Nutrition and Predialysis (“kidney diet”)

Nutrition is an important element in the management of chronic kidney disease. In general, for predialysis stages it is recommended that your intake (or “kidney diet”) consists of:1

  • Low amounts of protein
  • Sufficient calories
  • Low amounts of table salt (i.e. sodium)
  • Low amounts of phosphate
  • Low amounts of potassium
  • Variable amounts of calcium (depending on your individual needs)
  • Sufficient but not too much fluid

Protein and energy intake in predialysis

High amounts of protein damage the nephrons in your kidneys and thus accelerate the progression of chronic kidney disease. Therefore, protein intake should be limited at least to the recommended intake of 0.7–0.8 g/kg ideal body weight/day. If the GFR decreases below the value of 60 to 50 ml/min (stages 3 to 5), a more intense protein restriction is recommended. To prevent protein malnutrition, essential keto acids/amino acids are often taken as supplementation to protein-restricted diets. Please note: In any kind of protein restriction it is important to take in sufficient amounts of energy and other essential nutrients (e.g. minerals and vitamins).1

Other food ingredients

You should reduce your intake of table salt, because it contains sodium. By holding water in the body, sodium elevates blood pressure, which is accompanied by a higher protein excretion too. Both can damage your kidneys.1

Read more about sodium

You should also reduce your intake of phosphate, because high blood phosphate levels may cause itching and may result in losing calcium from your bones. As many protein-rich foods contain phosphate in abundance, a protein-restricted diet will help you to ingest less phosphate too.1

Read more about phosphate

It is useful to reduce the intake of potassium too, as high potassium levels in your blood may cause nausea and irregular heartbeat. Additionally to the diminished potassium elimination by your kidneys there are several other factors that may contribute to an increase in potassium blood levels.1

Read more about potassium

Particularly in early stages of chronic kidney disease, calcium blood levels in many patients are too low. Together with the high blood levels of phosphate this may contribute to the development of bone disease (renal osteodystrophy). That means bones may become fragile or painful.1

Read more about calcium

In early stages of chronic kidney disease (stage 1-4), you do not need to limit your fluid intake much as long as your urine output is normal. However, your fluid intake should not be more than 2.5 litres per day. As your kidneys become worse (stage 5) and you recognise a swelling of your ankles and feet or weight gain, you have to strongly restrict your fluid intake.1

Read more about fluid

To follow a protein-restricted diet it is necessary to eat nearly only vegetarian food.

How to implement kidney diet in every-day life

As you have to pay attention to several ingredients when changing your nutrition to a ‘kidney diet’, it is recommended that you receive training from a specialised dietician. Please ask your doctor about your individual nutrition requirements and about instructions from a dietician.1

To support you in planning your cooking, we provide some Recipes [/recipes] for a protein-restricted diet and a Food Ingredient Calculator (a database where you can check, which amounts of different ingredients your meal contains).

SOURCES

  1. D'Alessandro C, Piccoli GB et al. "Dietaly": practical issues for the nutritional management of CKD patients in Italy. BMC Nephrol 2016; 17(1): 10
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