In vitro and in vivo animal studies have reported strong insulin-like or insulin-potentiating effects after cinnamon administration.

Recently, a human intervention study showed that cinnamon supplementation (1 g/d) strongly reduced fasting blood glucose concentration (30%) and improved the blood lipid profile in patients with type 2 diabetes.

The objective of this study was to investigate the effects of cinnamon supplementation on insulin sensitivity and/or glucose tolerance and blood lipid profile in patients with type 2 diabetes.

Therefore, a total of 25 postmenopausal patients with type 2 diabetes (aged 62.9 ± 1.5 y, BMI 30.4 ± 0.9 kg/m²) participated in a 6-wk intervention during which they were supplemented with either cinnamon (Cinnamomum cassia, 1.5 g/d) or a placebo.

Before and after 2 and 6 wk of supplementation, arterialized blood samples were obtained and oral glucose tolerance tests were performed.

Blood lipid profiles and multiple indices of whole-body insulin sensitivity were determined. There were no time x treatment interactions for whole-body insulin sensitivity or oral glucose tolerance.

The blood lipid profile of fasting subjects did not change after cinnamon supplementation.

We conclude that cinnamon supplementation (1.5 g/d) does not improve whole-body insulin sensitivity or oral glucose tolerance and does not modulate blood lipid profile in postmenopausal patients with type 2 diabetes.

More research on the proposed health benefits of cinnamon supplementation is warranted before health claims should be made.

J. Nutr. 136:977-980, April 2006

Kristof Vanschoonbeek^*,1, Bregje J. W. Thomassen, Joan M. Senden, Will K. W. H. Wodzig^** and Luc J. C. van Loon^*,

^* Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht, The Netherlands; Department of Movement Sciences, NUTRIM, Maastricht University, Maastricht, The Netherlands; and ^** Department of Clinical Chemistry, Academic Hospital Maastricht, The Netherlands

¹ To whom correspondence should be addressed. E-mail: K.Vanschoonbeek@HB.unimaas.nl