Kidney, bladder and urine conditions leaflets

What is potassium?

Potassium is a mineral found naturally in many foods. The amount of potassium in your diet will vary daily, depending on your food choices.

Why is the amount of potassium in my blood too high?

The kidneys normally control the level of potassium in your blood, but in kidney failure, this control is lost.

How much potassium should I have in my blood?

The amount of potassium in your blood should be between 3.5 mmol/L to 5.3 mmol/L. You may be advised to follow a low potassium diet when blood tests show the amount of potassium in your blood to be 5.5 mmol/L or above. If you are on haemodialysis you should aim to keep your potassium levels below 6.0 mmol/L.

• If your potassium levels are 3.5 – 5.3 mmol/L you are in the ‘safe zone’.
• If your potassium levels are 5.3 – 6.0 mmol/L you are in the ‘caution zone’.
• If your potassium levels are higher than 6.0 mmol/L you are in the ‘danger zone’.

Why do I need to worry, if my potassium level is high?

Too much potassium can be dangerous as it affects the rhythm of your heart and can cause sudden death.

How can I control my potassium levels?

You can:

• follow a low potassium diet
• maintain regular bowel habits (treat constipation)
• if you are on haemodialysis, do not miss sessions or dialyse for less time than advised.

Potassium is water soluble. When a food has been soaked or boiled in water, the potassium can leach out into the water it has been soaked or boiled in. Therefore, soaked potatoes are lower in potassium than jacket potatoes, and tinned mushrooms are lower in potassium than raw mushrooms.  Boiled carrots are lower in potassium than raw carrots.

Cooking methods

How you prepare and cook vegetables and potatoes will affect their potassium content. The guidance provided here should be followed to reduce the amount of potassium in your diet:

• Always boil vegetables and potatoes in plenty of water and ensure they are well cooked. Discard the cooking water used. Do not use the water to make soups, gravy, sauces or stock.
• Potatoes should be peeled and soaked for several hours (at least four hours) before cooking. Discard the water that they were soaked in and then boil as normal.
• When little or no water is used to cook potatoes or vegetables, most of the potassium stays in the food.  Therefore you should avoid using a microwave, steamer or pressure cooker for cooking potatoes and vegetables.  Avoid stir-frying, roasting or steaming (unless vegetables or potatoes have been par-boiled first).
• Boil potatoes and vegetables before frying or roasting or adding to casseroles and curries.
• Always boil vegetables before adding to stir-fries.
• Raw vegetables are generally higher in potassium.

• Follow a ‘no added salt’ diet and limit your intake of high salt foods such as tinned foods, bottled foods, packet sauces, processed meats etc. Avoid salt alternatives such as Lo-Salt, as these contain potassium.
• Have no more than one serving of potato OR starchy vegetable such as cassava, yam, sweet potato or plantain per day. A serving size is 150g (5oz) or three egg-size potatoes. Rice and pasta are much lower potassium alternatives and can be included freely as part of your diet.
• Enjoy a tomato-based pasta dish such as spaghetti bolognese if you are NOT having any potato OR other starchy vegetable. No additional tomatoes should be eaten the same day. 200g (7oz) tinned tomatoes or one serving of a ready-made sauce is equivalent to your daily potato allowance.
• Avoid having tomato soups and using sundried tomatoes or tomato purée in dishes.
• For vegetarian or vegan meals have a portion of beans, lentils, chickpeas or kidney beans in place of meat or fish with your meal. Don’t eat pulses, beans or lentils with potatoes on the same day.
• Avoid potato-based snacks such as potato crisps, tinned potatoes, instant mash and frozen potato products. These will all be high in potassium.
• If a fruit or vegetable has been tinned, then always drain the fluid it has been tinned in.
• If eating out, try to avoid potato-based dishes and chips.  Choose rice or pasta-based dishes which are lower in potassium.
• Avoid all dried fruit and foods containing them, such as fruit loaf or fruit cake.

Potatoes are a rich source of potassium. For this reason, we recommend that all potatoes should be peeled and soaked for several hours before cooking. You should discard the water that they were soaked in and then boil as normal in fresh water. If potatoes are not prepared in this way, then you could be having more potassium than needed and this could lead to high blood potassium levels.

