Haemodialysis (HD) was the first type of dialysis that was successfully used to treat renal failure, and diet has been an important part of the treatment since the beginning (more info on haemodialysis).
The average amount of time spent on haemodialysis is 10-15 hours per week. This means that for over 90% of the week the patient has little or no kidney function. It is therefore important to make some adjustments to the intake of food and fluids in order to avoid excessive accumulation of waste products and fluid between treatments.
Individual patients have different needs, so what is written here may not be exactly right for you. Renal dietitians will give advice according to your own blood test results and nutritional needs.
A small amount of protein is lost during each HD session therefore a slightly increased protein intake is usually recommended (no less than 1.1g of protein per kg of ideal body weight).
As for all renal patients, avoiding excessive salt is important. Too much salt will raise blood pressure, cause fluid retention (fluid overload or oedema), and it will make you thirsty making it difficult to stick to any fluid restriction you may have. We recommend a 'no added salt' diet. Do not use salt substitutes e.g. to salt, these contain large amounts of potassium.
On haemodialysis potassium levels change a lot between treatments. Because very high potassium levels are dangerous, most patients need to be careful not to eat too much potassium.
- If you are eating healthily, potassium is commonly a little high before dialysis and it may be a little low immediately after dialysis.
- It is generally felt that a pre-dialysis potassium of up to 6mmol/L is safe.
- No food needs to be completely avoided because of its potassium content - you must just not take too much of it and your overall diet should be considered.
- Not all patients need to limit their potassium intake. A little remaining function from your own kidneys can be a big help. Blood tests are needed to show whether you do.
Occassionally patients have low potassium levels which can also be dangerous and individual advice would be given.
Peter Quaife cartoon by kind permission of Jazz Communications, www.lightersideofdialysis.com
Fluid (liquids including water)
You can normally drink an amount of fluid equal to the volume of urine that you pass over 24hrs, plus 500ml. Whether more than this is safe for you needs to be judged for you individually. If you eat too much salt, you will not be able to keep your fluid intake down and will accumulate fluid between dialysis sessions.
Unfortunately urine output often falls after you start haemodialysis.
Foods also contain some fluid, but it is important that you eat enough to keep you well. You should receive advice on which foods contain larger amounts of fluid. If you do not produce much urine, you should expect to gain around 0.5kg of weight each day between dialysis treatments, i.e. a weight gain of 1-1.5kg since your last dialysis. Much higher weight gains mean that you are accumulating too much fluid. This is likely to damage your heart as it has to work harder and can raise your blood pressure, it can cause severe and dangerous fluid overload.
Click here to see an animation of how haemodialysis works, from the Kidney Patient Guide (Wrexham Maelor Hospital, Wales). You need Flash Player on your PC (or Mac) to see it work (links to get this free are provided).
Phosphate is not removed very well by haemodialysis unless you have very long treatments. Almost all patients need to follow a phosphate restriction of some degree, and many need to take phosphate binders with food also. The aim is to keep the phosphate level in the blood below 1.7mmol/l.
Patients on haemodialysis burn calories faster than usual, so the recommendation for calorie intake is usually slightly increased, to prevent unintentional weight loss. This is around 35 kcals/kg/ideal body weight.
A healthy diet
All renal patients are at extra risk of developing heart disease. It is important to live and eat healthily, eating a varied diet and limiting foods high in saturated fats.
Acknowledgements: The authors of this page were Elizabeth Sloan, Hazel Elliott and Susan Reed. It was first published in January 2001 and extensively revised in August 2006 then reviewed again by Susan Reed in August 2013. The date is was last modified is shown in the footer.