Many kidney patients will hear to “stay away from potatoes” in a renal diet. As a renal dietitian, I am here to tell you that it’s not always the case. There is actually a way you can cook them well – twice, in fact – to lower potassium in potatoes significantly. No, it’s not leaching. The potato leaching method is debunked. The trick is to double-boil. In this article, we’ll cover the nutrition benefits of potatoes in a renal diet, how to properly double-boil potatoes to reduce potassium, as well as low potassium alternatives to potatoes.
Table of Contents
Potassium in the Renal Diet
The kidneys balance electrolytes in our body. This includes potassium.
However, the body can retain these electrolytes with a large loss of kidney function.
Potassium also interacts with the medications used for chronic conditions like diabetes, hypertension, heart disease, arthritis, and more by enhancing their effects or blocking them altogether.
The low potassium renal diet is for those with chronic kidney disease (CKD) with high potassium levels.
It is physician- or dietitian-ordered.
The goal is to reduce or prevent hyperkalemia (high levels of potassium in the blood) by limiting dietary potassium intake.
Therefore, including low potassium potatoes is important for a low potassium kidney patient.
Defining Low Potassium
There are a few terms and categories to look at when discussing low potassium in the diet.
This is an important review to understand the relative potassium content in potatoes.
Low Potassium Diet
The Adequate Intakes (AI) of potassium for men is 3,400 mg potassium per day and women is 2,600 mg per day.
The American Dietary Guidelines recommend adults get 4,700 milligrams of potassium per day.
A low potassium diet will be anywhere from 2,000 to 4,000 milligrams of potassium per day.
The amount will depend on each individual person including their potassium balance and kidney disease progression.
Low Potassium Food
There is no true definition of a low potassium food.
However, the general consensus is that a low potassium food should to have less than 200 mg potassium per serving.
For reference, one large (299 g) baked potato has 1,600 milligrams of potassium.
That would mean one potato can take up to 80% of a kidney patient’s daily potassium allowance. And it most definitely is not a low potassium food.
Later in this article, we’re going to cover how you can lower potassium in potatoes. That way, they will not take up such a considerable amount of a daily potassium allowance.
Nutritional Value of Potatoes
Potatoes are actually a very nutritious food, despite what some say.
They are a good source of fiber, potassium, vitamin C, vitamin B6, and magnesium.
One medium (173 grams) white potato provides:
- 159 calories
- 13 milligrams sodium
- 941 milligrams potassium
- 37 grams carbohydrate
- 4 grams fiber
- 4 grams protein
- 130 milligrams phosphorus
- 70% DV vitamin C
- 30% DV vitamin B6
- 12% DV magnesium
- 9% iron
Additionally, potatoes are low in protein and low fat which is good for the kidney patient.
Are potatoes high in phosphorus?
A medium white potato has 130 mg organic phosphorus.
While that seems high, it’s important to remember this is naturally occurring, organic phosphorus.
This makes it poorly absorbed, as little as 30% of the phosphorus.
Potassium is also present so it’s important to understand what types of potatoes have more potassium than others if your goal is to keep to a low potassium diet.
Are potatoes high in potassium?
As noted above, potatoes are a high potassium food.
However, with more than 4,000 varieties of potatoes, there are plenty of options.
It’s important to know that different varieties and preparation methods of potatoes will influence the amount of potassium in potatoes.
|Type of Potato
|Potassium in 100 grams raw (without skin)
As stated earlier, potatoes have a lot of potassium in them.
This doesn’t mean you can never eat potatoes, but you should limit how much you eat and which types.
Health Benefits of Potatoes
Potatoes provide many health benefits. They are low in fat and sodium which makes them suitable for those on low cholesterol, low sodium diet.
They are also low-calorie and even gluten-free.
Potatoes provide the following health benefits:
- Vitamin C to support your immune system
- Vitamin B6 to keep you energized
- Iron for blood health (think anemia)
Potatoes are a complex carbohydrate. This means they are digested at a slower rate.
Fiber helps lower blood sugar spikes and support healthy blood pressure.
Fiber is mostly in the skin of potatoes, like other fruits and vegetables with edible skins.
We used to think that leaching potatoes (soaking in water overnight) was effective.
However, soaking even for up to 8 hours does not effectively and consistently lower potassium in potatoes.
Double-boiling is more effective than leaching.
Double boiling is a great way to make low potassium potatoes.
One study found that double-boiling potatoes could reduce potassium content by about 50%.
Potassium in Double Boiled Potatoes
A study published in 2008 analyzed how much potassium is removed by double-boiling potatoes.
Researchers measured the potassium content of a variety of potatoes including russet, red, gold, and even purple potatoes.
The table below shows how much potassium was removed from potatoes using normal boiling and double boiling.
|Type of Potato
|mg Potassium in Raw
(per 100 grams)
|mg Potassium in Single Boil
(per 100 grams)
|mg Potassium in Double Boil
(per 100 grams)
As you can see from the table, most of the double-boiled potatoes are low potassium potatoes.
