Overview

Diet is an important part of managing and treating chronic kidney disease. This is a long-term condition, where the kidneys do not work as well as they should.

If you eat a healthy, balanced diet that is low in salt, this will help to manage your:

• blood sugar levels
• cholesterol levels (a natural fatty substance in your blood)
• blood pressure

Managing these 3 things can help to slow down the progression of chronic kidney disease.

How a kidney dietitian can help you

You may be referred to a kidney (renal) dietitian for several reasons, at different stages of living with chronic kidney disease.

Kidney dietitians can give you advice about:

• ways to prevent or deal with any unintentional weight loss or malnutrition (when your diet does not contain the right amount of nutrients)
• the best foods to eat to prevent a build-up of waste products in your body, such as potassium, phosphate, urea and fluid
• how to follow a well-balanced diet that contains all the nutrients your body needs to be healthy

Your diet may change several times within months or years. This is because your dietary needs change as your condition or treatment changes.

Salt

It is important to reduce the amount of salt in your diet. Eating too much salt can raise your blood pressure. This can increase your risk of heart disease and stroke, and make your kidneys work less well.

Too much salt in your diet can make it difficult to control the fluid in your body. This can lead to symptoms including:

• puffy face and ankles (oedema)
• shortness of breath
• fluid around your heart and lungs

Reducing the amount of salt in your diet can help to prevent these symptoms.

Aim to have less than 1 teaspoon (6g) of salt each day.

Salt is sometimes labelled as sodium. Sodium is the part of salt that affects your blood pressure. You can use the following table to check if a food product is high in sodium or salt:

If a food label does not tell you how much salt or sodium it contains, check the ingredients list. The closer that salt or sodium is to the start of the ingredients list, the more salt it is likely to have.

Many products in supermarkets are labelled with traffic light colours. This shows you at a glance if the product has:

• high (red)
• medium (amber)
• low (green)

amounts of salt (and other nutrients) in 100g of the food. It is best to choose foods that are labelled green for salt whenever possible, and limit those that are labelled red.

Here are some tips to reduce the amount of salt in your diet:

Fluid

Your kidneys control the amount of fluid in your body. If the kidneys stop working properly, they cannot do this. Fluid can then build up and cause swelling and shortness of breath. In the long term, this can damage your heart.

If you are not having dialysis treatment, you should usually try to drink about 8 glasses of fluid every day. This helps to make sure that you stay well hydrated. Your doctor or nurse explains if you need to restrict how much fluid you drink.

When you start dialysis treatment, you will probably need to reduce the amount of fluid that you drink every day. This is to stop fluid building up in your body. How much you can drink depends on many different things, such as the volume of your urine (pee) each day. Your doctor or nurse explains what is best for you.

Protein

Your body needs protein to help:

• build muscle
• repair tissue
• fight infection

If you have chronic kidney disease, too much protein in your diet can cause a build-up of waste products in your blood. An example of this is a substance called urea. It is still important to include protein with your meals but not too much. Your dietitian can give you advice about this, if needed.

Foods that are high in protein include:

• meat (especially lean meat such as chicken, turkey, beef and pork)
• fish
• dairy products
• eggs
• nuts and pulses (such as beans and lentils)
• tofu
• Quorn™ (a meat substitute)
• soya products

Potassium

Potassium is a mineral found in your blood. It helps to keep your muscles, nerves and heart working properly.

Healthy kidneys maintain a normal level of potassium in your blood. When your kidneys do not work properly, the potassium in your blood can build up. This can be dangerous because it can cause an abnormal heartbeat.

If your potassium levels are high, you may be advised to follow a low potassium diet. A dietitian can give you advice about how to reduce the potassium in your diet.

Not everyone with chronic kidney disease has to follow a low potassium diet. Your doctor, nurse or dietitian explains if you need to do this.

Phosphate

Phosphate is another mineral in your blood, which healthy kidneys usually keep at a normal level. 

When your kidneys do not work properly, they may not be able to clear enough phosphate from your blood. High levels of phosphate in your blood can:

•    weaken bones
•    make calcium build up in your blood vessels

If your phosphate levels are too high, you may be advised to follow a low phosphate diet. A dietitian can give you advice about how to reduce the phosphate in your diet.

Not everyone with chronic kidney disease has to follow a low phosphate diet. Your doctor, nurse or dietitian explains if you need to do this.

You may also need to take a phosphate binder with your meals. This is a medicine that helps to reduce the level of phosphate in your blood. It may be recommended for you, in addition to a low phosphate diet.

Diabetes

If you have diabetes, it is important that you try to keep your blood sugar levels within range. Poorly controlled blood sugar levels can cause more damage to the kidneys with time.

To keep your blood sugar levels in range, it can help to:

• eat a healthy, balanced diet
• avoid too many sweet or sugary foods

Your doctor can explain how often to test your blood sugar level and confirm your target blood sugar range.

If you have a small appetite

There may be times when your appetite is poor or you cannot eat as much as usual. It is important that you do not lose too much flesh weight (fat or muscle) during this time. This can cause:

• muscle weakening
• slower healing
• slower recovery from illness

If you have a small appetite, please ask to see a kidney dietitian or contact us. You may also find these tips helpful:

SCALE renal weight loss clinic

If you are overweight or obese, this can increase your risk of getting:

• high blood pressure
• heart disease
• diabetes

If you already have one of these conditions, being overweight can make it worse. Losing weight can help to slow down the progression of chronic kidney disease.

Your body mass index (BMI) is a measure of your weight compared with your height. If you have a BMI higher than 30, you can come to our SCALE renal (kidney) weight loss clinic. SCALE stands for:

• Supported
• Change in
• Activity
• Levels and
• Eating

This is a 1-year programme held at Guy's Hospital. 

You have an appointment at the clinic every month for the first 6 months. After this, you have follow-up appointments at 9 and 12 months. At each visit, a kidney dietitian and physiotherapist give you advice and support to help you reach your weight loss goal.

If you are interested in our SCALE programme, please ask your dietitian, nurse or doctor for more information.