when kidneys are fully functioning. (1)
Potassium is a very important mineral in the body that takes on a lot of important jobs in the body.
Those jobs include:
- Fluid balance
- Regulating blood pressure
- Balancing cell volume
- Balancing electrolytes & ions
- Nerve signaling
- Heart rhythm
- Muscle contractions
You can read more about potassium and other electrolytes here.
Potassium is Stored in the Cell
While it’s the third most common mineral in the body, it’s the most abundant mineral found inside our cells.
Potassium is actually found in all of our body tissues.
This is one of the reasons potassium is so important.
Potassium Levels in the Blood
You potassium blood levels can be found in your renal function panel or basic metabolic panel.
Your doctor may order additional potassium bloodwork to verify the results.
The amount of potassium in our blood should be between 3.5 – 5.0 mmol/L or mg/dL.
Different labs may have slightly different levels. Therefore, it’s important to review your own potassium levels and recommended ranges.
High Potassium
In some cases, kidney patients may experience high potassium levels.
A high potassium in the blood is also known as hyperkalemia.
The Kidney Disease Improving Guidelines and Outcomes (KDIGO) define hyperkalemia as a serum potassium greater than 5.0 mmol/L. (2)
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 and other potassium roles to be compromised.
Having a very high potassium puts you at risk for irregular heart beats, heart attack, and sudden death.
Rates of High Potassium in CKD Patients
A high potassium level in the blood is uncommon for those with an estimated GFR greater than 60 ml/min/1.73m2.
However, as kidney function declines, the risk of high potassium levels increase.
A higher amount of protein leaking can also increase the risk of high potassium levels.
About 10 – 11% of Stage 4 CKD patients without diabetes can experience high potassium levels.
For those with both stage 4 CKD and diabetes, high potassium occurs in anywhere from 13 to 87% of patients.
High potassium occurs in about 25 to 35% of patients with stage 5 CKD and diabetes.
Approximately 16 to 24% in Stage 5 CKD patients without diabetes. (2)
Stage CKD | Percent of patients without Diabetes to have high potassium | Percent of patients with Diabetes to have high potassium |
---|---|---|
Stages 1-3b | About 5% or less | About 10% or less |
Stage 4 | 10 – 11% | 13 – 87% |
Stage 5 | 16 – 24% | 25 – 35% |
Causes of High Potassium
High potassium levels can be caused by:
- Poor kidney filtration
- Metabolic acidosis
- Eating more potassium than the kidneys can remove
- Medications (including some blood pressure medications)
- Thyroid imbalance
- High blood sugars / Poor blood sugar control
- Low insulin levels
- Constipation
- Improper lab handling or lab draw technique
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 in lips or extremities
- Nausea
- Vomiting
- Chest pain
- Irregular heartbeat or pulse
- Difficulty breathing
- Low pulse
- Paralysis
In serious cases, untreated high potassium levels can cause cardiac arrest. (3)
Low Potassium
While it doesn’t seem as common, low potassium levels are very much possible for kidney patients.
About 18% of kidney patients can experience low potassium levels. (4)
Low levels of potassium in the blood is known as hypokalemia. This is a potassium level of less than 3.5 mmol/L.
Low levels will generally fall below 2.5 mmol/L and can be life-threatening. (5)
Low potassium levels can happen in any stage of kidney disease, even those on dialysis.
Causes of Low Potassium
Common causes of low potassium include (5);
- Not eating enough (malnutrition)
- Excessive alcohol use
- Diabetic ketoacidosis
- Diuretics
- Diarrhea
- Excessive laxatives
- Folic acid deficiency
- Excessive sweating
- Excessive use of potassium binders
Symptoms of Low Potassium
Symptoms of low potassium levels are quite similar to those of high potassium. Similarly, this includes the risk of cardiac arrest.
Other symptoms of low potassium may include:
- Constipation
- Vomiting
- Poor appetite
- 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. (4)
Potassium Absorption Rates
Newer research has found that not all potassium is equal. This new research has changed the KDIGO perspective on managing potassium. (2)
This includes changing the foods that should be limited on a low potassium diet.
Plant-based Foods
Plants such as fruits, vegetables, nuts, seeds, and whole grains can be rich in potassium.
However, the amount of potassium absorbed may be lower than the nutritional label tells us we ingest.
It’s estimated that potassium absorption from plants is about 50 to 60%.
Animal-based Foods
Foods from animals such as meats, cheese, eggs, and dairy have a slightly higher absorption rate than plants.
It’s estimated we absorb about 70 to 90% of the potassium in these foods.
Processed Foods
Processed foods that contain potassium salts such as potassium chloride are the highest absorbed.
Foods with potassium-based ingredients have a 90% absorption rate.
Examples of potassium additives
Here are some examples of potassium-based additives you may find in ingredient lists. (6)
- Potassium citrate
- Potassium chloride (a common no-sodium salt subsitute)
- Potassium tripolyphosphate
- Dipotassium phosphate
- Dipotassium monohydrogen orthyphosphate
When to Start a Low Potassium Diet
Research shows that limiting potassium without lab evidence to indicate a low potassium diet is needed can harm health and increase the risk of death. (6)
Therefore, it is only appropriate to limit potassium when your provider has instructed you directly to do so.
Tracking Potassium
Whether or not you need to be following a low-potassium diet, it’s important to know how much potassium you are consuming.