However, Yukon Gold potatoes were above the 200 mg potassium threshold even after double-boiling.
It’s important to follow the directions of how to double-boil potatoes to make them lower or low in potassium.
How to Double Boil Potatoes to Reduce Potassium
Here is the step-by-step guide to double-boiling potatoes to reduce potassium.
Prepare the Potatoes
To double boil your potatoes, first wash them well. For the lowest potassium content, peel the skins off the potato. Wash again and then pat dry.
Dice into small pieces; less than 1″ cubes. Or for maximum potassium removal, use a grater, mandoline or sharp knife to carefully slice potatoes into thin slices.
More potassium will be removed with more potato surface area contacting the water.
Add to Water
Add diced potatoes to a large pot and fill with fresh, cold water. Potatoes must be completely submerged in several inches of water.
Place on the stovetop on medium-high heat. Once boiling, allow to boil for 10-15 minutes.
Turn off heat, drain potatoes into a colander. Place potatoes back into the pot and add fresh water.
Bring water and potatoes to boil again over medium-high heat. Allow boiling again for 10-15 minutes.
Turn off heat and drain potatoes in the colander once more.
Rinse with cold water to stop the cooking process.
How to Use Double-Boiled Potatoes
Once you have double-boiled potatoes, you can cook them however you like.
If you diced the potatoes into cubes, they can be roasted in the oven or sauteed in a skillet.
Shredded potatoes are great for hash browns.
Of course, the sliced rounds can be used for scalloped potatoes.
Either shredded, diced or rounds can be used to make mashed potatoes.
A common way to use double-boiled potatoes is with mashed potatoes.
By using double-boiled potatoes, you’ll have less potassium in your mashed potato recipe compared to normal boiling.
In normal cooking, one cup of homemade mashed potatoes will have about 596 milligrams of potassium.
This is with whole milk, which also has a lot of potassium.
However, prepared mashed potatoes have even more potassium.
Ready-made mashed potatoes can have almost 700 milligrams of potassium per one-cup serving.
So if you want to have mashed potatoes, double-boiling a homemade version is a great way to include it in your renal diet.
Low Potassium Alternatives to Potatoes
There are some other foods that can be made to reduce the potassium content of your potato dishes even further.
The vegetables listed below can be prepared with double-boiled potatoes to further reduce the potassium content and make cooking easier.
Or you can simply prepare them while the potatoes are boiling and add in the final cooking step.
Cauliflower is a very versatile vegetable and has been known to work well for a lower carbohydrate, low potassium potato substitute.
A 1/2 cup of boiled cauliflower has just 88 milligrams of potassium. Yet, cauliflower still gives you one gram of fiber.
For mashed potatoes, swap half the recipes’ potatoes for cauliflower in equal portions. That way you can still enjoy potatoes, but with significantly less potassium.
If you have a recipe using sweet potatoes, try using carrots. You’ll keep the golden yellow-orange color but with less potassium.
One cooked carrot provides just 108 milligrams of potassium.
So if you’re planning on making sweet potato pie, sweet potato casserole, or even simple mashed sweet potatoes, we encourage you to try this easy substitution.
Turnips are another root vegetable that can be used with potatoes in either mashed or roasted potato recipes.
One cup (156 g) of boiled turnip cubes provides 276 milligrams of potassium with 3 grams of fiber.
And yes, this is still considered high potassium.
However, one cup (156 g) of boiled potatoes has 512 milligrams of potassium.
So using this swap will reduce the potassium content by about 50%.
If you’re a fan of roasted red potatoes, you should definitely try adding in radishes next time.
A 100-gram (approximately 1/2 cup) serving of radishes has just 233 milligrams of potassium.
In comparison, a 100-gram serving (about a 1/2 cup) of red potato has 455 milligrams of potassium.
While raw radishes may seem spicy, when roasted the flavor mellows entirely and allows for whatever herbs and spices you use to come through.
Try adding rosemary and garlic for complimentary flavors.
Canned potatoes are another lower potassium alternative to fresh potatoes.
A 1/2 cup of canned potatoes has 210 milligrams of potassium without any extra boiling.
It’s good to know that many canned fruits, vegetables, beans and legumes can have lower potassium than their fresh counterparts.
Check the label for low- or no-added salt or sugar as canned produce can have either of these added.
Summary: How to Include Potatoes in a Renal Diet
When it comes to low potassium potatoes, double boiling is a great way to help reduce the amount of potassium in your food.
Double boiling can reduce potassium content in potatoes by approximately 50%.
However, it’s important to know that potassium content in types of potatoes will vary.
Substitute or mix potatoes with other lower potassium vegetables like carrots, cauliflower, radishes, or turnips.
Hopefully, you have found this article to help you see that potatoes can absolutely fit into a renal diet. The key is to understand portions and do what is best for your own renal diet.
If you’re still unsure about your own potassium needs, working privately with a dietitian is a great way to gain confidence and understanding with your renal diet. A dietitian will also be able to tell you exactly how much potassium to include, as well as how to factor the potassium in potatoes with your diet.
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.