Doc: Some precautions for those with one kidney

Keith Roach
To Your Health

Dear Dr. Roach: My husband had an MRI about 10 years ago before back surgery, and we were informed that he has only one functioning kidney. The other is atrophied and useless. We were not told that he needed to take any precautions, but now I wonder if we should have asked more questions.

Are there any medications or foods he should avoid? He is 54 and otherwise healthy.


Dear S.H.: I’m not sure why your husband’s kidney is atrophied. There are several possible causes, but the most likely is congenital dysplasia, meaning your husband likely had this at birth. Chronic infection is another cause, but normally this is comes with symptoms and isn’t incidentally discovered, as your husband’s apparently was.

People with one functioning kidney generally have no problems and need no special diet or medication restrictions. The other kidney increases its function to (mostly) make up for the other kidney’s absence.

In studies of those who’ve donated a kidney, the rate of progression to end-stage kidney disease was small but slightly higher compared with people with two kidneys. The risk of high blood pressure may be slightly higher.

For someone in your husband’s situation, I’d recommend good general care of his remaining kidney — a healthy diet, avoiding dehydration and staying away from high doses of medicines that affect the kidney, such as ibuprofen and Tylenol. In very large doses over years, they can cause kidney disease. Occasional doses are fine.

Dear Dr. Roach: My son salts everything, even his salads. I also have a brother who has had three heart attacks and eats two or three bags of chocolate-covered nuts daily. According to him, his doctor says that is good, since sugar is energy.

I don’t understand. We need salt in our diet, but sugar?


Dear P.K.: It is true that we need some salt in our diet, but in a typical Western diet, we get far more than we need. Adding salt to food is likely to result in a great excess of salt, compared with what is considered optimal. In most people, this results in only a few points in blood pressure, but in some people, it results in a much greater increase in blood pressure. There is at least one study that has shown that stroke risk is higher in people who consume large amounts of salt, even if they have normal blood pressure when compared with people who use little salt.

Nuts and dark chocolate are healthy — if eaten in reasonable quantities. Two or three bags (I don’t know how big the bags are) sounds to me like it might be a lot more than ideal. You also didn’t tell me if the chocolate is dark (which may have some small health benefits, or at least not be unhealthy, having little sugar) or milk (which has far more sugar and milkfat), which is not so healthy.

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