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Prevention of kidney stones – continued


This week I am again looking at the prevention of stones. A few weeks ago, I emphasized the need to drink fluids, in the tropics. I said not just water, but fluids meaning water containing something else, like a small amount of salt, lemon, and lemonade or fruit juices. I said this drink should be alternated with water for those who like to drink water only. I tend to find people who drink water only and sometimes excessively (for a period of time) and those who hardly drink at all. Both extremes are bad, as the body needs a constant supply of fluids to keep itself clean. The ideal is a sensible amount of fluids, so you have to empty the bladder at least four times in the day and at least once at nights. That translates into six to eight glasses of fluids per day, but this depends on one’s activity level.{{more}}

Now, we deal with the issue of diet and stones. Most people who have been diagnosed as having kidney stones ask about a diet and some are given advice to avoid certain things like calcium rich foods. In truth, although about 70 per cent of all stones contain calcium, most calcium stones are not pure. They are mixed with oxalate, phosphate, uric acid and other chemicals. So, it’s folly to assume calcium alone is the culprit. More than 50 per cent of recurrent stone formers can reduce their stone reformation rates by just increasing fluid intake. The remainder can reduce their rates by altering diet, not just calcium. Before reducing calcium in the diet we must prove that dietary calcium is the cause of the stones.
This means several blood tests and urine tests, both when the person has fasted and when they are calcium loaded. These tests are usually not done and the patient is then given a diet low in calcium, which, in some persons, may lead to weak bones and in others may actually make the problem worse. Let me explain: calcium stones are due to excess calcium in the urine. Excess calcium may arise from excessive intake (in which case diet will help) or excessive production in the blood from the bones (restricting calcium will make the situation worse!) or because there are certain tumours of the body that produces chemicals which cause the calcium to be high in the blood then in the urine (in which case restricting diet will not help). So, before going on a low calcium diet, start with a high fluid intake, and then leave the rest to the experts. Don’t assume calcium reduction will automatically reduce your stone recurrence.

In the tropics, the single most important thing to do is to increase fluid intake. Studies done have shown that reducing calcium intakes actually may increase your risk of forming calcium stones and weak bones, as the body will actually take the calcium from the bones and make the stones. The best thing to do is to reduce oxalate intake and reduce uric acid production (the two most common chemicals combined with calcium to form stones). The next thing to do is to have your calcium intake assessed; if the dietitian thinks that your calcium intake is excessive, then she may reduce it to normal, but not to less than normal.

The main sources of uric acid are foods high in proteins and alcohol, especially red wines. Oxalate rich foods include coffee, teas, nuts and oats, grapes, tangerines, spinach, green leafy vegetables, pumpkin, sweet potatoes, yams, popcorn, to name a few. That’s why the main thing is to increase fluid intake and leave the rest to a urologist or an internist who specializes in kidney diseases or metabolic disorders. Most of the persons on these restrictive diets still form stones, as do most of them using so-called “herbal” treatments to get rid of stones. Kidney stone reduction, like most of medicine, is based on science and is therefore rational. The first thing to do is to either analyze a passed stone or find a cause of the stone before changing your diet. Before that, the simplest thing to do is to increase the fluid intake!!!

For comments or question contact:

Dr Rohan Deshong

Tel: (784) 456-2785