by Stephanie Legin RD, LDN
Potassium as an element is a soft, silver metal that can be cut through easily with a butter knife! Potassium functions as an electrolyte in your body. It is an abundant mineral in the body. Approximately 98% of the potassium in the body is in your cells. Your muscle cells contain about 80%, while the other 20% can be found in your bones, liver and red blood cells.
Potassium has a strong “electric” relationship with another electrolyte, sodium. Potassium is the main electrolyte in the fluid within your cells. It determines the amount of water inside the cells. Sodium is the main electrolyte in fluid outside your cells. It determines the amount of water outside the cells. The kidneys are responsible for regulating this cellular potassium/sodium balance. Your body uses the “electricity” from potassium and sodium to help balance bodily fluid levels and activate nerve impulses that affect your muscle contractions, heartbeat, and reflexes. An imbalance of potassium and sodium in the body can upset many of your body’s important functions.
Why Is Potassium a Concern If You Have CKD?
In individuals with healthy kidneys, the body is able to adapt to variable amounts of potassium consumed and maintain potassium levels within an acceptable range. If you have chronic kidney disease (CKD), your kidney function is impaired. This means your body is unable to control potassium efficiently. It can lead to high levels of potassium in the blood and, as a result, can lead to some very serious health issues:
- heart palpitations
- chest pain
- difficulty breathing
- general weakness and/or muscle weakness
- burning or prickling sensation in the extremities
- cardiac arrhythmia
- heart failure
How Much Potassium Do You Need?
Currently, the recommended Daily Value (DV) for potassium is 4,700 mg per day for individuals over the age of 18 in the US and Canada with healthy, working kidneys. This has recently changed from 3,500 mg per day with the revision of the Nutrition and Supplement Facts label. The updated food labels and DV’s must appear on food products and dietary supplements beginning in January 2020, but food manufacturers can use them now.
Chronic Kidney Disease and Potassium
Recommended daily values may be and often are different if you have chronic kidney disease. As kidney disease progresses, nutritional needs change and your doctor and healthcare team may recommend that you change your diet to protect your kidneys. Individualized potassium needs can be determined based on your stage of CKD and potassium levels obtained from routine lab testing. If you need to restrict your daily potassium intake, learning what foods contain potassium and how much is very important. Work with your doctor and registered dietitian to learn your specific daily potassium needs and understand how to stay within your daily limit.
According to the National Kidney Foundation…
- Safe zone for potassium level is 3.5 to 5.0 milliequivalents (meq) per litre
- Caution zone for potassium level is 5.1 to 6.0 milliequivalents (meq) per liter
- Danger zone for potassium level is greater than 6.0 milliequivalents (meq) per liter
What Foods Contain Potassium?
Major dietary sources of potassium are from fruits, vegetables, beans & legumes, dairy & dairy-based foods, and soy & soy-based foods.
