Prevention of stones

Kidney stones are increasingly common and whilst getting the right surgical treatment is important to become stone-free, it is then vitally important to ensure changes are made where needed to minimise chance of future stone episodes. Recurrence is estimated between 20-50% at 5 years after a first stone episode. A checklist of important lifestyle measures for any stone former would be:

1. Lose weight to achieve optimal body mass index (BMI). "We are what we eat". Overweight people are at significant increased risk of stone formation and causes a more acidic urine (lower pH) which tends to favour stone formation.

2. Ensure adequate fluid intake to achieve dilute urine. Evidence shows stone formers need to achieve a minimum of 2 litres urine output per day and therefore need to drink 2.5-3.0 litres per day to achieve this. If you sweat a lot, or undertake strenuous exercise, your needs may be significantly more.

3. Follow a low salt diet where possible. Salt is bad for kidney health and can promote stone formation by increasing calcium excretion in the urine.

4. Ensure a balanced diet. Limit animal protein if intake is high. Ensure plenty of fruit and vegetables. Meat will also cause a more acidic urine (low pH) favouring stone formation. Coversely fruit and vegetables raise the pH which will generally make stone formation less likely.

5. Ensure a normal calcium intake. A high intake or a low intake can paradoxically increase the risk of stones

Advice may need to be individualised and based on personal circumstances, stone analysis, frequency of stone formation.

This podcast on 'The Doctor's Kitchen' with Dr Rupy Aujila discussing kidney stones and diet with Matthew Bultitude may well be of interest.

Occasionally there may be an underlying cause to why you form kidney stones. It is important that the appropriate tests are done to check this out. Sometimes specific medications can be given such as:

1) Alkalinising agents - these make the urine less acidic. Examples are potassium citrate or sodium bicarbonate

2) Thiazide diuretics - in some patients with recurrent calcium stones or if high calcium in the urine (hypercalciuria), these type of medications may be prescribed to lower the urinary calcium. This is often done in conjunction with a nephrologist.

For rare but specific stone types, other medications may be given. An example is cystinuria where medications that bind cystine may be given. Matthew Bultitude has a special interest in this condition and runs this patient information website which contains a lot more information: www.cystinuriaUK.co.uk - although aimed at patients with cystinuria, the dietary advice maybe helpful for all stone formers.