Dietary advice for Kidney stones
It is the volume of fluid drunk that is important and water is probably the cheapest and safest. The aim is to drink sufficient fluid to ensure that your urine is dilute and therefore less likely to allow crystallization of a stone. Whether your local mains water is hard or soft does not influence your risk of further stones. Clearly it is difficult to determine how much fluid one should drink to meet the required urine output. A useful rule of thumb is the colour of the urine.
You should aim for a very light coloured or nearly clear urine (champagne colour) at all times throughout the day and any darkening (toward the colour of Lucozade) means you need to drink more fluid. Be particularly careful in situations where you may become dehydrated i.e. hot weather, long flights, air-conditioned rooms, stuffy offices, factories etc.
Mineral water is no more effective than mains water in terms of avoiding future stones; your choice is merely a matter of preference. It is also perfectly acceptable to add fruit squash or cordial to tap water to make it more palatable.
Beer and wine
Drinking alcohol in excess should be avoided. However, you may be pleased to know that the intake of small volumes of beer and wine may actually help to decrease further episodes! It is a good habit to drink water at the same time to counteract the dehydrating effect of alcohol.
Coffee (decaffeinated or caffeinated) and tea
Moderate consumption of tea and coffee is not associated with an increase risk of stone formation. However, black tea has a high concentration of oxalate and is to be avoided if possible.
These are encouraged as part of a healthy diet. However, excessive intake may be associated with an increased chance of stone formation.
Most kidney stones contain calcium but this does not mean you should stop eating dairy products. There is no evidence that eating dairy products increases the likelihood of stone formation. In fact, it is recommended that a good amount of calcium should be consumed as cutting out dairy produce may increase the risk of further stones forming. However, attempts to improve calcium intake by taking calcium tablets should be avoided.
Are there any foods I should avoid?
Oxalate is found in most kidney stones; therefore, overindulgence in foods that are rich in this substance should be avoided. There is, however, no evidence to suggest that cutting out these foods altogether is in any way beneficial.
Foods with high oxalate content include:
- Okra (Lady's Fingers or Bhindi)
- Black tea
The two most important messages in the avoidance of stone formation are moderation in diet and the need to drink good volumes of fluid each and every day, especially in hot weather.
Here are some useful summarising tips: • Drink sufficient fluid to keep the urine dilute (more than 2 litres per day)
- Avoid excessive intake of foods containing oxalate
- Eat no more than 5-7 servings of meat per week (never 2 in one day)
- Avoid a low calcium diet and consume calcium containing foods such as dairy produce with meals
- Lower your salt intake (i.e. avoid adding extra salt to food)
- Increase your consumption of vegetables, vegetable fibre and fruit