Healthy eating on peritoneal dialysis (PD)

One of the normal functions of the kidneys is to rid the body of waste products.

When the kidneys are not working properly, these waste products can build up to harmful levels and make you unwell. The level of waste products in your blood can be affected by the foods that you eat.

Dialysis will filter unwanted products out of your blood, and together with the diet will help to keep your blood levels under control and help to keep you well.

Peritoneal dialysis (PD) refers to two similar treatments; continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) (which also includes assisted APD to certain patient groups). Both types of dialysis remove waste products continually through the day and / or night.

If you have been on any dietary restrictions before starting dialysis, the constant removal of wastes by PD means that you can have more freedom in your food intake. You may also find that your appetite increases.

As well as removing waste products, the dialysis fluid also removes some goodness from you; therefore it is important that you eat well.

The information in this sheet will help you to eat sensibly and well on PD.

Guidelines for healthy eating on PD

1. Protein

Protein is lost during the bag exchanges on PD. To make sure that this protein is replaced, you should follow these guidelines:

• Eat . . . . . . . . . meat, fish or poultry per day. It may be easier to eat this as two or three portions for example, . . . . . . . . . . and . . . . . . . . . . .
• Milk - try to have ½ pint per day (this must be included in your fluid allowance).

Eggs and cheese are valuable sources of protein. However, they are also rich sources of phosphate. If your phosphate level is raised, you should follow the guidelines in the phosphate section below.

If your appetite is good, eating these amounts of high protein foods should cause no problems. However, when you first start on PD or if you are unwell, you may find it difficult to manage. It may be necessary for you to take protein supplements. The renal dietitian will advise you if necessary and arrange these for you on prescription.

If you have an infection or peritonitis you may lose more protein in your dialysis fluid than usual, so you should aim to increase your protein intake. If your appetite is poor or you suffer nausea and sickness, you should contact the renal dietitian, who will provide you with advice and, if necessary, protein supplements.

2. Energy (calories)

It is important to have an adequate intake of energy to obtain all the goodness from your food. Bread, cereals, rice, pasta and potatoes are valuable sources of energy, vitamins, minerals and fibre and should be included in your diet at each meal.

The dialysis fluid in PD contains glucose (a type of sugar). Some of this is absorbed into the body during the dialysis and provides you with a number of calories. This may lead to weight gain, particularly if your appetite is good and you are eating large amounts of sugary and fatty foods. You will also need to be aware of this if you have diabetes.

If you find that you are gaining too much weight, contact the dietitian, who will advise you on the necessary changes you need to make to your diet.

It is advisable to use as little fat as possible in cooking since PD may lead to high levels of fat in your blood. You may find the following points useful in trying to reduce your fat intake.

• Always cut excess fat off meat before cooking.
• Brown meat and mince in non-stick frying pan or in a microwave before using in casseroles, stews etc, in order to remove some 'hidden' fat.
• Look out for low fat alternatives to some very high fat foods, for example skimmed milk, low fat spreads and low fat cheeses.
• Avoid eating too many fatty foods, such as chips, roast potatoes, pastries, Yorkshire puddings, dumplings etc.
• Try to choose fats from vegetables (polyunsaturated) sources, for example corn, sunflower, rapeseed or olive oils which have less effect on blood fat (cholesterol).
• Avoid fats from animal (saturated) sources such as butter, lard and dripping.

3. Fibre

It is advisable to have a high fibre intake on PD since:

• constipation can be an uncomfortable problem and can also make draining out difficult
• fibre will help to prevent raised blood fat levels
• fibre will help control your weight, since it fills you up and contains very few calories

The basic message is to 'swap white for brown', for example:

• white bread - swap for wholemeal bread
• Cornflakes / Rice Krispies - swap for Branflakes / Weetabix
• white rice / pasta - swap for brown rice / wholemeal pasta

Other high fibre breakfast cereals include Shredded Wheat, porridge, Puffed Wheat. Beware of cereals containing lots of dried fruit and nuts, especially muesli, since these are often high in sugar, calories and potassium (see the section on potassium below).

If you are still experiencing problems with constipation, please discuss this issue further with the PD staff or the renal dietitian. There are many suitable medicines which you can take to help ease constipation.

4. Potassium

PD removes some potassium from your blood. However, your potassium level can still rise if you eat a lot of high potassium foods. A high potassium level can be fatal.

Potassium is found in many foods, but mainly in fruits, vegetables and milk. All vegetables and potatoes must be boiled in plenty of water and should not be steamed, microwaved or pressure cooked.

