Cinnamon and cloves: Benefits in diabetes probed

Shelley Wood

April 04, 2006

San Francisco, CA - New research debuting at the Experimental Biology 2006 meeting this week explores the cardiovascular benefits of cinnamon and cloves in diabetics. One study points to improved cardiovascular and diabetes risk factors in type 2 diabetics taking the equivalent of one to two cloves per day. Two additional studies explore mechanistic aspects of cinnamon metabolism that could help explain previously reported benefits of cinnamon in diabetics. Dr Richard Anderson (Beltsville Human Nutrition Research Center, US Department of Agriculture), whose laboratory has pioneered much of the work in this field, oversaw all three studies.

In the clove study, Anderson, with first author Dr Alam Khan (Agricultural University, Peshawar, Pakistan), a former postdoctoral student, examined the effects of 0, 1, 2, or 3 g of cloves over 30 days, followed by a 10-day washout period, in 36 type 2 diabetics[1]. While there were no significant differences between the three clove doses, all participants eating cloves daily experienced significant improvements in CV risk factors, compared with those not taking cloves. HDL was unaffected by clove consumption; no changes were seen in any of the criteria measured among people not eating cloves.

30-day effects of clove consumption (any dose)

Parameter Baseline 30 d
Serum glucose (mg/dL) 225±67 150±46
Triglycerides (mg/dL) 235±63 203±86
Serum total cholesterol (mg/dL) 273±78 239±47
LDL cholesterol (mg/dL) 175±73 145±44

To heartwire , Anderson explained that previous in vitro and laboratory studies have indicated that compounds found in cloves, like those found in cinnamon, appear to increase insulin efficiency.

"This abstract extends this work to humans and demonstrates that consumption of as little as 1 g of cloves by people with type 2 diabetes leads to improvements in blood sugar, insulin, cholesterol, and triglycerides," Anderson commented. "The major contribution of this study is that it demonstrated that consumption of cloves may be important in the alleviation of diabetes and cardiovascular diseases in humans."

The spice(s) of life?

Earlier work by Anderson's group has indicated that components of cinnamon can improve insulin function, at least in laboratory studies. As he explained to heart wire , cinnamon appears to increase insulin efficiency such that less insulin is required. "This is important, since most people with type 2 diabetes do not have too little insulin but have elevated levels of insulin that is not efficient," Anderson explained. "High levels of circulating insulin can lead to many of the secondary signs of diabetes such as nerve, kidney, and eye problems, as well as buildup of plaque in the arteries."

In one of the cinnamon abstracts presented this week, Dr Heping Cao (Beltsville Human Nutrition Research Center, MD) and colleagues report that polyphenols found in cinnamon increase two of the key components involved in insulin function: the insulin receptor that is activated when insulin binds and glucose transporter 4, a component that is responsible for sugar to enter the cell[2]. In another aspect of the research, Cao et al showed that these same polyphenols increase a molecule that inhibits inflammatory responses and therefore may be important in the prevention of inflammatory diseases, such as arthritis, autoimmunity, dermatitis, and cardiovascular diseases.

"This study provides new biochemical evidence for the beneficial effects of cinnamon polyphenols in potentiating insulin action and suggests anti-inflammatory properties of cinnamon polyphenols," Cao et al conclude.

In a second study, Dr Stephanie Mae Lampke (University of California, Santa Barbara) and colleagues used fractionation and electrospray mass spectrometry to identify the chemical structure of cinnamon polyphenols[3].

"This work demonstrates that the active components of cinnamon are polyphenol compounds that not only improve the function of insulin but also function as antioxidants, which are very important in the prevention of cardiovascular diseases," Anderson commented to heartwire .

Anderson's group is also studying the effects of cinnamon in people with impaired glucose tolerance, polycystic ovary syndrome, gestational diabetes, and metabolic syndrome.

Perhaps as a result of continuing research, sales of cinnamon and cinnamon-related products have already reached several millions of dollars, Anderson observed. "These natural compounds should be considered as part of a good diet to prevent and/or alleviate diseases such as diabetes and cardiovascular diseases," he concluded. However, he cautioned, "These natural products do not work in everyone, and at least one study has shown that with some types of cinnamon, benefits are not significant."


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