A study suggest that two cups of hot cocoa a day may keep older people’s brain sharp and improve their memory.

However, people shouldn’t start bottling up hot cocoa drinks to help them remember birthdays and names, as cautioned by the researchers.

Dr. Farzaneh A. Sorond, lead author of the study from Harvard Medical School in Boston, and his colleagues observed 60 people who are clear of dementia with a mean age of 73.

Each participant was asked to drink two cups of hot chocolate drink everyday for a month and to avoid taking in any other chocolates to make the evaluation more accurate. After a month, they were asked to take memory and thinking skills assessments and undergo ultrasound test to note the amount of blood flow to the brain during the examinations.

Sorond found out of that out of the 60 participants, 18 displayed impaired blood flow before the study. By the end of the 30-day study, the 18 participants had an 8.3 percent progress in the blood flow to the working areas of the brain. It simply means there was improvement on their thinking skills.

The researchers wrote in the report, "We're learning more about blood flow in the brain and its effect on thinking skills. As different areas of the brain need more energy to complete their tasks, they also need greater blood flow. This relationship, called neurovascular coupling, may play an important role in diseases such as Alzheimer's."

“It's possible that even small amounts of flavanols make a difference for people with impaired blood flow or that the caffeine in cocoa played a role in their improvement,” Sorond said in a talk with Reuters.

However, she warned that the new study doesn’t guarantee that drinking hot cocoa will improve thinking and blood flow.

Another thing they have observed was that people with the impaired blood flow showed improvement during the time of the test of working memory, with the duration of 167 second at the beginning of the study down to 116 seconds at the end based on the ultrasound test.

This study was released in the journal Neurology.