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Can kidney stones be prevented?


This week I’m looking at what causes stones and how to prevent them. There are many causes of stones, but it eventually boils down to a high concentration of “chemical” in the urine. These chemicals vary by the type of stone. The most common chemical is calcium, but calcium alone cannot form a stone; it has to be combined with something else and in most cases more than one of these “other things”. So, there is very little basis for the universal limiting of calcium intake when someone has a stone. Actually, limiting calcium intake may “cause” other forms of calcium stones, as I will explain later.{{more}}

Other common chemicals forming stones include oxalate, urate or uric acid, ammonium, magnesium (which can also prevent stone formation) and phosphate, but there are so many other chemicals and causes like medications (about 20 of them!), amino acids, infections and strange substances like xanthine and cysteine. To make matters worse, none of these chemicals may be present in excessive amounts in the urine, but the patient’s diet of a high fat or animal protein intake or high salt intake or obesity or a lack of fluids (not just water) in the diet may cause stones. Finally, like water and magnesium, there are other chemicals which, if present in sufficient quantities in the urine, actually reduce the risk of stone formation. These substances include some acids or alkalis like citrate (as in citric acid from citrus fruits) or bicarbonate (from baking soda or citrus fruits!) and other urinary proteins or “inhibitors” which help to prevent stones. So, stones formation is a complex interplay of factors with stone promoting chemicals making stones versus inhibitors trying to prevent them.

Overall, the single biggest action anyone can do to prevent stones is to drink fluids (not fuel!) and liquids (not liquor!). Fluids and liquids, not water. Most people including my Seventh Day Adventist friends, like to emphasize water for its “purity” and its ability to cleanse the body, but this is a fallacy. Water maybe works in cold climates where the humidity is low, because a significant amount of water is lost from the skin and breath from evaporation via breathing and perspiration, but in the tropics, our bodies lose heat via perspiration and sweating, and the water lost also has some salt, some of the fluid you drink should have some salt. Excessive pure water replacement when salt is also lost from sweating can lead to water intoxication. Yes, too much water can poison you! So, what kinds of fluids can you drink? First water, but not only water. Everytime I see someone on a water diet, I know they are bound to fail, not only because water is not palatable unless you are thirsty or you have a obsessive compulsion to drink water, but because water causes you to urinate often. Water should be mixed with fruit juices, or if you insist on water only, add a little salt or squeeze a lemon or a lime in every other glass of water.

How much fluid should you drink in order to avoid stones? The answer is a sensible amount. That means don’t wait until you are thirsty to drink. Instead drink a certain amount every few hours and that amount depends on your body size. Most of us don’t wait until we are hungry to eat, and we eat on average three to four times a day. If we drink one full glass or cup of liquid with each meal and then one in between, then we end up with six to eight glasses or cups of fluids each day. This can be more for very active people, especially those in the sun. You should visit the bathroom to pass urine at least four times during the day from 6 a.m. to 6 p.m. and at least twice at night from 6 p.m. to 6 a.m. The above are guidelines not hard and fast rules. Next week, I will elaborate on other ways to prevent stones and look more at diet.

For comments or question contact:

Dr Rohan Deshong

Tel: (784) 456-2785