Potatoes

Low potassium (best choice)

• Boiled potato
• Boiled starchy vegetables
• Boiled and then roasted or fried potato
• Boiled and then roasted or fried starchy vegetables
• Mashed potato (not instant or frozen) 150 g (5 oz) serving of potato (or 3 egg-size potatoes) daily
  Ensure all potato, cassava, sweet potatoes, yams, taro are boiled

High potassium (avoid)

• Baked (jacket) potato / sweet potato
• Frozen oven chips / retail chips or microwave chips
• Frozen roast potatoes
• Steamed potato / sweet potato / cassava / yam
• Instant mashed potato
• Manufactured potato products such as:
  – hash browns
  – potato waffles
  – potato wedges
  – frozen mash

Breakfast cereals

Low potassium (best choice)

Cereals that are free from bran, dried fruit, nuts and chocolates such as:

• Weetabix®
• Shredded wheat®
• Shreddies®
• porridge (not instant or in sachets)
• cornflakes
• Special K®
• Rice Krispies®
• Frosties®
• Cheerios®

High potassium (avoid)

Cereals containing bran, dried fruit, nuts or chocolate such as:

• muesli
• All Bran®
• sultana bran
• Fruit and fibre®
• chocolate-coated cereal
• instant porridge such as Ready brek®

Breads

Low potassium (best choice)

• White bread and rolls
• Granary (no seeds – limit to 2 slices a day or 2 small rolls)
• Wholemeal (limit to 2 slices a day or 2 small rolls)
• Pitta bread
• Tortilla wraps
• Bagels
• Crumpets
• French bread
• Croissants
• English muffins

High potassium (avoid)

• Fruit breads and malt loaf
• Breads containing nuts and seeds
• Naan bread – limit to ½ naan (80g) per day

Other starchy foods

Low potassium (best choice)

• Pasta
• Rice
• Noodles
• Couscous
• Yorkshire puddings
• Pastry
• Dumplings

High potassium (avoid)

• Quinoa

Fruit and vegetables should be included as part of a healthy diet as they provide us with a wide variety of vitamins, minerals and fibre. However, many are also rich sources of potassium. It is therefore important to choose the lower potassium options.

Important points

• Discard all juice from tinned or canned fruits and vegetables.
• Drain and rinse tinned vegetables before cooking.
• Avoid all fresh or pure fruit juices.
• Star fruit may cause dangerous side effects in those with kidney problems, so it is recommended that you avoid this.
• You may be advised to not have grapefruit if you are taking certain medications such as statins.

Fruit

It is important to eat no more than two portions of fruit containing low to medium levels of potassium per day. A portion of fruit is 80g (3oz).

Low potassium (best choice)

• Apple (1 small)
• Blueberries (1 small cup)
• Cherries (80g tinned)
• Clementines (2 small)
• Cranberries (1 small cup)
• Fruit cocktail (80g tinned)
• Fruit pie filling (80g)
• Gooseberries (3 stewed)
• Grapefruit (¹⁄₃ small)
• Guava (80g tinned)
• Lemon (1 small)
• Lime (1 small)
• Loganberries (80g tinned)
• Lychees (6 small)
• Mandarins (80 g tinned)
• Mango (80g tinned)
• Mixed peel (80g)
• Nectarine (1)
• Orange (½)
• Papaya (80g tinned)
• Passion fruit (pulp of 3 fruits)
• Peach (1 small)
• Pear (½ medium or 1 small)
• Pineapple (tinned) (2 rings / 6 chunks)
• Plums (80g tinned)
• Pomelo (80g)
• Raspberries (80g tinned)
• Rhubarb (80g tinned)
• Satsuma (1 medium / 2 small)
• Strawberries (80g tinned)
• Tangerine (1 medium / 2 small)

Moderate potassium (good choice)

• Apricots (80g tinned)
• Blackberries (15)
• Blackcurrants (80g tinned)
• Cherries (4 fresh)
• Figs (fresh)(1½)
• Kumquats (80g)
• Mango (2 slices)
• Melon (½ slice)
• Papaya (½ slice)
• Peaches (80g tinned)
• Pineapples (fresh) (1 large slice)
• Plums (80g stewed)
• Pomegranate (¼)
• Quince (80g)
• Raspberries (15)
• Strawberries (6)

High potassium (best avoid)

• Apricots (fresh)
• Blackcurrants (stewed)
• Damsons
• Gooseberries (raw)
• Grapes
• Greengages
• Guavas
• Kiwis
• Loganberries
• Physalis (cape gooseberries)
• Plums
• Prunes (tinned)
• Redcurrants
• Rhubarb
• Sharon fruit
• White currants

Very high potassium (avoid)

• Apricots (dried)
• Avocados
• Bananas
• Blackcurrants (raw)
• Coconuts
• Currants (dried)
• Dates
• Dried fruit mix
• Figs (dried)
• Prunes (dried)
• Raisins
• Sultanas

Vegetables

It is important to eat no more than two to three portions of vegetables containing low to medium levels of potassium per day. A portion of vegetables is 80g (3oz). This is equivalent to two heaped tablespoons.