Knowing how much potassium you are eating is a great piece of information you can bring to your doctor or dietitian for further guidance.
Using a food tracker like Cronometer can be a powerful tool to see how much potassium you are eating each day.
Cronometer allows you to set your goals for potassium.
Additionally, you can also track other important parts of a kidney diet, like PRAL.
Low Potassium Diet Guidelines
Regardless of a potassium restriction, potassium is still a very important mineral for the body.
Therefore, aiming for no potassium in your diet is not safe.
A low potassium diet restriction may be anywhere from 2,000 to 3,000 or more milligrams per day.
However, the KDIGO guidelines have no set amount to define a low potassium diet. (2)
Guidelines encourage individual diet recommendations based on a person’s health conditions, intake, labs, medications, and nutritional assessment.
It is very important you work closely with your physician and dietitian to see how much potassium you should have each day.
Defining a Low Potassium Food
While there is no set definition of a low potassium food, the general recommendation is less than 200 milligrams per serving.
This would equate to about 10% of a 2,000 milligram low potassium diet.
Low Potassium Food Groups
Below are different categories of low potassium options. While it’s not all-inclusive, it should give you plenty of ideas to start.
Low-Potassium Fruits and Vegetables
Fruits and vegetables will still be important to continue to eat on a low potassium diet.
Keeping fruits and vegetables in your diet will allow you to continue to have more vitamins, minerals, and fiber.
Stick to ½ cup servings to help control potassium.
If cooking, start with ½ cup fresh per serving. Importantly, a ½ cup of cooked vegetables can be significantly higher in potassium.
(Think about how much spinach shrinks down when you cook it.)
Aim 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 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
- Blackberries
- 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 can.
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
- Yogurt
- Egg
- Tofu
- Tuna
- Pecans
- Seitan
- Walnuts
Stick to ½ cup serving (¼ cup for nuts and seeds) or a 3-ounce serving to keep foods lower in potassium.
Many animal meats are actually considered high 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 the 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
It can be easy to fit in a cup of whole grains as whole grains are typically much lower in potassium than fruits and veggies.
It’s good to keep in mind that whole grains also include protein, which makes it another source of low-potassium protein in your plant-based diet.
Low-Potassium Drinks
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
*Avoid products with added potassium ingredients.
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.
- Rice Cake topped with cream cheese and berries or hummus and cucumbers
- Popcorn sprinkled with some nutritional yeast
- Low-Sodium Tortilla Chips
- Coconut or Almond-based Yogurt
- Pretzels with hummus or strawberries
Check out our other article with a ton of low-sodium snack options.
Low Potassium Sample Menu
Here’s an example of what a low-potassium day can look like.
Breakfast: Peanut butter bagel with 1/2 cup mixed berries + coffee with kidney-friendly creamer
Lunch: Quinoa salad with chickpeas, shredded carrots, spinach, and shallots
Snack: Granola over Coconut yogurt
Dinner: Roasted chickpea tacos with avocado-lime crema
Snack: Rice Krispy Treat
Low Potassium Swaps
Many high-potassium foods are very enjoyable and can still be a part of a low-potassium diet. Here are some tips to enjoy foods on a potassium restriction.
- Not ready to give up avocado? Mash a quarter of a small avocado with some lower-potassium cooked and cooled 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. This will add more volume 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.
Plant-Based and Low Potassium
Did you know that it’s still possible to be on a low potassium diet and plant-based?
In fact, it is still encouraged 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, of which there are plenty.
Let’s dive into the different food groups and examples.
How long do I have to be on a low potassium diet?
This will need to be answered by your doctor or dietitian.
The good news is that a low potassium diet does not always need to be followed forever.
As mentioned above, tracking labs is the best way to determine if and when a low potassium diet is needed.
Additionally, tracking dietary intake of potassium can provide further guidance on if a reduction in potassium in your diet is warranted.
Other Considerations for High Potassium Levels
Besides diet, there can be other factors that may alter your potassium balance.
Therefore, it’s important to discuss with your physician the other potential causes that could be raising your potassium.
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. (7)
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.
Gut Health
Our gut removes about 10% of the potassium we eat. (1) Therefore, a healthy gut is key to helping balance potassium levels.
Constipation can prevent the body from removing potassium. Therefore, this can cause high potassium levels.
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.
On the other hand, if you have frequent diarrhea you could be losing more potassium.
Summary
Since potassium recommendations are based on lab results, kidney function, and dietary needs, it is important to work with a dietitian to determine the best amount you should be eating.
While there is no set definition for how much potassium to include in a low potassium diet, it can range anywhere from 2,000 to 3,000+ milligrams per day. It must only be followed if your doctor or dietitian gives you specific instructions to limit your potassium.
A low potassium food is typically defined as 200 milligrams or less per serving. And while a low potassium diet can be an important way to keep you 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. This helps prevent problems that can only aggravate potassium balance even more, like constipation and poor blood sugar control.
Use a food tracker like Cronometer to see your daily potassium intake. Share this with your provider to get more feedback and monitor your potassium levels.
Take our free class
Are you unfamiliar with Cronometer? Sign up for our free class to get started.
Jen Hernandez is a registered dietitian and board-certified specialist in renal nutrition. She has nearly a decade of experience with kidney disease patients in all stages - from stage 1 through kidney transplant. Jen writes on the blog of Plant-Powered Kidneys to help reach and teach more kidney patients about how they can enjoy more foods in a plant-based diet while protecting kidney health.