June 1, 2007
A University of Michigan Health Minute update on important health issues.
Stay hydrated this summer to prevent painful kidney stones, U-M doctor advises
Increase in kidney stones is common during warmer months
ANN ARBOR, MI – We’ve all heard that it is important to drink a lot of water, especially in the summer, to replenish the fluids lost due to heat and outdoor activities. If you haven’t followed that advice in the past, here’s a reason to pay attention this summer: Staying hydrated can help you prevent what many people describe as the worst pain of their lives.
That pain is caused by kidney stones, which are becoming more common in general and also are more common during the summer months. Not drinking enough fluids can lead to the development of kidney stones, and the types of exercise that are typical during the summer tend to shake loose kidney stones, causing patients to develop symptoms from the stones.
Throughout the year, but particularly in the summer, drinking enough water is the most important step people can take toward preventing the development of kidney stones, experts say.
“One of the best ways to prevent kidney stones is to stay hydrated throughout the entire 24-hour period. I recommend my patients have at least six to eight glasses of water a day, and I ask them to make sure that they spread that throughout the entire day and up until night time. This is important year-round, but especially in the summer months,” says Gary Faerber, M.D., associate professor of urology at the University of Michigan Health System.
“It is very important for people to be aware of how to prevent kidney stones because many people – about 13 percent of men and 7 percent of women – will have kidney stones sometime in their lives,” Faerber adds.
For Sharon Bidwell, who first realized she had kidney stones six years ago, the pain was second only to labor pains. She was treated with antibiotics and pain medication, and ultimately had lithotripsy performed. This is a common procedure that uses sound waves to break up the stones in the kidney.
Not wanting to ever go through that again, Bidwell, 58, has changed her diet – especially her intake of fluids.
“I have cut back extremely on cola. I would drink five or six cans a day. I’m down to one can of soda pop a day, and I have tried to increase the amount of water that I intake,” she says. “I really want to try to avoid having kidney stones again because they’re so painful and it takes so long for them to pass. It’s just not worth not trying harder.”
The kinds of dietary changes Bidwell has made are important steps toward reducing one’s risk of developing kidney stones, especially among people who previously have had kidney stones. (See list below for more prevention tips.)
Three-quarters of people in the United States who develop kidney stones have the variety that contains calcium. Other types of stones contain uric acid, are related to urinary tract infections or are cystine stones that are caused by a genetic abnormality.
Typically, stones are passed spontaneously. For the 15 percent or so that require treatment, options include pain medications; calcium-channel blocking medications; lithotripsy (which Bidwell had); a ureteroscopy, in which a small instrument is passed up through the urinary system, and a small laser is used to break up the stone; and a procedure in which a small incision is made through the back so that the stone can be broken up – a technique used for very large stones.
7 ways to reduce your risk of getting kidney stones
- Drink plenty of water. Drink water throughout the day, including at night before bed or during the nighttime hours, so that your body stays hydrated throughout each 24-hour period.
- Cut back on drinking soda and iced tea. Dark colas in particular contain oxalate, an acid that can lead to the formation of calcium oxalate kidney stones. Iced teas tend to contain oxalate as well, and Faerber recommends that his patients who have had calcium oxalate kidney stones reduce their consumption of iced tea. Other products with large amounts of oxalate include chocolate, rhubarb, strawberries, spinach and nuts.
- Exercise and lose weight. One of the main reasons for the increasing rate of kidney stones in the United States is that the population tends to be sedentary and more people are becoming overweight, Faerber notes.
- Drink lemonade. Not the powdery mix, but the real stuff. This has been shown to reduce the risk of kidney stones, Faerber says.
- Ask your physician about medications that can help prevent kidney stones. Medications include those that control the amount of acid, alkali or cystine in the urine – factors that can cause kidney stones to develop.
- Ask your physician if you should continue taking calcium supplements. Some studies have shown that foods rich in calcium may actually help to prevent kidney stones, but taking calcium in pill form may increase the risk.
- Ask your physician about foods rich in vitamin D. For people with highly acidic urine, you may need to eat less meat, fish and poultry – foods that increase the amount of acid in the urine.
For more information, visit these Web sites:
U-M Adult Health Topics A-Z: Kidney stones
U-M Adult Health Topics A-Z: Lithotripsy for kidney stones
NIH/National Kidney and Urologic Diseases Information Clearinghouse
National Kidney Foundation
Written by Katie Gazella
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