Low potassium (best choice)

• Beansprouts (4 tbsp raw)
• Cabbage (2 tbsp boiled)
• Carrots (2 medium boiled)
• Cauliflower (8 florets boiled)
• Chickpeas (80g tinned)
• Corn on the cob (½ boiled)
• Cucumber (a 2 inch piece)
• Gherkins (80g pickled)
• Green or French beans (80g tinned)
• Leeks (½ boiled)
• Marrow (80g boiled)
• Mixed vegetables (80g frozen)
• Mushrooms (80g tinned)
• Mustard and cress (2 punnets raw)
• Olives (8 tinned / jar)
• Onions (4 medium boiled or pickled)
• Sugar snap peas (18 raw, boiled or stir-fried)
• Peas (2 tbsp frozen or tinned)
• Pepper (½ red or green raw)
• Pumpkin (80 g boiled)
• Runner beans (3 tbsp boiled)
• Squash – spaghetti type (80g boiled)
• Swede (80g boiled)
• Water chestnuts (80g canned)

Moderate potassium (good choice)

• Asparagus (4 spears, boiled)
• Aubergine (¼ fried)
• Beetroot (3 baby whole or 7 slices pickled in vinegar)
• Broad beans (80g fresh, tinned or boiled)
• Broccoli (2 spears boiled)
• Carrots (80g raw)
• Celery (2 – 3 sticks boiled)
• Chicory (80g raw)
• Coleslaw (2 tbsp raw)
• Courgette (1 medium boiled)
• Curly kale (3 tbsp boiled)
• Green / French beans (3 tablespoons)
• Kohlrabi (80g boiled)
• Lentils red (2 tbsp boiled)
• Lettuce (16 small leaves raw)
• Mange tout (18 boiled, raw or fried)
• Mixed vegetables (80g tinned)
• Mooli (80g raw)
• Onion (1 medium raw)
• Peas (mushy) (80g)
• Pepper (½ yellow raw)
• Potato salad (½ pot)
• Radish (10 raw)
• Salsify (80g boiled)
• Shallots (3 small raw)
• Spinach (80g boiled)
• Spring greens (3 tbsp boiled)
• Squash (all summer types, 80g boiled)
• Sweetcorn (baby, tinned or frozen 5 teaspoons)
• Tomato (80g tinned)
• Turnip (²⁄₃ boiled)
• Watercress (raw) (1 small cereal / dessert bowl)

High potassium (best avoid)

• Artichoke (boiled)
• Baked beans
• Blackeye beans (boiled)
• Brussels sprouts (boiled)
• Butter beans (tinned)
• Butternut squash (baked)
• Cabbage (raw)
• Celeriac (boiled)
• Celery (raw)
• Chickpeas (dried)
• Chilli beans (tinned)
• Courgette (raw)
• Fennel (boiled)
• Kidney beans (tinned)
• Lentils green / brown (boiled)
• Mung beans (boiled)
• Mushrooms (raw or fried)
• Okra (boiled)
• Parsnips (boiled)
• Radicchio (raw)
• Split peas
• Spinach (frozen then boiled)
• Spring onions (raw)
• Tomato (raw)

Very high potassium (avoid)

• Aduki beans
• Artichokes
• Bamboo shoots (tinned)
• Beetroot (fresh)
• Swiss chard
• Endives
• Mushrooms (dried)
• Pak choi
• Pinto beans
• Soya beans
• Spinach (raw)
• Sundried tomatoes
• Tomato purée

Low potassium (best choice)

• Chickpeas (tinned)
• Hummus
• Meat and poultry – all types
• Fish and seafood – all types
• Eggs
• Quorn®
• Tofu

High potassium (avoid)

• Aduki beans
• Baked beans
• Black gram beans
• Blackeye beans
• Butter beans
• Lentils (brown, green)
• Mung beans
• Red kidney beans
• Soya beans
• Nuts
• Seeds

If you are vegetarian or vegan please let your renal dietitian know. For vegan or vegetarian meals, restrict pulses and beans to the number of portions per day recommended by the dietitian. Don’t serve beans or pulses with potatoes on the same day.

All animal milks such as cow’s milk are very good sources of potassium. Therefore, milk should be limited to 300 ml (½ pint) per day.

Dairy and dairy substitutes to limit or avoid

Included in 300 ml milk restriction

• Cows milk (skimmed, semi skimmed and full fat)
• Soya milk
• Yoghurt
• Ice cream
• Custard
• Milk puddings

To avoid (these are very high in potassium)

• Almond milk
• Condensed milk
• Evaporated milk
• Milk powder
• Yoghurts containing dried fruit, nuts or seeds
• Chocolate flavoured milk-based products

Low in potassium and NOT included in the 300 ml restriction

• Oat milk
• Rice milk
• Cheese
• Crème fraîche
• Double cream

Tips

• As rice and oat milks are not included in your milk allowance, try using these for cereals and/ or hot beverages which will free your milk allowance for other milk-based foods throughout the day.
• Half water and half double cream can be used as a milk substitute. This can be used to make porridge.

