Just because you have to limit your potassium intake due to chronic kidney disease (CKD) doesn’t mean that you can’t continue to eat your favorite comfort foods like potatoes and yams. Here, kidney-friendly chef Anthony Valentine describes how you can cut the amount of potassium in potatoes, sweet potatoes, and yams by around 50% by double-boiling them when cooking at home.

Double-boiling v. leaching

While some sources claim that leaching potatoes and other tubers removes enough potassium to make them safe for people with CKD, research shows that leaching alone does not significantly reduce their potassium levels. Leaching involves soaking the potatoes in cold water overnight, then rinsing them before cooking or otherwise preparing them however you intended. Only when the leached potatoes were boiled did the potassium levels go down.

Boiling potatoes, specifically double-boiling them, however, can reduce a potato’s potassium content by up to 50-75%, depending on whether it is cubed or shredded. Double-boiling is a simple process. Here are the steps.

How to double-boil potatoes to reduce potassium

Beginning with a peeler, stockpot, strainer, and knife:

• Peel the potatoes. 
• Slice them into small pieces (about quarter-inch).
• Thoroughly rinse all the pieces. 
• Fill a pot with water and add the potatoes (2:1 ratio of water to potatoes). 
• Bring the pot of water to a boil.
• Drain off the water and rinse the potatoes again.
• Refill the pot with water (2:1 ratio), and boil until the potato pieces are soft but not falling apart. 
• Drain the potatoes a final time and prepare them however you wish.

Double-boiling can also reduce the levels of other nutrients such as phosphorus, which is also often limited on a kidney diet. Since some of these nutrients do remain, it’s still important to be mindful of your portion sizes when eating double-boiled potatoes and other tubers. Speak with your renal dietitian or nephrologist if you’re not sure what portion size is safe for you.

*Valentine, A. (2024). How to Leach Potassium from Potatoes. Cukebook. https://www.cukebook.org/guides/cooking/how-to-leach-potassium-from-potatoes/ 

Responsum Health closely vets all sources to ensure that we always provide you with high-quality, reliable information. We do not, however, endorse or recommend any specific providers, treatments, or products, and the use of a given source does not imply an endorsement of any provider, treatment, medication, or procedure discussed within.