NUTRITION
Kidneys normally remove waste products such as phosphate, potassium, urea
and extra fluid from the body. These waste products and fluids come from the
foods that we eat and liquids we drink. When the kidneys are not working well,
they may not be able to get rid of these waste products effectively allowing
them to build up in the blood. To ensure that these levels do not rise too much
it may be necessary to follow a special diet.
There is no single renal diet, and advice will vary depending on things such as
weight, level of kidney function, blood tests and if appropriate dialysis choice,
detailed individual advice for patients is available from the renal dietitian.
Some patients will be very lucky and will not need any diet or fluid restrictions.
Other patients will need to restrict one or more of the following depending on
their blood results.
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Sodium
Fluid
Potassium
Phosphate
SODIUM
A diet high in salt can contribute to raised blood pressure, and fluid retention.
If you are on a fluid restriction, salt can make you thirsty and therefore makes
it difficult to stick to your fluid limits.
General Tips For Reducing Your Salt Intake
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Choose fresh unprocessed foods most often e.g. meat, fish, eggs, milk,
yoghurt, vegetables, fruit, rice, pasta and pulses.
Avoid adding salt at the table.
Do not use sea/rock salt or salt substitutes.
Most of the salt we eat is hidden in processed or convenience foods e.g.
ready meals, pasta sauces, so try to eat them less often and when you do,
check food labels and go for lower salt choices.
Breakfast cereals do tend to be high in salt but should not be cut out of
your diet. Check the labels to help you choose lower salt breakfast
cereals. Try puffed wheat, wheat biscuits or muesli with no added salt.
Bread is quite salty but a staple in the diet so when you’re buying bread,
compare the amount of salt in different types of bread e.g. wholegrain,
multigrain and high fibre white, and choose the lower one.
Go easy on the ketchup, soy sauce, mustard, pickles and mayonnaise –
these can be high in salt.
Some lower salt products still contain a lot of salt, so check their food
labels.
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Good snack ideas which are low in salt are fruit, plain popcorn or unsalted
nuts or seeds, instead of crisps or crackers. If having crisps choose ones
which are unsalted.
Your taste buds will gradually get used to eating less salt.
Cooking
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Try not to add salt during cooking or add only a small amount.
Use herbs, spices and black pepper to flavour your foods instead of salt.
Try marinating meat and fish in advance e.g. in lemon juice, garlic or chilli
to give them more flavour.
Roast vegetables to bring out their flavour.
Make your own sauces using ripe flavoursome tomatoes and garlic.
Homemade biscuits and cakes can be made without salt using unsalted
butter or margarine.
Eating Out
If you’re eating out you can still eat less salt by choosing the right dishes.
 At the sandwich bar, go for fillings such as chicken salad or poached
salmon, instead of ham or cheese and pickle.
 If you are having a cooked breakfast have only one salty food e.g. bacon
or sausage and accompany with fried or scrambled egg, mushrooms,
tomatoes or toast.
 If having chips always ask for them without salt.
 When having a pizza, choose vegetable or chicken toppings instead of
pepperoni, bacon or extra cheese.
Understanding Food Labels
Food labels can give the salt or sodium content of the product. Salt is sodium
chloride.
To convert sodium to salt, multiply by 2.5.
For example:
1 g sodium = 2.5 g salt.
Food high in salt contain more than 1.25g salt or 0.5 g sodium / 100g product
Foods low in salt contain less than 0.3g salt or 0.1g sodium / 100g
product
FLUIDS
Some children who have problems with their kidneys especially those on
dialysis will need a fluid restriction, this is the maximum amount of fluid that
they can have to drink each day.
If you are given a fluid restriction to follow it is important that you keep to this
amount, as excess fluid can increase your blood pressure and affect the
health of your heart.
To stick to the fluid restriction, all drinks must be measured and foods with a
high water content should also be counted and included in your fluid
allowance.
See the guide below to see how much of the food should be counted as fluid.
Weight in grams = fluid in mls
Ice lolly / ice pops
Ice cube
Milk
Jelly
Soup
Gravy
Ice cream
Cream – single only
Custard
Yoghurt
(100% is fluid)
(100% is fluid)
(100% is fluid)
(100% of the weight is fluid)
(100% of the weight is fluid)
(100% of the weight is fluid
(50% of the weight is fluid)
(50% of the amount is fluid)
(50% of the weight is fluid)
(50% of the weight is fluid)
Lots of other foods also have fluid in them but at present you do not need to
include them.
Tips to help you drink less fluid
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Measure your favourite cup to see how much it holds.
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Use a small cup or only half fill your cup.
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Salty and spicy foods can make you feel thirsty, trying to eat less salty
foods e.g. crisps, processed foods can reduce your thirst.
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Have small drinks spread through out the day, don’t drink all your fluid
allowance in one go.
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Try to reduce the amount you drink at mealtimes so you have more for
in between your meals.
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You may find it useful to measure out your days allowance into a jug in
the morning and take all your drinks from this throughout the day so
you can see how much of your allowance you have left.
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Use a straw as you tend to drink less fluid using them.
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Cold drinks are good when you are thirsty. Try adding plastic ice cubes
to drinks to cool them as normal ice cubes melt and use more fluid.
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Try sweets like mints or boiled sweets rather than having a drink.
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Try having ice pops or squash flavoured ice cubes if you are thirsty
(remember these need to be counted in your fluid allowance).
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Rapid weight gain is usually due to fluid not actual weight gain.
POTASSIUM
Potassium is a mineral which healthy kidneys remove form the blood when
there is an excess. Potassium is needed by the body for the normal
functioning of nerves and muscles, including the heart but too much
potassium is harmful to the heart so potassium levels should be kept within
the normal range. Most of the potassium in our diets comes from fruit,
vegetables and potatoes. If you need to follow a potassium restriction your
dietitian will provide you with further information.
PHOSPHATE
Phosphate is another mineral which healthy kidneys remove from the blood
when there is an excess. Phosphate is important in the diet for growth and to
form healthy strong bones, however high phosphate levels can cause
problems with your bones and heart disease.
The main sources of phosphate are dairy foods, meat, fish and meat
alternatives. Most high phosphate foods are also high in protein which is vital
for growth so they should not be avoided completely.
If you need to follow a phosphate restriction your dietitian will provide you with
further information.
If your phosphate levels are high you may need to start taking a phosphate
binder. Phosphate binders, bind phosphates and excrete it via the gut (in
your poo) Therefore decreasing absorption from the gut. The most common
type of phosphate binder is Calcium carbonate e.g. Calcium Carbonate
Suspension, Rennie, Tums, Remegel. These need to be taken prior to a meal
for them to work effectively. A starter pack is available so that you can try the
different types of binders which are available and choose the one that you
prefer.
For further information on the renal diet please contact your dietitian.
Useful website
www.kidney.org.uk/kids/diet/