Mashed potatoes and your kidneys
Potassium, phosphorus, protein and salt in mashed potatoes, per 100 grams and per portion, and what it means when you have kidney disease. The figures come from the Norwegian food composition table.
Are mashed potatoes good for your kidneys?
422 mg of potassium per 100 grams is a lot. If your potassium is normal, there is no reason to avoid this food. Per portion (200 grams) you get around 840 mg of potassium and 140 mg of phosphorus. If you need to limit potassium, you will find foods with less potassium further down.
Per 100 grams
- Potassium
- 422 mgHigh potassium
- Phosphorus
- 68 mg
- Protein
- 2.4 g
- Salt
- 0.9 gMedium salt
Per portion
| Portion | Potassium (mg) | Phosphorus (mg) | Protein (g) | Salt (g) |
|---|---|---|---|---|
| Portion (200 g) | 840 | 140 | 4.8 | 1.8 |
How much potassium is in mashed potatoes?
Mashed potatoes: 422 mg of potassium per 100 grams, which is high by Metodebok's grouping: under 150 mg per 100 grams is low, 150 to 300 mg medium, and over 300 mg high. What you eat is the portion, so see the numbers per portion above.
Can cooking remove potassium?
Yes, from potatoes and vegetables. Peel them, cut them into small pieces or thin slices, boil them in plenty of water for at least ten minutes, pour the water off and finish cooking in fresh water. That removes about half of the potassium. Soaking alone does little.
How much phosphorus is in mashed potatoes?
Mashed potatoes: 68 mg of phosphorus per 100 grams. Phosphorus from plants is absorbed less than phosphorus from meat, milk and additives. Phosphate added to processed food (E338 to E341, E450 to E452) is absorbed almost completely and is not in the table, so check the ingredient list.
What does this mean for you?
How much potassium, phosphorus and protein you should eat depends on your blood tests, your stage and whether you are on dialysis. Many people with kidney disease do not need to limit potassium at all. Do not cut out fruit and vegetables unless your doctor or a clinical dietitian has asked you to.
Salt applies to everyone with kidney disease: under 5 grams a day helps blood pressure and the kidneys.
Compared with other potatoes
All figures per 100 grams. Tap a food to see it.
Potatoes (7)
| Food | Potassium (mg) | Phosphorus (mg) | Protein (g) | Salt (g) |
|---|---|---|---|---|
| Boiled new season potato | 482, high potassium | 67 | 2.1 | 0 |
| Boiled potato | 522, high potassium | 69 | 2.3 | 0 |
| Baked potato | 709, high potassium | 85 | 2.5 | 0 |
| Mashed potatoes | 422, high potassium | 68 | 2.4 | 0.9 |
| French fries | 571, high potassium | 80 | 2.5 | 0 |
| Sweet potato | 337, high potassium | 47 | 1.6 | 0.1 |
| Potato crisps | 1,220, high potassium | 127 | 6.1 | 1.1 |
Source: the Norwegian Food Composition Table 2026 (Matvaretabellen), from the Norwegian Food Safety Authority, the Directorate of Health and the University of Oslo. The potassium levels follow Metodebok. Salt is calculated from sodium (1 gram of sodium is 2.5 grams of salt).
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