“Low” Potassium Foods <100mg
- spaghetti/macaroni ½ cup cooked ~30mg
- white bread 1 slice ~35mg
- cheese 1 oz. ~20-55mg
- iceberg lettuce ½ cup ~43mg
- rice (white or brown) ½ cup cooked ~50mg
- egg 1 large ~65mg
- cucumbers ½ cup ~80mg
- romaine lettuce ½ cup ~81mg
- watermelon ½ cup ~85mg
- cauliflower ½ cup cooked ~88mg
- green beans ½ cup cooked ~90mg
- raspberries ½ cup ~90mg
- mandarin oranges ½ cup ~99mg
“Medium” Potassium Foods 101-200mg
- plum 1 medium fresh ~114mg
- strawberries 1 cup fresh ~120mg
- sweet bell pepper (red or green) 1 cup raw ~120mg
- onions (white/red/yellow) ½ cup raw ~ 126mg
- blueberries 1 cup fresh ~129mg
- mushrooms ½ cup fresh ~130mg
- tangerines 1 each ~140mg
- apple juice ½ cup ~148mg
- cherries 10 each ~150mg
- oatmeal 1 cup cooked ~155mg
- grapes ½ cup ~155mg
- asparagus ½ cup cooked ~155mg
- carrots ½ cup ~180mg
“High” Potassium Foods >201mg
- tomatoes (all tomato-based foods) ½ cup raw ~215mg
- oranges 1 med, fresh ~235mg, ½ cup orange juice ~250mg
- winter squash ½ cup 245mg
- nuts ¼ cup ~250mg
- beets ½ cup 260mg
- dried fruit (i.e. raisins, apricots, prunes) ¼ cup apricots ~378mg, ¼ cup raisins ~310mg
- avocados ½ cup ~355mg
- peas ½ cup ~355mg
- beans (all kinds) ½ cup ~358mg
- cantaloupe/honeydew 1/8th melon ~365mg
- milk ½ cup ~366mg
- spinach ½ cup ~400mg
- bananas 1 medium ~422mg
- soy products (i.e. soy milk, tofu, edamame) ½ cup cooked soybeans ~431mg
- dairy-based foods ½ cup pudding ~215mg, 1 cup yogurt 579mg
- potatoes (all kinds) ½ cup mashed ~ 340mg, 1 medium baked ~925mg
Keep in mind this is not an all-inclusive list of high potassium foods. There are many online reference tools to identify if a food is high in potassium or not. The USDA Food Composition Databases and Health Canada are reputable online sites to assist in identifying nutrient data in various foods.
Where’s The Potassium Info?
Unfortunately, the FDA has not mandated food manufacturers to list milligrams of potassium a food item has per serving on the current Nutrition Facts Label. Fortunately, this will be changing as the FDA has revised the Nutrition Facts label and food manufacturers will need to list how much potassium is in a food product by 2020. Until this happens, it is hard to easily identify if and how much potassium a particular food product has in it. It is mandated by the FDA to include all the ingredients in a food product. It is in this ingredient list that you can identify if a food product has had potassium additive(s) added. Look for words like potassium bicarbonate, potassium bromide, potassium chloride in the ingredient list.
Tips to Controlling Potassium in Your Diet
- Limit your intake of foods high in potassium. Work closely with your renal dietitian to determine the right amount of potassium for your individualized needs.
- Try to eat a variety of foods from different food groups in moderation in their respective appropriate portion sizes.
- The success of any kidney-friendly diet is to understand what you eat is as important as how much you eat. Almost all foods have some potassium so the serving size and the amount you consume is very important. A low potassium food can quickly turn into a high potassium food if you eat too much of it!
- Watch for hidden potassium! Many processed foods and drinks may have potassium added. Herbal or dietary supplements, protein or sports drinks, and diet bars often have this mineral.
- At this time, food labels do not have to include the amount of potassium in a food product. Even if potassium isn’t listed on the Nutrition Facts Label, it may still be in that food. Learn to read the ingredient lists on the packaging.
- Salt substitutes or “lite” salt are often potassium based. Do not use!
- Never skip dialysis treatments if you are on dialysis.
It is ok to include a high potassium vegetable in your diet on occasion. Try leaching it before preparing it to help pull some (not all) of the potassium out.
How To Leach High Potassium Vegetables
~Potatoes, Sweet Potatoes, Beets, and Winter Squash~
- Wash the vegetable thoroughly.
- Peel and slice vegetable 1/8 inch thick.
- Submerge the vegetable in cold water (so they do not darken).
- Rinse in warm water for a few seconds.
- Completely cover the vegetable with warm water. Soak for a minimum of two hours. If soaking longer, change the water every four hours.
- Discard the water used to soak the vegetable in.
- Rinse the vegetable under warm water again for a few seconds.
- Completely cover the vegetable with fresh water and get cooking!
- Wash the vegetable thoroughly.
- Peel and slice vegetable 1/8 inch thick.
- Place the vegetables in a pot and cover completely with cold water. Bring to a boil.
- Once cooked, drain and discard water.
- Put potatoes back in pot. Completely cover with cold water and bring to a boil again.
- Drain and discard water.
- Prepare as desired.
Refer to this video for a demonstration of the double boiling process.
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