As with many initial studies, the data relates to an animal model where rats were given different levels of caffeine and different diets. However, the findings are sufficient for researchers to consider additional studies, building up to experiments using people.
Biochemically, what appears to be happening is that caffeine reduces the storage of lipids in fat cells. This reduces weight gain and slows down the production of triglycerides (a fat found in the blood and which can increase the risk of heart disease). The caffeine seems to downgrade the expression of several genes associated with obesity and lipid metabolism.
In the study, from the University of Illinois, rats that consumed the caffeine (an extract from mate tea), where found to gain 16 percent less weight compared with control rats. In addition, the test rats accumulated 22 percent less body fat. The control rats were given decaffeinated mate tea. Over a four weeks, the rats were given a diet containing 40 percent fat, 45 percent carbohydrate and 15 percent protein.
Mate tea is made from the yerba mate, a South American holly tree similar to the tea plant. It is also known as chimarrão. The leaves and twigs of the yerba mate plant are dried, typically over a fire, and steeped in hot water to make the tea.
According to lead researcher Elvira Gonzalez de Mejia: “Considering the findings, mate tea and caffeine can be considered anti-obesity agents”, adding “The results of this research could be scaled to humans to understand the roles of mate tea and caffeine as potential strategies to prevent overweight and obesity, as well as the subsequent metabolic disorders associated with these conditions.”
The research has been published in the Journal of Functional Foods, with the paper titled “Caffeine, but not other phytochemicals, in mate tea (Ilex paraguariensis St. Hilaire) attenuates high-fat-high-sucrose-diet-driven lipogenesis and body fat accumulation.”
