Kidney stones are a common problem in Singapore. Up to 10% of Singaporeans will develop kidney stones in their lifetime. What is even worse is that once someone has a kidney stone, they have a 30 to 50 percent chance of having another episode. And people who have had kidney stones before can attest to this terribly painful experience. The books say the pain is as bad as childbirth but some of my female patients say it is worse than childbirth (Yes females can get this problem too but usually its slightly less common than in men). This pain usually happens when the stone drops out of the kidney and into the ureter ( the tube connecting the kidney to the bladder) and blocks the flow of urine out of the kidney. This causes pressure to build up in the kidney and hence the pain. So if you have a large kidney stone sitting in your kidney it is like having a ticking time bomb. In fact, pilots are not allowed to fly if they have significant kidney stones.
If you had a kidney stone treated and you do not want to be the 50% who will get another stone episode. There are 3 simple behaviours you can start practising to reduce your chance of getting stones.
1. Hydration: As a friend of mine once said “dilution is the solution to pollution”. In the same way when you increase your fluid intake you do not allow the stone crystals to form and any crystal particles that may have formed can be washed out of your system. In a study we did in recurrent stone formers in Singapore we found that for 70 percent of them lacked hydration. So how much is enough? Well most guidelines suggest to drink enough water to produce 2 litres of urine a day. Honestly, most of us do not measure how much urine we produce so I often tell patients to drink at least 2 litres of water a day. A 500ml reusable bottle is good to have and if you drink 4 bottles that makes 2 litres of intake. Another useful guide is your urine color. The aim is to try and keep the urine color as clear as possible.
2. Take some citrate. Citrate is found in lemons and limes. It actually stops stones from forming. You could drink lemon or lime juice but preferably not with sugar as that is not so healthy. Alternatively, I tell my patients to cut slices of lemon or lime and put in a reusable bottle to flavor their water. At the same time it adds citrate to their daily intake.
3. Reduce salt in your diet. It has been shown that excessive salt is passed out in urine. Unfortunately it also increases calcium in the urine which is a major component of kidney stones. So reducing salt in your diet can help prevent a repeat stone episode.
Apart from these 3 simple behavioural interventions, some other things to do would be to try and reduce animal protein and maintain a healthy consumption of calcium. As for advice to reduce oxalate, I only suggest that for some of my patients. Lastly, please hold off taking megadoses of vitamin C as it may trigger formation of new stones.