Tag: Kidney Stone Diet

About 1 in 10 people suffer from a kidney stone over the course of a lifetime.  Current evidence is suggesting that this percentage is on the rise!

If you suffer from kidney stones, you may need to follow a certain Kidney Stone Diet plan.  You would need to have some blood and urine tests to find out what kind of risk factors you may have. Based on the results, your diet changes and you may need medical treatment to prevent having kidney stones come back.  

Fluid intake

Increasing fluid intake is the essential to prevent stone formation. It reduces your risk of stone formation by almost one third!. Not drinking enough can cause your urine to become concentrated, making stones more likely to form.

Ideally you should drink at least two (preferably three) litres of fluid, mostly water, each day. You should aim to keep your urine colourless throughout the day. This should give you a urine output of at least two litres (four pints) per day.

 If certain rare stones, you will need to drink enough to produce more than four litres of urine each day, but thankfully these are not common.

You can drink tea, coffee & alcohol in moderation, but most of your fluid intake should be water or squash. We recommend that you drink one or two glasses of water before going to bed, and on getting up in the morning.

Tips to help you increase your fluid intake are:

• A large glass of water in the morning 
• keep a bottle or jug of water by your side all day; you can flavour it with fruit squash;
• try to drink one glass of water every hour;
• add slices of lemon, lime or orange to cold water; this gives it apleasant flavour and helps to make your urine less acidic;
• eat more fruit & vegetables because they contain a lot of water;and
• include moist / liquid foods in your diet (e.g. soup, stew & jelly).

Food and stone formation?

What you eat does play a part in stone formation.

It is essential to have a well-balanced diet, avoiding too many calories. This should include fresh fruit, salad and vegetables, low-fat dairy produce, and whole grain products such as bread or cereals.

A high fibre intake is helpful, although you should not eat wheat bran because of its high oxalate content.

Is calcium in my diet bad for stones?

Interestingly, reducing the amount of calcium in your diet can increase the risk of stone formation, by raising oxalate levels in your urine. A daily intake of up to 1000 mg per day is safe for calcium stone formers.

Most dietary calcium is found in dairy products (milk, yoghurt, cream and cheese). A normal, varied diet will give you about 500 mg of calcium each day. The approximate calcium contents of dairy produce are:

• milk and yoghurt – 120 mg per 100 g
• soft cheese – 400 mg per 100 g
• hard cheeses – up to 1000 mg per 100 g

If you have too much calcium in your urine, you may benefit from restricting your calcium intake, but you should discuss this with your urologist, specialist nurse or GP.

Does oxalate intake play a part in stone formation?

Yes. You should try to avoid oxalate-rich foods to keep the oxalate levels in your urine at a normal level. You should avoid eating rhubarb, celery, spinach, beetroot and sesame seeds, all of which have a very high oxalate content.

Black tea, chocolate, nuts (including peanut butter), cocoa and carob are all moderately high in oxalate. You should take them in moderation but you do not need to exclude them completely. See below for further information.

Should I restrict my salt intake?

Yes. A high salt intake can increase calcium stone formation. Do not add salt to your food at the table: use pepper, herbs, spices or vinegar as alternative flavourings. You can, however, add a small amount of salt to your food during cooking.

You should limit your intake to between 2300 and 3000 mg/day (approximately one teaspoonful of salt).

Try to eat foods with a low salt content. Avoid tinned, packet or processed foods (e.g. soups, salted crisps or nuts, tinned meats, meat paste, smoked fish and fish paste), all of which have a high salt content.

Is there anything else I can do to help myself?

It is important to reduce your weight if you are overweight. Increased physical activity should be part of any weight-reducing programme. Remember to drink plenty of fluid and avoid getting dehydrated if you sweat a lot during exercise.

Are there any other tests you can do to find out why I have made stones?

Yes. All patients who have had a kidney stone should have blood tests to check their kidney function, and make sure that their uric acid and calcium levels are not raised.

In high-risk stone formers (young patients and those who have had repeated stones), two 24-hour urine samples should be collected to 

measure the level of several chemicals in your urine. Your urologist, specialist nurse or GP can tell you more about this.

Is there anything I can do to prevent certain types of stone?

