Here's a reason not to feel so guilty after chewing your chocolate afternoon.
Dark chocolate can give your brain, your immune system and your eyes a real boost. This week researchers published three new studies that sang the praises of this delicious treat.
Scientists in a study allowed lucky volunteers to eat a dark chocolate bar, about 1.5 ounces, and then examined their brainwaves with a machine called E.E.G. The researchers found an increase in gamma waves 30 minutes after consuming the chocolate.
"Gamma frequency is associated with neurosynchronization, in other words, neuroplasticity …. It is the highest level of cognitive processing," Dr. Lee Burk, principal investigator of this study, Neuroplasticity describes the ability of the brain to efficiently connect thoughts and ideas.
Scientists believe that gamma waves are a sign that your nerve cells are igniting on all cylinders. They can talk to each other in a way that leads to optimal learning and memory formation.
In another study Burk has studied how dark chocolate affects the immune system. Again, participants ate dark chocolate and scientists studied their blood samples for the next week. They found an increase in anti-inflammatory markers as well as an increase in T cells, infection-fighting cells. Overall, these results are "great for immunity," says Burk.
It is important to know that these two studies, with only 1
A dark chocolate bar
But another study was published in JAMA Ophthalmology, a journal published by the American Medical Association. In two different tests, they gave 30 participants two chocolate bars, dark chocolate and milk chocolate, and performed eye tests two hours later. After consuming dark chocolate, the participants had small improvements in their vision.
Most important: Improving the contrast sensitivity, ie your ability to detect the difference between objects in low light or high glare. In real life, contrast sensitivity plays a role, for example when driving at night.
It is unclear why dark chocolate affects vision; However, the authors think that it has to do with the blood vessels in the eye. Cocoa, the main ingredient in dark chocolate, has been shown to positively affect blood pressure and blood vessel function. This new research suggests that dark chocolate provides more blood flow to the back of the eye, improving vision.
But sure it's really dark – 70 percent cocoa
Before embarking on brownies and hot toffee Sundays on behalf of science, all of these studies are very specific to dark chocolate.
The researchers used dark chocolate with 70 percent cocoa, a recipe reserved for the darkest dark chocolate. This usually means that the chocolate tastes bitterer than sweet, because only 30 percent of the chocolate bar is sugar and milk.
"It's really not sweet," Burk said of the chocolate used in his study. "It's the sugar that's a candy, not the cocoa."
If your favorite chocolate bar contains only 11 percent cocoa, that means 89 percent is likely to be sugar and fat. So read the label before you claim to eat chocolate on behalf of your health.
Burk believes that dark chocolate has great potential from a health perspective. In his future research, he wants to find out if the effects of cocoa on the brain could help treat diseases such as dementia and autism.
"Chocolate can be a medicine if properly studied," he added.
Laura Shopp, M.D. is a third grader who works at Indiana University and works in the ABC News Medical Unit.