Fact Sheets Nutrition and kidney failure and Calcium and phosphate
Helping kidneys to control body chemistry by eating a sensible diet is an important part of managing chronic kidney disease(CKD). Being careful about what is eaten can reduce the amount of fluid and waste build-up, helping to minimise symptoms and side effects of CKD.
Your dietary needs will change with the different stages of your kidney failure.
If the kidneys are not working properly, the waste builds up in the bloodstream and you may feel weak, tired, and sick. The other balancing act the kidneys perform is the regulation of the body’s fluid balance. Some people with kidney disease may retain fluid, which leads to puffiness, swollen ankles, hands and feet and breathlessness.
Other than reducing salt and fat intake, there is no standard kidney disease diet. An Accredited Practising Dietitian experienced in treating kidney disease can help plan your meals, taking into account how you are feeling, your age, lifestyle, weight, muscle size, health status and blood test results. Ask your general practitioner or kidney specialist for a referral to an Accredited Practicing Dietitian.
Contact Dietitians Association of Australia to find a local Accredited Practicing Dietitian. If you have seen a dietician, information below should not take the place of the diet prescribed for your personal health profile.
Things that are important to nutrition include getting the right amount of energy from food, as well as staying at a healthy body weight. Controlling important nutrients in the diet is also helpful. These nutrients are summarised below.
Sodium (Salt)
Kidney disease, high blood pressure and sodium are all linked. Most people should limit the amount of sodium in your diet. Even if you don’t use salt in cooking or at the table, your diet can still be high in sodium. This is because sodium is found in many processed foods. 
Generally, foods that have a lot of sodium include:
- salty seasonings like soy sauce, teriyaki sauce and garlic or onion salt
- most canned foods and some frozen foods
- processed meats like ham, bacon, sausage and cold cuts
- salted snack foods like chips and crackers
- most restaurant and take-away foods
- canned or dehydrated soups like packaged noodle soup
Salt substitutes are often high in potassium and should not be used without consulting your doctor or an Accredited Practising Dietitian.
Recommended links:
Australian World Action on Salt & Health Drop the Salt Campaign for some helpful tips
For an extensive brand list of low sodium foods go to www.lowsodiumfoods.com.au
Potassium
Potassium is an important mineral in the blood helping your muscles and heart to work properly. Healthy kidneys usually excrete any extra potassium from your body. Too much or too little potassium in the blood can can cause an irregular heartbeat. As your kidney disease progresses you may need to limit the amount of high-potassium foods you consume. Blood tests can monitor your potassium levels. Potassium is found in large amounts of fruits and vegetables such as:
- potato, sweet potato, pumpkin
- tomato, avocado, beans (i.e baked beans, soy beans) and lentils
- banana, custard apple, stone fruits such as nectarines
- dried fruit, vegetable juice, kiwi fruit and olives
- tinned and homemade soups
- liqueurs, red wine, cider, stout, nuts and seeds
- spinach, mushrooms
- dried peas, beans, baked beans
- chocolates, cocoa, liquorice
- high fibre breakfast cereals, unprocessed bran
Tip for reducing potassium intake - cut vegetables into small pieces, soak them in a large volume of water for 1-2 hours before cooking, drain and cook normally. Alternatively, boil them and drain off the water. Not all fruits and vegetables have the same amount of potassium.Talk to your renal dietician about what diet is appropriate for your individual needs.
Fluids
When diagnosed with CKD, some people need to drink large amounts of fluid while others may need to limit fluid intake. Your suggested fluid intake will depend on your urine output, fluid build-up and blood pressure. Fluids are any foods that are liquid at room temperature including ice cream, yoghurt and ice cubes. Fluid is also contained in food like cooked pasta and rice, salad ingredients, soup and watermelon.
Tips for restricting fluids - sip small amounts throughout the day, use smaller cups and glasses, remember that foods containing fluids need to be included in your fluid allowance.
Phosphate & Calcium
Phosphate and calcium are minerals found in your blood and bones. With CKD, your kidneys may not remove enough phosphate from your blood. A high blood phosphate level may cause you to itch and lose calcium from your bones which may then become weak and break easily. Avoiding large amounts of foods high in phosphate will help lower your blood phosphate level. Additionally special medications known as phosphate binders can be taken with meals to absorb the phosphate. Phosphate is found in large amounts in:
- dairy products such as milk, cheese, yoghurt and ice cream
- dried beans and peas such as kidney beans, split peas and lentils
- nuts and peanut butter
- drinks such as cocoa, beer and cola drinks
Protein
Getting the right amount of protein is important to overall health and affects how well a person feels. The body needs protein for building muscles, repairing tissue and fighting infections. You may need to follow a diet with controlled amounts of protein. This can help regulate the amount of waste in your blood and increase the life of your kidneys. Protein comes from animal or plant based products:
- animal based products include: eggs, fish, meat, chicken, cheese, milk and other dairy foods.
- plant-based products include: nuts, peanut butter, lentils, baked beans, bean soup mix, beans salad mix, chickpeas and hommus dip.
Protein builds, repairs and maintains body tissue. It also helps to fight infections and heal wounds. Urea is a waste product, which is formed when the body breaks down protein. Your eating plan should be designed to provide enough protein for your body without causing urea to overload the kidneys.
Nutrition and CKD - points to remember
- Your nutritional care plan needs to be personalised and based on your kidney function.
- Ask questions until you understand your diet.
- You may need to measure foods and fluids; for greater accuracy, measure with a cup or scale.
- Take your medication as prescribed.
- Organise reviews and follow-up with your renal dietician.
- Be aware of and note your trends in body weight, blood pressure and blood values.
- Inform your doctor or dietician if you are losing weight or have any concerns about your diet.
- Following your suggested nutritional care plan may not treat or cure your kidney problem, but it could help you reduce some of the symptoms, and improve your general feeling of wellbeing.
If confused about advice provided by your dietitian about your renal diet, call our Kidney Health Information Service on:
For quality information via external websites
Food composition, standards, guidelines - to support nutrition for all stages of CKD and post transplant
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iKidneyDiet - iTunes application Clever mobile phone app which gives levels for the 3 Ps - Potassium, Phosphorous, Protein - when watching intake for a renal diet. Some USA products are noted
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UPDATED 13 MAY 2013
Disclaimer: This information is intended as a general introduction to this topic and is not meant to substitute for your doctor's or health professional's advice. All care is taken to ensure the information is relevant and applicable to each Australian state. It should be noted Kidney Health Australia recognises each person's experience is individual and variations do occur in treatment and management due to personal circumstances. Should you require further info always consult your doctor or health professional.