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Doc: Diet advice for kidney stone sufferers

Keith Roach
To Your Health

Dear Dr. Roach: Please tell me the foods to avoid since I am a kidney-stone maker (I believe my stones are oxalate). I have had six stones to date that I have passed, and one is now lodged — and I can’t take much more. Is tea a cause of stones (since I drink quite a bit of tea, year-round)?


Dear J.J.: Kidney stones are common in men and women. Most women I have talked to who have had kids and passed a kidney stone say kidney stones are worse.

There are several different types of stones, and specific recommendations should be based on a stone analysis and the results of 24-hour urine collections; however, some simple advice can effect a significant reduction in the number of stones you may have in the future. I am going to assume for the sake of this discussion that you have had proven oxalate stones.

Some dietary factors increase stone risk, so you should reduce the amount of simple sugar (sucrose and fructose) and salt you take in. Eating less animal protein is helpful. You also should reduce your oxalate intake. You can learn more about what foods have high oxalate (there are a lot) at Brewed black tea does have a lot of oxalate (green and oolong, much less), but coffee does not. However, people who drink a lot of tea do not have higher stone risk.

Some dietary factors reduce oxalate stone risk. Increased potassium and citric acid reduce stone risk. Calcium is paradoxical: Dietary calcium reduces stone risk, but supplemental calcium increases risk. This may be because blood levels go up quickly after a supplement, leading to high enough levels in the urine to start a stone, or it may be due to the fact that dietary calcium binds the oxalate in food (at least, that’s my hypothesis).

Perhaps the most important factor is fluid intake. Regular fluid intake throughout the day significantly reduces stone risk (perhaps that’s why tea drinking doesn’t increase stones, despite the oxalate).

Dear Dr. Roach: In a recent column about frequent urinary infections, you said that this can be caused by low estrogen levels and the lining of the urethra weakening. A friend of mine suffered with frequency and urgency for years. She usually went to a doctor, who gave her antibiotics over and over. She finally went to a urogynecologist who specializes in pelvic floor disorders, and he discovered that all the “infections” were not really infections at all. He treated her with estrogen cream, but also tested her and determined she had an overactive bladder, which he treated with medication and Kegel exercises. He gave her a list of foods and beverages to avoid. He told her that overactive bladder is very common in older women, but they rarely know that there is a treatment and think it is just a normal part of aging. Please share this with your female readers.


Dear F.M.: There are several important lessons to be found here. The first is that symptoms of infection may not be infection, so it’s important to be sure of the diagnosis. The second is that there is effective treatment for urinary symptoms, but sometimes an expert is needed. I appreciate your writing.

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