Cod and your kidneys
Potassium, phosphorus, protein and salt in cod, per 100 grams and per portion, and what it means when you have kidney disease. The figures come from the Norwegian food composition table.
Is cod good for your kidneys?
Yes. The Norwegian Directorate of Health recommends fish for dinner two to three times a week, and cod is a lean fish with plenty of protein. A portion of boiled cod (150 grams) gives around 33 grams of protein, 800 mg of potassium and 450 mg of phosphorus. If you have kidney disease and are not on dialysis, the portion can well be smaller, because protein should not be higher than the body needs. If you need to limit potassium, the portion size counts.
Per 100 grams
- Potassium
- 533 mgHigh potassium
- Phosphorus
- 299 mg
- Protein
- 21.8 g
- Salt
- 0.3 gLow salt
Per portion
| Portion | Potassium (mg) | Phosphorus (mg) | Protein (g) | Salt (g) |
|---|---|---|---|---|
| Portion (200 g) | 1,070 | 600 | 43.6 | 0.6 |
| Piece (85 g) | 450 | 250 | 18.5 | 0.3 |
How much potassium is in cod?
Cod: 533 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.
With less potassium
If you need to limit potassium, these foods in the same group are low in potassium, per 100 grams.
- Cod roe spread: 117 mg
How much phosphorus is in cod?
Cod: 299 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 fish and seafood
All figures per 100 grams. Tap a food to see it.
Fish and seafood (11)
| Food | Potassium (mg) | Phosphorus (mg) | Protein (g) | Salt (g) |
|---|---|---|---|---|
| Raw salmon | 451, high potassium | 227 | 19.9 | 0.1 |
| Salmon | 417, high potassium | 222 | 20.6 | 0.1 |
| Cod | 533, high potassium | 299 | 21.8 | 0.3 |
| Saithe | 559, high potassium | 333 | 22.8 | 0.3 |
| Mackerel in tomato | 503, high potassium | 149 | 11.9 | 1 |
| Prawns | 166, medium potassium | 170 | 16.6 | 1.1 |
| Fish cakes | 343, high potassium | 153 | 11.8 | 1.5 |
| Fish balls | 275, medium potassium | 136 | 8.6 | 1.4 |
| Tuna | 220, medium potassium | 206 | 24.1 | 1 |
| Pickled herring | 327, high potassium | 182 | 7.6 | 3 |
| Cod roe spread | 117, low potassium | 166 | 8 | 5.5 |
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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