Eat, Drink And Be Wary

More women seem to be getting painful kidney stones than ever before. Should you change your diet?
    DON'T HAVE A PROBLEM with my prostate, and pam-phlets on the wonders of Viagra seem beside the point. Yet, here I am in a urologist's waiting room. As I sift through men's magazines for something to read, the other patients all men over the age of 60 stareas though I've wandered into the wrong-sex rest room. Urology has always been a man's field for both doctors and patients. Serious "plumbing prob-lems" requiring a specialist's expertise are simply less com-mon among women than men.
    But that balance may be shift-ing. Kidney experts in the Unit-ed States and Europe have begun to notice a troubling trend: The number of women getting excru-ciating kidney stones seems to be on the rise.
    A decade ago, about 450,000 men in the United States and a third as many women periodical-ly suffered from stones jagged burrs of calcium and other crys-tallized minerals that scrape and terrorize as they descend from the kidney through narrow byways of the urinary tract. Today's preva-lence is closer to a million. A third of cases require hospitalization, and while men still fall victim more often, women are catching up, says stone specialist Glenn Preminger of Duke University in Durham, North Carolina.
    "Nobody's certain yet how big the shift is or what's behind it," Preminger says. "There are prob-ably at least several factors, but in my opinion one of the best places to look would be diet. Changes in the female diet."
    As a young woman who gets at least one stone every few years, I pay sharp attention to those sorts of hunches anything that might give me a leg up on pre-vention. My case is, admittedly, even more unusual than most women's: I had my first kidney stone attack at age five.

    "Attack" is an apt description: The sudden onslaught is akin to having a pickax thrust into your lower back, as muscles there contract, trying to move the snagged stone along. You can curl into a ball, jump up and down, or lie still, but nothing eases the radiating pain, which can persist off and on again for days, accompanied by fever, nausea, and blood in the urine. As a doctor once described the process to me, "Imagine a bowling ball forced down a cocktail straw."
    My parents suspected appendicitis the day I first hunkered over in pain. At the emergency room, blood and urine tests suggested kidney trouble instead. Then, as now, doctors tried to avoid surgical removal of the stone; they prescribed pain relievers until the pebble worked its way out. But squelching an attack is only half the battle. Once you've had one stone, you're likely to get more. Over the next two decades I endured another 14.
    These days, with any luck, you needn't suffer so much. While doctors can't say why one in 20 women will develop kidney stones, they have identified a few triggers to differ-ent sorts of stones among susceptible people and come upi with specific drugs that can help. The strongest predis-posing influence —a family history of the disorder triples your risk and can't be altered. But under the wrong con-ditions, anyone can form a stone. By following some key precautions, you may be able to avoid that first attac altogether, whatever your genes. Take this advice fromq a veteran:

GET PLENTY OF CALCIUM, BUT...
    There are several types of kidney stones, but more than 80 percent have calcium as the leading constituent. Mine are of the most common type: an amalgam of calcium and a salt called oxalate. Some doctors still advise patients like me to avoid dairy products, but experts say that's a bad idea. Studies published in the last two decades by Gary Curhan Harvard University School of Medicine and William Robertson at the Institute of Urology and Nephrology London have shown that a diet low in calcium actuall boosts the likelihood of stone formation, perhaps because it saps calcium from the skele-i ton and sends it into the urine2 Wcak bones and even more' stones? No thank you.
    On my doctor's advice, I now follow the minimum recommendation for all women my age and try to get 1,000 milligrams of calcium in my food daily. I don't take calcium supplements, though most experts say it's safe to do so as long as you take them with' meals and drink plenty of water. What about the juices, margarine, ice cream, and can-dies now fortified with the mineral? They can be a goodi way to get the calcium you need; just don't go overboard., In 1997, the National Academy of Sciences for the firsti time set a recommended upper limit on calcium of 2,500 mg a day for all adults, partly because the risk of kidney' stones increases when levels of the mineral are higher.