Calcium oxalate stones (pictured)
Only 10 – 15% of oxalate in your urine comes from Kidney Stone Diet intake. It is not, therefore, necessary to eliminate oxalate-containing foods completely from your diet. You should, however, aim for a moderate (and sensible) intake of oxalates.

Foods which are especially high in oxalates should be consumed sparingly. The following foods are known have a high oxalate content:

• tea & coffee (more than two to three cups per day)
• nuts (e.g. almonds), sesame seeds & nut products (e.g. peanut butter)
• cocoa & chocolate
• some fruit (figs, tangerines,plums, berries & currants)
• rhubarb
• soy products (tofu, soy milk, soycheese & soy ice cream)
• some vegetables (celery, spinach,leeks, okra, parsley & beetroot)Uric acid stonesYou should try to limit your dietary intake of purines. These are naturally- occurring chemicals, found in most foods, which are broken down by the body into uric acid.The main dietary sources of purines are:

• meat – all meats, including liver, heart, kidney, sweetbreads & meat extracts (e.g. Oxo)
• fish – especially anchovies, crab, fish roe, herring, mackerel, sardines, shrimps & whitebait
• others – yeast extracts (e.g. Bovril), beer, asparagus, cauliflower, mushrooms, peas, beans & spinach.Uric acid levels are often higher in people who are overweight, so losing weight can help you. Taking the drug allopurinol, which lowers uric acid levels in the blood, has not been shown to help in reducing the risk of uric acid stones.Calcium phosphate stonesDietary changes have little effect on the formation of calcium phosphate stones. All the general advice above is valid but you should avoid taking anything to alkalinise your urine.Cranberry juice may be beneficial because it acidifies your urine and lowers urine oxalate levels slightly.Struvite (“triple phosphate”) stonesThese are seen mostly in women after the menopause, and are usually due to infection in your urine. The bacteria involved (Proteus species) produce an enzyme (urease) which splits urea in your urine to form ammonia. This makes the urine highly alkaline, encouraging the formation of calcium,magnesium, ammonium (“triple”) phosphate stones. Once these stones form, they encourage further infection, resulting in a “vicious circle” ofrapid stone growth.A high fluid intake, low-dose antibiotics (as necessary) and acidification of the urine are all effective, but the main aim is to get rid of all your stones, which eliminates the potential for recurrent urinary infections.Drugs (urease inhibitors) are available that block the enzyme produced by the bacteria, but they are not normally used because of the high-risk of major side-effects.Cystine stones (cystinuria)Simple, basic measures remain the most important way of preventing cystine stone formation:
  • increase your fluid intake – you must drink enough fluid to produce two or three litres of urine per day; this usually means you need to get up at night to drink water
  • modify your diet – reduce your intake of methionine (from which cystine is formed) by cutting your animal protein intake
  • alkalinise your urine – this
    encourages cystine to dissolve in your
    urine. We normally do this using
    potassium citrate; this tastes
    unpleasant, and some patients can
    only tolerate it by flavouring it with fruit juice
  monitor your urine acidity (pH) – using special pH dipsticks, to be sure that your urine stays alkaline. Your urologist or specialist nurse can supply you with theseDrugs are available for the treatment of cystine stones, but are only used in patients with:
  • very rapid & frequent stone formation;
  • a frequent need for surgical intervention; or
  • poor compliance with, or a poor response to, the measures above.Drug treatment must be very closely monitored for side-effects; the agents used include:
  • tiopronin (-mercaptopropionylglycine, ThiolaTM or AcadioneTM) – this is not licensed in the UK but it is available under special agreement. It binds to cystine molecules forming a more soluble compound which is easily excreted in the urine
  • d-penicillamine (DistamineTM) – the same mode of action as tiopronin but with a higher risk of side-effects
  • captopril (CapotenTM) – normally used to treat high blood pressure but relatively ineffective, and only used if the drugs above are unsuitable.What sources have we used to prepare this leaflet?This leaflet uses information from consensus panels and other evidence- based sources including:
  • https://www.kidney.org/atoz/content/dietthe British Association of Urological Surgeonsthe Department of Health (England);
  • the Cochrane Collaboration; and
  • the National Institute for Health and Care Excellence (NICE).