The inability to properly regulate insulin, control blood sugar and utilise carbohydrates as a fuel is one of the problems that is increasingly being seen as a factor in weight gain. Called syndrome X or metabolic syndrome, this common condition can result in weight gain, and if left unchecked can ultimately lead to the development of type 2 diabetes and cardiovascular disease. One solution is a reduction in carbohydrates and an increase in the protein content of the diet as discussed in a previous article (here). Exercise is also pivotal in reducing the deleterious effects of metabolic syndrome. In addition, a number of herbs and spices may have a positive effect in treating metabolic syndrome. Of these, cinnamon appears to to be one of the most promising. If cinnamon lowers blood sugar levels, this may explain its reported effects regarding satiety and weight gain, that are beneficial in treating metabolic syndrome.
Cinnamon is a common spice which contains polyphenols which may posses a modulatory effect on insulin. Although the mechanism of action of the cinnamon polyphenols on insulin is not fully understood, the physiological effects of cinnamon as a whole spice are reasonably well established. For example, a study published in the American Journal of Clinical Nutrition in 2007 showed that an intake of 6g of cinnamon in rice pudding reduced the rate at which food left the stomach after a meal1. The study authors also measured the postprandial glycaemia of the subjects and reported that cinnamon lowers blood sugar levels significantly. However, the reduction in blood glucose was unlikely to be solely due to the reduction in gastric emptying. The increased transit time for the food could not account for the size of the reduction in blood glucose levels seen. The fact that cinnamon appears to be able to improve insulin receptor function in rat models would suggest that it is also able to modulate the action of insulin to lower blood sugar levels.
To investigate the effects of cinnamon further, the same authors published a follow up paper in the same journal in 20092. This time they fed healthy subjects 3 grams of cinnamon with rice pudding. The effect of the cinnamon was to decrease the amount of insulin released in response to the meal. At this lower 3 gram dose, the authors did not record any significant changes in gastric emptying or blood glucose levels and concluded that the higher 6 gram amount was required for these effects. They also used a low 1 gram dose and found this did not produce any beneficial changes. The fact that cinnamon can lower insulin and blood sugar levels might suggest that it would be a suitable food to help regulate body weight. Indeed, research has demonstrated that cinnamon consumption in the diet can result in increases in lean body mass as well as reduced body fat levels in human subjects. That potentially cinnamon lower blood sugar through an action on insulin therefore seems justified.
Taken as a whole these data suggests that cinnamon lowers blood sugar levels. In human trials, studies tend to have used cinnamon in the 1 to 6 gram range, the upper dose being equivalent to about 1 heaped teaspoon. It appears that this higher dose is needed to see the most beneficial effects. Of particular interest is one study that demonstrated that after the consumption of cinnamon for 40 days, the glucose lowering effect remained even after a 20 day abstinence from the spice3. This would tend to suggest that the effects are long lived and that cinnamon does not need to be consumed every day to gain a beneficial effect. Cinnamon is safe, widely available and cheap. Because cinnamon lowers blood sugar it should be included in the diet where appropriate if blood sugar control is an issue, or for improved health. However, it would perhaps not be the best idea to have the cinnamon sprinkled on a doughnut.
RdB
