Though some studies have hinted that cinnamon may aid blood sugar control, it's too soon to recommend the spice for people with diabetes, according to researchers.
Their study of 43 adults with type 2 diabetes found that cinnamon supplements did nothing to change blood sugar, insulin or cholesterol levels over three months.
The findings, published in the journal Diabetes Care, stand in contrast to some past studies that have suggested cinnamon may help with diabetes control.
Cinnamon previously shown to change blood sugar levels
In one study of people with type 2 diabetes, for example, researchers found that those who added some cinnamon to their daily diets had a dip in their blood sugar and cholesterol levels.
Lab research suggests that cinnamon may make body cells more sensitive to insulin, a hormone that shuttles sugar from the blood into cells to be used for energy. Type 2 diabetes develops when cells lose their sensitivity to insulin.
There's also evidence that cinnamon slows digestion, which can temper the blood sugar rise that follows a meal.
How the study was done
In the new study, researchers at the University of Oklahoma in Oklahoma City randomly assigned type 2 diabetics to take either cinnamon capsules or a placebo every day for three months.
The cinnamon group took two capsules a day, each of which contained 500 milligrams of the spice. The placebo group took capsules containing wheat flour.
In the end, there were no differences in the groups' average levels of blood sugar, insulin or cholesterol, according to the researchers, led by Dr Steve M. Blevins.
Study not conclusive
The reason for the conflicting findings from this and earlier studies may have to do with differences in the study groups, Blevins and his colleagues explain.
Most patients in the current study, for example, were on various diabetes drugs; in an earlier study that found cinnamon to lower blood sugar, no patients were on any of these drugs.
The researchers conclude that more studies are needed to see how various factors - like overall diet and medication use - affect any benefits of cinnamon in managing diabetes.
"Until then," they write, "cinnamon cannot be generally recommended for treatment of type 2 diabetes in an American population." - (Reuters Health)
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