Overview
Diet and chronic kidney disease
Important
This information is produced for adults under the care of Guy’s and St Thomas’ hospitals. We usually give you the information after an assessment or appointment. Your dietitian or other health professional may give you different guidance, depending on your specific medical needs.
It is important to check with a health professional before making any changes to your diet. Please contact your dietitian if you have any questions or concerns.
If you are not a patient at Guy’s and St Thomas’ hospitals, please contact a GP or specialist health professional.
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:
| Low | Medium | High | |
|---|---|---|---|
| Sodium (per 100g) | Less than 0.12g | 0.12g to 0.6g |
More than 0.6g |
| Salt (per 100g) | Less than 0.3g | 0.3g to 1.5g |
More than 1.5g |
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:
Do
- use herbs or spices, such as garlic, paprika or pepper, to flavour dishes instead of salt
- avoid using different types of salts, such as garlic salt, celery salt or pink Himalayan rock salt
- reduce the use of stock cubes, stock pots, soy sauce or Maggi® sauce (a dark-coloured, vegetable protein-based sauce)
- choose no added salt or reduced salt options
- avoid salted crisps and salted nuts
- avoid processed or convenience foods, where possible
Don't
- do not add salt to your food when cooking or at the table
- do not use salt substitutes, such as LoSalt® or Solo®, as these have potassium in them
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:
Do
- Try to eat little and often. You can eat smaller amounts at mealtimes and have a snack between meals. Examples of snacks are biscuits, cheese and crackers, toast, crumpets, yoghurt or rice pudding.
- Avoid filling yourself up with bulky, low energy foods, such as soup, fruit and vegetables.
- Avoid drinks with meals, as they fill you up quickly.
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.
Resource number: 5474/VER1
Last reviewed: March 2024
Next review due: March 2027
A list of sources is available on request.
