Doc: At 90 pounds, chemo patient should skip fasting

Keith Roach
To Your Health
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Dear Dr. Roach: My daughter-in-law has stage 1 breast cancer and has just started her chemotherapy. I am concerned about her decision to fast for two days before and one day after each treatment. She weighs only 90 pounds, and fasting while you are trying to fight cancer does not sound like a good idea. What is your opinion of fasting during chemotherapy?


Dear K.B.: In theory, fasting may make cancer cells more susceptible to chemotherapy, and there have been studies in mice suggesting this approach might have value. However, during chemotherapy, the whole body needs good-quality nutrition, and I could not recommend fasting for someone who weighs so little, nor could I recommend two full days of fasting before chemotherapy. Until there is clear evidence that intermittent fasting is of benefit, I don’t recommend it. Your daughter-in-law, in particular, is not a good candidate, being so very thin (assuming she is of near-normal height).

Dr. Roach writes: A recent column from a woman complaining of yawning after 10 minutes in her husband’s car generated a remarkable amount of mail. I had concerns of it being due to allergies. Most readers brought up one of two concerns: Could there be a carbon monoxide leak, and could her symptoms be due to a cabin air filter in need of cleaning or replacement?

Carbon monoxide poisoning is a serious, even potentially fatal possibility. Symptoms of carbon monoxide poisoning are varied, but the most common early symptoms are headache, nausea and vomiting. With greater exposure, confusion, chest pain and loss of consciousness occur. Yawning is listed in a few sources I’ve seen as a possible symptom of carbon monoxide poisoning. The fact that only the reader, not her family, had symptoms does not rule out the possibility of carbon monoxide poisoning.

I am not a car expert, but I know who is, so I asked Ray Magliozzi from the “Car Talk” radio show and newspaper column to comment, and in his unique style, he wrote:

“My wife starts yawning when I talk to her for more than 10 minutes, too.

“If it’s not allergies, my greatest concern is that carbon monoxide is getting into the vehicle because of an exhaust leak. Unfortunately, that’ll put you to sleep — in the same way the family dog got put to sleep. You don’t say how old the used car is. Usually, an exhaust leak like that would be more likely in a very old car, with a lot of rust. But it’s definitely worth checking before you write it off as allergies.

“You can buy a cheap CO detector for about $20. They’re often used in small planes, where exposure could be fatal. It’s probably allergies if no others are symptomatic, but an arterial blood test will tell. I had one once: It wasn’t fun. Does opening a window help? I would have my mechanic check for an exhaust leak near the manifold. Those gases can easily find their way into the passenger compartment via the cowl, where fresh air gets pulled in. How about sitting in the car for an hour or so with the engine off and seeing what happens? I’m guessing outgassing noxious fumes, especially from the dashboard and seats — is the culprit.”

I thank Ray for his automotive advice, and will note that arterial blood gas testing is the gold standard for diagnosing carbon monoxide poisoning, but this needs to be done soon after exposure. I also think changing cabin air filters is a good idea.

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