Consumption of dark chocolate helped rid the brain of the effects of chronic stress
Iranian physiologists from Isfahan University of Medical Sciences analyzed how dark chocolate consumption affects brain function under conditions of chronic stress. Using rodents as an example, they studied the effect of different dietary regimes on synaptic activity and plasticity of the cA-1 layer of the hippocampus, a part of the limbic system of the brain involved in the transition of short-term memory to long-term and spatial memory, as well as the formation of emotions. The findings are published in the journal Nutritional Neuroscience.
Dark chocolate needs no introduction, as its history, according to some data, is five and a half thousand years old: it was then that cacao fruit began to be consumed by representatives of the Mayo-Chinchipe culture in modern Ecuador. Subsequently, the Mayans drank it as a bitter fermented drink, mixed with spices or wine.
Dark chocolate contains 50 to 90 percent cocoa powder, cocoa butter and sugar, while milk chocolate contains only 10 to 50 percent cocoa powder, cocoa butter, some form of milk and sugar. Cream fat, vegetable oils, artificial colors and flavorings may be added to a lower quality product. White chocolate has no cocoa powder at all - just its butter, sugar and milk.
Because dark chocolate has more cocoa beans, which are rich in flavanols, it is healthier. Flavanols - plant polyphenols - support the production of nitric oxide in endothelial cells, which helps relax smooth muscles in the walls of blood vessels, improve blood flow, thereby lowering blood pressure and inhibiting the adhesion of platelets to the vessel wall. In addition, previous scientific work has shown that flavanols in chocolate can improve insulin sensitivity and reduce the risk of developing diabetes.
The test subjects in the new study were 35 rats, which were divided into five groups of seven individuals. Each followed a different diet regimen corresponding to "forced," "optional" and "restricted" stress. "Stressed" animals received only chocolate, while rats on the optional diet received unlimited food and/or chocolate. Rats exposed to stress on the restricted diet ate only four grams of dark chocolate per day," the scientists wrote.
The researchers assessed the excitatory postsynaptic potential in the rodents, measured their body weight and food intake at the beginning of the experiment and afterward. As a result, it turned out that dark chocolate helped the animals to reduce weight and the amount of food consumed. The effect was most pronounced in groups with forced and limited stress induced by diet: in such subjects, the harmful effects of chronic stress on synaptic activity and hippocampal plasticity, as well as on learning and memory, were reversed.
In the future, the scientists plan to confirm their results in humans and obtain reliable evidence of the effects of dark chocolate on the brain and cognitive abilities.