Published August 14, 2012
Eating dark chocolate every day may improve thinking abilities in people with mild cognitive impairment, according to a new study.
Researchers enlisted older adults to consume either low, moderate or high amounts of flavanols in a cocoa-based beverage every day for eight weeks, and a link was found between the higher amounts of flavanols and improvements in tests of cognitive function.
The higher the concentration of flavanols, the better the people did on the tests — completing them more quickly and recalling more information, the researchers found.
The study was funded by Mars, a company that makes chocolate candy.
All study participants had mild cognitive impairment, a condition in which people have problems with memory or thinking that go beyond the normal age-related decline but don't interfere with their daily activities. The condition can lead to Alzheimer's disease.
Previous research has shown that flavanols have other health benefits, including improving blood pressure and insulin resistance.
"It is yet unclear whether these benefits in cognition are a direct consequence of cocoa flavanols or a secondary effect of general improvements in cardiovascular function," said lead study author Dr. Giovambattista Desideri, director of the geriatric division at the University of L'Aquila in Italy.
For example, the improvements to the cardiovascular system may increase blood flow in the brain, leading to mental improvements, the researchers said.
The study was published Aug. 13 in the journal Hypertension.
A daily supplement
Flavanols are found in cocoa, red wine, grapes, apples and tea.
The researchers asked 90 elderly adults to drink flavanol beverages of varying concentrations for eight weeks, while the rest of their diet was controlled, to reduce their consumption of flavanols from other sources. Tests taken at the start and end of the eight-week period measured the participants' short- and long-term memories, as well as other aspects of general function.
Every year, 6 percent of those beyond age 70 develop mild cognitive impairment, the researchers noted. The condition can be a precursor to dementia or Alzheimer's disease, so reducing mild cognitive impairment also might decrease the percentage of people with these diseases, the researchers suggested, though more research would be needed to show this.
Beyond their mild cognitive impairment, the study participants were in good health, with no cardiovascular disease, the researchers said. The effects of flavanols may vary in populations already affected by cardiovascular disease, or without mild cognitive impairment.
Chocolate and Alzheimer's
Other experts disagreed with the study's conclusion.
The data showed "there was no effect on overall cognition," said Dr. Marc L. Gordon, chief of neurology at Zucker Hillside Hospital in Glen Oaks, N.Y., who researches Alzheimer's disease. The study participants showed improvements in terms of processing information and thinking faster, but Gordon said that the researchers incorrectly equated this improved speed with an overall improvement in cognitive function, and these are not necessarily the same."
And although the results are intriguing, they cannot be widely applied because the study looked at such a specific population, he added.
The results showed that flavanols may improve brain speed, which may or may not affect the development of Alzheimer's disease, and more research is needed to understand the connection, Gordon said.
American Heart Association spokeswoman Rachel K. Johnson, a nutrition professor at the University of Vermont, said it's well known that flavanols lower blood pressure, but the positive effect this may have in the brain is a relatively new finding.
While the relationship should be studied further, Johnson said, that there is no harm in adding flavanols to a diet.
Foods with flavanols are "generally healthy foods that fit in well with a heart-healthy diet," she said. It's important to note that flavanols are found in chocolate with high cocoa content, so dark chocolate is the best for health, Johnson said.
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