ARS | Publication request: Bay Leaves Improve Glucose and Lipid Profile of People with Type 2 Diabetes

Submitted to: Plant Foods for Human Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 5, 2008
Publication Date: December 27, 2008
Citation: Khan, A., Kaman, G., Anderson, R.A. 2008. Bay Leaves Improve Glucose and Lipid Profile of People with Type 2 Diabetes. Plant Foods for Human Nutrition.

Interpretive Summary: Type 2 diabetes mellitus is a chronic disorder of sugar metabolism resulting from decreased function of insulin or insulin resistance. There are usually adequate amounts of insulin but the insulin has reduced effectiveness. Although the causes of type 2 diabetes and cardiovascular diseases are multifactorial, diet definitely plays a role in the incidence and severity of these diseases. The dietary components beneficial in the prevention and treatment of these diseases have not been clearly defined, but it is postulated that spices may play a role. We have shown previously that aqueous extracts of spices such as cinnamon, cloves, bay leaves, and turmeric display insulin-enhancing activity in vitro. Studies in humans have confirmed our results for cinnamon and this study confirms that bay leaves are also of benefit to normalize sugar and fat metabolism in people with type 2 diabetes. Forty people with type 2 diabetes were divided into 4 groups & given capsules containing 1, 2, or 3 g of ground bay leaves per day for 30 days or a placebo followed by a 10 day washout period. All three levels of bay leaves led to significant improvements in blood sugar, total cholesterol, LDL and HDL cholesterol, and triglycerides. These data are important to scientists, medical personnel, and the millions of people world-wide who have early signs of diabetes and elevated blood fats.

Technical Abstract: Bay leaves (Laurus nobilis) have been shown to improve insulin function in vitro but the effects on people have not been determined. The objective of this study was to determine if bay leaves may be important in the prevention and/or alleviation of type 2 diabetes. Forty people with type 2 diabetes were divided into 4 groups & given capsules containing 1, 2, or 3 g of ground bay leaves per day for 30 days or a placebo followed by a 10 day washout period. All three levels of bay leaves reduced serum glucose with significant decreases ranging from 21 to 26% after 30 d. Total cholesterol decreased 20 to 24% after 30 d, with larger decreases in LDL cholesterol of 32 to 40%. HDL cholesterol increased 29 and 20% in the groups receiving 1 and 2g of bay leaves, respectively. Triglycerides also decreased 34 and 25% in groups consuming 1 and 2 g of bay leaves, respectively, after 30 d. There were no significant changes in the placebo group. In summary, this study demonstrates that consumption of bay leaves, 1 to 3 g/d for 30 days, decreases risk factors for diabetes and cardiovascular diseases and suggests that bay leaves may be beneficial for people with type 2 diabetes.