Although you can eat all foods on PD, you may still need to take great care with high potassium foods. The foods listed below are some of the foods rich in potassium; you may eat foods from this list occasionally, but you should make sure that they are not taken more than once a day:

• oranges, bananas, melon and apricots
• dried fruit and anything containing dried fruit
• baked beans, butter beans, lentils, broad beans and other dried peas and beans, mushrooms
• potato crisps, frozen chips, oven chips, shop bought chips
• tomatoes
• pure fruit and vegetable juices, including the juice from tinned fruit
• tinned and packet soups
• instant coffee and milky bedtime drinks such as Horlicks, Ovaltine and Bournvita
• chocolate, toffee, fudge, liquorice, fruit gums and marzipan
• nuts and peanut butter
• soya products
• wines, sherry, beers, lagers and cider
• salt substitutes, for example Lo-Salt

If your potassium level remains high, the dietitian will advise you on further changes to make to your diet.

5. Sodium / salt

Too much salt in your diet can make you thirsty and make your blood pressure more difficult to control.

It is preferable to not use any salt in your diet but if your appetite is poor, a little salt may be used in cooking. Try not to add any at the table unless you are advised to.

If you have problems with fluid retention and/or your blood pressure is high, cut down your intake of the salty foods listed below:

• bacon, ham, sausages, tinned meats and tinned fish
• vegetables tinned in salt water
• cheese
• soups, Oxo, Bovril, Marmite, pickles, sauces & ketchups
• salted crisps and nuts, peanut butter
• chinese food, soy sauce

Pepper, herbs and spices can be used to flavour your food. Mustard, mint sauce and cranberry jelly are also suitable.

6. Fluid

As a renal patient on dialysis, you may not pass much urine. Dialysis removes some fluid, but there is still a risk that this can build up.

You should follow a fluid restriction, as advised. As a general rule you will be allowed your urine output plus an additional 700ml daily.

If you drink too much you may become overloaded with fluid. This puts extra stress on your heart and can also make breathing more difficult. You may also develop coughing, swelling of your feet and ankles and high blood pressure.

The following fluids need to be counted in your allowance:

• tea
• coffee
• water
• milk
• soft drinks, squashes
• wines*, spirits, beers*
• fruit juices* and soup*

* These fluids are high in potassium and are best avoided if your potassium level is high.

Remember that foods also contain some fluid; for example, jelly sauces and gravies.

If you are still having problems with your fluid retention, please contact the dietitian, who will provide you with a more detailed list of fluid containing foods.

7. Phosphate

A high phosphate level causes calcium to leave the bones and make them weaker. It can also lead to problems with your soft tissues, for example hands and eyes, and over a long time the heart, lungs, brain and blood vessels may also become damaged.

If the phosphate level in your blood is high, the following foods need to be restricted or avoided:

• Cheese: no more than 4oz per week. 1oz hard cheese may be exchanged for 2oz cottage cheese or 4oz cream cheese.
• Milk: limit to ½ pint per day maximum.
• Eggs: no more than two to three per week. This should include any eggs used in cooking.
• Offal: liver, kidney, etc – allow occasionally such as once monthly.
• Veal, game.
• Nuts.
• Ice cream.
• Milky drinks, malted drinks (unless used from allowance above).
• Oily fish, such as herrings, mackerel, kippers.

Try not to eat eggs and cheese on the same day.

Phosphate binders

You may be prescribed phosphate binders. During digestion, these grab hold of the phosphate in your food, preventing your body from absorbing some of it. They need to mix with as much food as possible, so if you take them too early, too late or do not chew them (if applicable) the binders will not work properly and your phosphate level will rise. See the table below for how to take your phosphate binder.

Types of phosphate binders used

The type of binder and amount to take will be advised in conjunction with the PD nurse, renal dietitian and doctor. Phosphate binders should be taken with all meals; they may also need to be taken with snacks. If you are experiencing side effects with your current binder (nausea, wind, constipation or diarrhoea) there are a wide range of available alternatives; discuss with your renal professional.

Phosphate binders should not be taken at the same time as iron tablets; take your phosphate binder at the meal time and delay your oral iron tablet until one hour after the meal.

How to take your phosphate binders

Fosrenol (lanthanum carbonate)

Take just after meals.

• Tablet form – chew.
• Powder form – either take directly from the packet or mix with a small amount of food.

Osvaren (calcium acetate and magnesium carbonate)

Swallow before meals.

Phosex (calcium acetate)

Swallow just before or during meals.

Renagel (sevelamer hydrochloride)

Swallow just before or during meals.

Renvela (sevelamer carbonate)

Take during meals.

• Tablet form – swallow.
• Powder form – mix with 60ml cold water and drink.

Velphoro (sucroferric oxyhydroxide)

Chew tablet during meals.

General guidelines

1. Ensure a good intake of protein foods at each meal.
2. Avoid too many fatty foods and try to use fats of vegetable origin. Be careful with too many sugary foods if you are watching your weight.
3. Avoid adding salt to foods.
4. Follow your 'fluid restriction' carefully.
5. Take care with your potassium and phosphate intake if you are told your levels are raised.
6. Weigh yourself regularly (watch out for both fluid weight gain and excess body weight gain).

Further information and advice

A renal dietitian will be available at your clinic appointments. If you have any queries regarding your diet, please call the renal dietitian on 01223 216655.