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Your Good Health: Continuous glucose monitor tracks diet, exercise

A continuous glucose monitor gives a major advantage of providing real-time glucose readings without having to draw blood.
Dr. Keith Roach

Dear Dr. Roach: I am a 66-year-old man who has been exercising regularly and eating much better these past few years after my doctor warned me that I was prediabetic. Still, after initial success, my A1C levels have been creeping upward again.

I’ve been thinking there is something in my diet that isn’t as healthy as I think it is. So many foods that are advertised as healthy really aren’t. And I have been told by professional dieticians that everyone reacts a little differently to various food items anyway.

What do you think of the idea of trying a continuous glucose monitor (CGM) to see if I can find out if there is something in my diet that is not as good for me as I think it is?


A CGM is an excellent way of monitoring blood sugar. The device is placed by the user (a diabetes educator or a nurse can teach you, or there are instructional videos online), and the device will record blood sugar levels every 5-15 minutes for one to two weeks. (There are also implantable devices that now last three to six months.)

This gives a major advantage of providing real-time glucose readings without having to draw blood. Some devices communicate directly with a user’s smartphone. A CGM may now be bought over-the-counter without needing a prescription.

CGM devices are particularly important for people with Type 1 diabetes, but are also clearly indicated for people with Type 2 diabetes who frequently have low blood sugar levels. Most devices are able to warn the user if the readings are too low or are headed down quickly, even if they’re not yet abnormal. In my opinion, the use of a CGM in these circumstances is the new standard of care.

The use of a CGM in other situations is not so clear. I do understand why you are interested. I think that with a CGM in combination with a very meticulous food and exercise log, you could find out what foods you are eating that are raising your blood sugar. You can also find out how powerful your response to exercise is.

I recommend this only for someone who is really motivated and comfortable analyzing complex data — and who doesn’t mind paying out of pocket. I don’t think you would need to use one all the time. You just need to get an idea of how best to eat and exercise for your blood sugar levels.

Dear Dr. Roach: Flavinoid supplements work amazingly well to reduce ringing in the ears for those with tinnitus.


While I’m glad you had a good response, the preponderance of evidence doesn’t support the use of supplements to treat tinnitus. Manganese and Lipo-Flavinoid Plus were studied in a 2016 controlled trial, and neither was found effective. In an online survey of supplements including Ginkgo biloba, lipo-flavoinoid, vitamin B12, zinc, manganese, and melatonin, 71% found them ineffective; 19% found a benefit; and 10% found that their symptoms worsened.

I don’t recommend dietary supplements for treating tinnitus.

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