Cinnamon poses no risk to kidneys

Dear Dr. Roach: I have had slightly elevated glucose levels (104-109) for several years. I found a dietary supplement of cinnamon, vitamin D and chromium. I took the directed amount for a period of time and had a glucose test of 61. I don’t know if it was a fluke or not. A recent A1C test came in at 5.9%. I backed off that dosage and now take only half three or four times a week. My glucose has gone back up.

I have also had slightly elevated creatinine levels (1.3-1.6) in the past. This was the case before starting the cinnamon supplement. My creatinine readings have largely been stable since starting the product. Can you tell me if this product is safe and whether it could adversely affect my kidneys?

D.P.

Answer: The A1C test looks at average blood sugars over the past two months or so. Your level is in the prediabetes range, which puts you at high risk for developing diabetes.

Cinnamon was marketed as a natural treatment for diabetes some years ago, and one analysis of studies found that it reduced the average blood sugar by about 9 points, which corresponds to roughly an A1C lowering of 0.3%, which would be enough to make your elevated level go into the normal range. Unfortunately, another review of the published studies found no benefit at all on glucose, A1C or insulin levels using cinnamon supplements.

Similarly, the evidence for chromium is suggestive, but not definitive. One review showed that chromium improved blood sugar in people with diabetes, but reviewers noted the studies were mostly poor quality. Giving more vitamin D to people who are not deficient did not help improve diabetes control.

A single blood sugar reading could be a fluke, and you would want to see a significant pattern in blood sugar levels or a sustained drop in your A1C before concluding that any therapy — prescribed or over the counter — was effective.

At reasonable doses, cinnamon, chromium and vitamin D are all safe. There is no risk of kidney damage when taken as directed. Still, a healthy diet and regular exercise are much more likely to have beneficial effects on diabetes control than a supplement.