GO EASY ON THE MEAT
    Epidemiologists have long recognized that the more meat, fish, poultry, or eggs a nation consumes, the higher its incidence of kidney stones. The most dramatic evidence comes from japan: 30 years ago, when meat and fish werel considered flavorings, not entrées, kidney stones were almost unheard of. Today the Japanese eat much more the way Americans do and are nearly as likely to get stones. A few studies from England and Italy also suggest a decade-long increase in the prevalence of kidney stones, and a bump in meat con-sumption seems the likeliest explanation.
    A diet high in animal protein and low in fruits and vegetables alters kidney chemistry in several ways. First, extra calcium is drawn from bone into the blood and eventually the urine. Meat consumption also cuts the body's production of urinary citrate, a natural inhibitor of stones. Lastly, animal protein ups production of uric acid, which, when concentrated, can crystallize to form a urinary pebble.
I don't mean to exaggerate the problem. The healthy kidney is a wondrous filter, and individuals vary widely in the amount of meat they can handle. But be warned: Experts say the high protein—low carbohydrate diets currently popular almost certainly increase the risk of stones for some people, most of whom won't know they're susceptible until their first attack.
    To be safe, urologists urge carnivorous moderation for everyone: For your kid-ney's sake, restrict the meat or fish in your diet to less than six ounces daily. And since sodium increases calcium excretion, too, cut back on salt.

WATCH THE CHOCOLATE
    What do chocolate, leafy green veg-etables, okra, beets, nuts, and strawber-ries have in common? All contain high amounts of plant compounds known as oxalates that can aggravate a tendency to develop calcium oxalate stones. (Para-doxically, tea and coffee, also high in oxalates, seem to curb stone formation. Go figure.)
    The vast majority of Americans need to gobble more servings of fruit and veg-etables, not fewer. (And at least one study in Great Britain found that about a third as many vegetarians as meat eaters had stones.) Still, stone sufferers should be selective. If you've had an attack and the doctor tells you oxalates are to blame, you'll probably want to go easy on strawberries, chocolate, and the like. Also, oxalates are a by-product of vitamin C metabolism, which is why some kidney experts now urge their patients who get calcium oxalate stones to skip vitamin C supplements, or at least to take no more than 500 or 1,000 mg daily.

DON'T IGNORE INFECTIONS
   So-called struvite stones account for only labout 10 percent of all stones. But they're uch more common among women 'than men, in part because they're trig-gered by urinary tract infections. Get thee to a doctor at the first sign of a UTI; a simple prescription for antibiotics could save you days of agony.

DRINK MORE WATER
    This sounds too simple to be true: Dehydration fosters stones. Doctors through-out the world see more kidney stones in summer months. Athletes, outdoor workers, and others who perspire profusely are especially vulnerable, as are eachers, assembly line workers, and anyone else who puts off drinking water ecause they don't have time for a bathroom break. But the consequences are too great to ignore. A recent study showed that women who drank 11 glasses of liquid a day were 38 percent less likely than women who drank half that amount to develop stones.
    If, despite your best efforts, you wind up in the emergency room one day with a stone, once the crisis has passed make sure that you follow up with a sympathetic urologist to determine the cause. Five years ago, I finally found a doctor who ran the right tests and learned that I have low levels of urinary citrate, a natural inhibitor of stones (it bonds with calcium, preventing oxalates from doing so). For the rest of my life, I'll need to take a daily potassium citrate supplement, something similar to concentrated lemonade. So far, so good-no stones since.
    Still, I check in regularly with my urologist. Women with kidney stones may be at higher risk for certain urological cancers, and as we age, the frequency at which we develop stones goes up.
    Never mind the 3-D model of the male urinary system in the doctor's waiting room. Now that researchers are finally looking our way, the understanding of female urology is progressing, too. For now, I'm content to bury my nose in a copy of My Prostate Health, swallow my medicine, and bide my time.