In a related study, extracts of cloves also were found to improve the function of insulin and to lower glucose, total cholesterol, LDL and triglycerides in people with type 2 diabetes. Earlier studies had shown these positive effects in laboratory studies; the study presented at Experimental Biology provides the first evidence of these beneficial effects in humans taking the equivalent of one to two cloves per day.
Earlier studies in the laboratory of one of the co-authors of all these papers, Dr. Richard A. Anderson, Beltsville Human Nutrition Research Center, United States Department of Agriculture, had shown that the equivalent of a quarter to half a teaspoon of cinnamon given to humans twice a day decreased risk factors for diabetes and cardiovascular disease, including glucose, cholesterol and triglycerides, by 10 to 30 percent. These new studies showing cinnamon's ability to block inflammation extend our understanding of the potential for the spice, says Dr. Anderson. As an anti-inflammatory agent, cinnamon may be useful in preventing or mitigating arthritis as well as cardiovascular disease. And as scientists increasingly understand the relationship between inflammation and insulin function in Alzheimer's (causing some to refer to the neurodegenerative disease as "type 3 diabetes"), cinnamon's ability to block inflammation and enhance insulin function may make it useful in combating that disease as well.
The cinnamon and clove studies presented April 4 at Experimental Biology 2006 in San Francisco are part of the scientific program of the American Society for Nutrition, Inc. The three studies are:
The people with diabetes who had been in the experimental group then were taken off clove supplementation and, after 10 days, their glucose, triglycerides, total cholesterol and LDL measured. Although these had begun to rise somewhat, all remained significantly lower than at the beginning of the study. Dr. Khan says the finding that intake of 1 to 3 grams of cloves per day lowered risk factors of diabetes without changing HDL concentration suggest strongly that cloves are beneficial for people with type 2 diabetes. Co-authors of the study in addition to Dr. Khan and Dr. Anderson are Dr. Syed Saceed Qadir, Agricultural University, Peshawar, Pakistan, and Dr. Khan Nawaz Khattak, HMC, Hayatabad, Peshawar, Pakistan. The research was supported by the Higher Education Commission of Pakistan.
The effect of cinnamon is a major research interest in Dr. Anderson's laboratory, where human studies are now taking place looking at how this ingredient can improve insulin functioning in women with polycystic ovary syndrome (a disease of insulin sensitivity in which perturbed hormone levels cause difficulty in getting pregnant, among other problems), people with type 2 diabetes and the prediabetic metabolic syndrome; and people who are very obese (because Dr. Anderson believes that improving insulin function will lead to improvements in weight and lean body mass).
A post doctoral fellow in the Anderson laboratory also is beginning to investigate whether improving insulin functioning will decrease the chance of developing Alzheimer's disease.
Two final bits of advice from Dr. Anderson: First, eating great quantities of cinnamon straight from the can is not a good idea. Table cinnamon is not water soluble, meaning it can build up in the body with unknown consequences. Second, the powered cinnamon has another limitation. Dr. Anderson's personal 60-point decline in total cholesterol occurred only after he switched from sprinkling cinnamon on his breakfast cereal to taking it in a capsule. Saliva contains a chemical harmful to cinnamon.
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