Does cinnamon improve glycemic control? Original paper

In this randomized crossover trial in participants with prediabetes, supplementing with cinnamon improved measures of glycemic control, compared to placebo.

This Study Summary was published on March 28, 2024.

Quick Summary

In this randomized crossover trial in participants with prediabetes, supplementing with cinnamon improved measures of glycemic control, compared to placebo.

What was studied?

Whether supplementing with cinnamon improves glycemic control in participants with prediabetes.

The primary outcome was the change in fasting glucose. The secondary outcomes were 24-hour glucose levels (reported as the average net area under the curve), the peak glucose level during the day, and insulin sensitivity, postprandial glucose, postprandial insulin, C-peptide, glucagon, glucose-dependent-insulinotropic-polypeptide (GIP), glucagon-like peptide 1, and triglycerides, all of which were assessed during an oral glucose tolerance test.

Who was studied?

18 participants (average age of 51; 72% women, 28% men) with obesity and prediabetes.

How was it studied?

In this 4-week randomized crossover trial, the participants supplemented with 4 grams of Indonesian cinnamon or a placebo daily. A 2-week washout period separated the conditions.

For 2 weeks before the start of the study, as well as throughout the study period, all of the participants were instructed to consume a diet that was rich in simple carbohydrates and low in fiber and polyphenols. Dietary intake was monitored using 3-day food records.

To assess glucose levels, the participants wore a continuous glucose monitor throughout the study. An oral glucose tolerance test was performed at baseline, after both 4-week conditions, and after the 2-week washout period. The participants ingested either 2 grams of cinnamon or placebo (depending on the condition they were assigned to at the time) alongside 75 grams of glucose during the tests, and the outcomes were assessed every 30 minutes for 3 hours.

What were the results?

Compared to a placebo, cinnamon reduced the 24-hour glucose level and the peak glucose level (medium effect size for both outcomes).

During the oral glucose tolerance test, the glucagon level was lower with cinnamon compared to the placebo. Cinnamon also increased the level of GIP and decreased triglycerides, compared to baseline, but these values did not significantly differ from the placebo.

Anything else I need to know?

There was an increase in fat-free mass during the cinnamon condition, compared to the placebo condition, which may have contributed to changes in glycemic control.

While interpreting the results, it’s important to keep in mind the specific diet the participants were instructed to consume. It was a “beige diet” (referring to the color of the foods the diet is primarily composed of), so the participants weren’t allowed to consume more than 3 servings per day of foods like nuts, beans, seeds, and berries or other fruits and vegetables. This approach was taken to maximize the potential benefits of supplementing with cinnamon. As such, the magnitude of benefit may be much smaller in the context of an unrestricted, generally healthy diet (e.g., the Mediterranean diet).

This Study Summary was published on March 28, 2024.