You may not be able to sell your kidney stone for $15,000, like Gene Simmons of Kiss did on eBay! But, if you're diagnosed with these painful pebbles, you'll join the ranks of millions of other kidneystoners, including Billy Joel and William Shatner. (Overweight white males are most at risk.) Incidents have increased by 70 percent in the past 20 years, and doctors are now seeing this once middle-age complaint in ever-more children! Fortunately, you can do a lot to avoid the stones.

First, a short course: Kidney stones are hard clumps of crystals, usually made up of calcium and oxalic acid or phosphate. Sometimes they're triggered by a urinary tract infection (then they're called struvite stones), or by uric acid (which also causes gout). They can range in size from a grain of sand to a golf ball; most can be excreted through your urine — except for the Titleist!

How can you prevent a kidney stone crisis?

• Drink up to 3 quarts of water a day! Beverages such as sports drinks, grapefruit or cranberry juice and even iced tea can make it worse!
• Reduce salt; it's loaded into fast and processed foods. Opt for fresh cooked foods, seasoned with herbs and spices.
• If you have calcium oxalate stones, eating low-fat dairy is GOOD. Calcium binds to the oxalate, keeping it out of your urine.
• If you're in the kidney stone zone, avoid high-oxalate, stone-promoting foods such as red meat, spinach, beets, wheat germ, chocolate, and peanuts, and limit vitamin C supplements to 500 milligrams a day.

© 2012 Michael Roizen, M.D. and Mehmet Oz, M.D.
Distributed by King Features Syndicate, Inc.