The aim of this section is to answer some of the questions you may have about the role diet plays in helping to prevent kidney stones forming in people with cystinuria. If you have any further questions or concerns, please speak to a Dietitian.
How can changing my diet help?
The kidneys of people with cystinuria process an amino acid called cystine differently from other people (Note: amino acids are the building blocks of proteins in the body). This means that cystine can build up in your urinary tract causing kidney stones. The main aim of managing cystinuria is to prevent the formation of kidney stones. Making changes to your diet may help prevent the stones forming.
More information on each of these methods can be found below and in the 'Diet... tell me more' section.
By increasing your fluid intake, the concentration of cystine in the urine is reduced and stones should form less easily. You should aim to produce at 2 to 3 litres of urine per day. This means that you should drink more than 3 to 4 litres of fluid per day.
Reducing your salt intake reduces the amount of cystine in your urine. Therefore, following a ‘no added salt’ diet may help prevent stones forming. Your Dietitian will give you information on the ‘no added salt diet’.
Cystine is made in the body from methionine. Therefore, a diet low in methionine can help to reduce the amount of cystine passing through the kidneys and may help prevent stone formation.
Methionine can be reduced in the diet by decreasing your intake of animal protein foods. It is important that you get enough protein in your diet to stay healthy. A Dietitian will help you to adjust your diet to reduce the amount of methionine and ensure you receive all other nutrients you need.
The alkalinity or acidity of a substance is measured by pH. A pH of 7 is neutral. A pH less than 7 is acidic; a pH greater than 7 is alkaline.
Alkalinisation of the urine (making it more alkaline and less acidic) is important in cystinuria as it makes cystine more soluble. This means that more cystine can be dissolved in the urine and excreted from the body rather than being deposited in the kidneys to form stones. The best urine pH for people with cystinuria is 7.5.
Decreasing intake of animal protein foods decreases acid in the diet and may help to alkalinise the urine. Increasing intake of fruits and vegetables may also help alkalinise the urine.
A balanced diet that contains all the nutrients your body needs to be healthy.