Savoury snacks

Please be aware that savoury snacks can be high in salt.  Having a diet high in salt can affect your blood pressure and increase thirst, which can make it difficult to stay within your fluid allowance, if on one.

Low potassium (best choice)

• Bread sticks
• Crackers – cream, water, wholemeal
• Croissants
• Crumpets
• Dumplings
• English muffins
• Maize or corn-based snacks, eg Skips®, Wotsits®, Monster Munch®, tortilla crisps
• Pancakes
• Popcorn
• Prawn crackers
• Pretzels
• Rice-based snacks, eg Snack-a-Jacks®, rice cakes
• Wheat-based snacks eg Sunbites®

High potassium (avoid)

• Potato-based crisps
• Vegetable crisps
• Nuts and seeds
• Dried fruit
• Bombay mix
• Twiglets®
• Oatcakes
• Poppadoms
• Rye crispbreads
• Crispbreads containing seeds

Biscuits and cakes

If you are diabetic, try to limit your intake of very sugary foods.

Low potassium (best choice)

• Plain biscuits, eg Rich Tea, digestives shortbread, iced biscuits, cream / jam filled biscuits
• Ginger biscuits
• Crackers
• Water biscuits
• Wafers
• Sponge cake
• Fancy iced cakes
• Battenburg
• Angel cake
• Madeira
• Swiss roll
• Jam tarts
• Doughnuts

High potassium (avoid)

• All cakes, biscuits or cereal bars that contain seeds, dried fruit, nuts or chocolate
• Garibaldi biscuits and fig rolls
• Eccles cakes
• Malt loaf and fruit breads
• Coconut biscuits
• Ginger cake
• Jamaican cake
• Chocolate chip biscuits or cookies
• Chocolate digestives
• Fruit cake (any type, including Christmas cake)
• Mince pies
• Stollen cake
• Teacakes and hot-cross buns
• Coffee cake

Sweets and puddings

If you are diabetic, try to limit your intake of very sugary foods.

Low potassium (best choice)

• Boiled sweets
• Jelly sweets / chewy sweets
• Fruit pastilles / gums
• Marshmallows
• Boiled mint sweets
• Turkish delight
• Candied popcorn
• Lemon meringue
• Jam / treacle pudding
• Fruit pie / crumble (using low potassium fruit)
• Pavlova (using fruit from your allowance)
• Cheesecake (using fruit from your allowance, if topped with fruit)
• Pancakes

High potassium (avoid)

• Confectionery containing fruit or nuts
• Chocolate
• Toffee
• Fudge
• Liquorice
• Chocolate sponge, brownie or cheesecake
• Crystallised ginger
• Ginger pudding
• All puddings containing dried fruit, nuts or chocolate, such as Christmas pudding
• Bread and butter pudding
• Chocolate mousse
• Chocolate ice cream

If you have been advised to limit your fluid intake, ensure that you count all the fluid consumed as part of your daily fluid allowance. Please ask your dietitian if you are unsure what your fluid allowance is. You should avoid alcohol if you have been advised to do so by your doctor.

If you are diabetic, try to limit your intake of drinks and beverages containing sugar.

Drinks

Low potassium (best choice)

• Barley water
• Camp or barley cup coffee
• Cordials, squash
• Fizzy drinks eg lemonade
• Flavoured water
• Soda water
• Tonic water
• Tea – all types
• Water

High potassium (avoid)

• Fruit juices
• High juice squashes
• Fruit smoothies
• Vegetable juices
• Instant coffee
• Filter coffee (one a day)
• Drinking chocolate, cocoa
• Malted drinks (Ovaltine®, Horlicks®)
• Ribena® – all varieties

Alcoholic beverages

Low potassium (best choice)

• Spirits, eg vodka, rum, gin, whiskey

High potassium (avoid)

• Beer, lager, stout, cider
• Guinness®
• Wine
• Sherry
• Vermouth
• Port

Low potassium (best choice)

• Chilli sauce
• Herbs
• Spices
• Garlic
• Pepper (white and black)
• Vinegar
• Mustard
• Pickle
• Mayonnaise / salad cream
• Horseradish sauce
• Mint sauce
• Apple sauce
• Gravy granules
• Curry powder
• Golden syrup, sugar or honey
• Lemon curd, jam or marmalade

High potassium (avoid)

• Salt substitutes eg LoSalt®, So Lo®
• Marmite® / Bovril® / Vegemite®
• Tomato puree
• Tomato ketchup
• Soups
• Worcestershire sauce®
• Brown sauce
• Black treacle
• Peanut butter
• Chocolate spread