DEAR DR. DONOHUE: All my blood tests have come back normal except for potassium. It’s low. Why? My doctor told me to drink orange juice and eat bananas. How much orange juice and how many bananas? How does low potassium affect you? I don’t feel any different than I ever did. – G.G.

The mineral potassium has many roles. It keeps the heart beating, nerves firing and muscles contracting.

Significant loss of potassium brings on fatigue, muscle weakness, muscle cramps, nausea, vomiting and abnormal heartbeats. With a significant potassium deficit, it’s close to impossible to restore a normal potassium level with potassium-rich foods like bananas and oranges; it’s necessary to take potassium supplements.

Potassium foods can restore a normal level if the deficit isn’t all that great.

The key to low potassium is finding out why it’s low and correcting that problem.

A leading cause of a potassium deficit is potassium loss from vomiting or diarrhea. You don’t mention suffering from either, so this can’t apply to you.

Kidney disorders are another cause.

The kidney keeps a close watch on the body’s potassium stores. It adjusts how much it eliminates in the urine according to how much the body has on hand. Many kidney illnesses ruin the kidney’s ability to regulate body potassium levels. I can’t believe you have serious kidney problems, or your doctor would have mentioned them and they would have shown up on your lab tests.

Adrenal gland problems also can upset body potassium balance. Other signs of such problems are obvious, and you have none of them.

Do you take a diuretic (water pill)? Many water pills deplete body potassium stores. If you do, call the doctor and ask if a different one would be better for you. If you don’t, ask the doctor what’s causing your low potassium.

The booklet on sodium and potassium discusses these important minerals in detail. To order a copy, write: Dr. Donohue – No. 202, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: Last month, after a number of tests, my doctor put me on Provigil. I felt like my life had been handed back to me.

It was wonderful. I had to take a sleep test before I started it, and the test showed I had sleep apnea. But it does have a side effect – edginess.

Today, for example, trying to cash a CD became an ordeal because of the bureaucratic rules the bank demanded for identification. I got so angry that I thought I would have a heart attack. This is something I normally would have passed over. I’ve told my doctor, but I haven’t told him the extent because I don’t want to stop the Provigil.

I suppose I could cut the dosage or get these matters taken care of early in the day, before taking it. Do you have any suggestions? – L.J.

What a pleasure to hear the endorsement of a medicine. Most letters recount the exact opposite: They’re about the terrible things that happen from taking medicine. Both of your solutions sound sensible to me.

Or you might try making a hasty exit when you feel your anger rising. Frankly, I respond with the same vehemence you do when confronted with similar situations, and I’m not on Provigil.

DEAR DR. DONOHUE: For osteoporosis, I take calcium pills. I also have aortic stenosis, which, I understand, is associated with calcium deposits. Should I cut back on my calcium intake? – S.R.

The calcium you get from your calcium tablets isn’t going to add to the calcification of your aortic valve. That’s something the body does on its own, with or without calcium supplements. It’s trying to patch up a valve deformity, and it takes calcium from the body’s calcium bank – bones. Your oral calcium isn’t going to affect valve calcification one bit.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from

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