The health benefits of cocoa have been in the news again, and that's good news for me! As a lover of dark chocolate I'm always looking for evidence that it might be good for my health. But I'm not gullible enough to make the leap of faith about the benefits of chocolate just from the headlines. Instead, I take the time to read the entire study to find the bitter-sweet truth.
Here are the details from the most recent study in case you didn't get around to reading it.
Research Hypothesis: Cocoa flavanols might improve cognitive function in subjects with mild cognitive impairment.
Where Conducted: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
Where Published: American Heart Association's journal Hypertension. 2012;60:794-801
Study Design: Double-blind, parallel arm clinical trial
Subjects: 90 people over age 65 in generally good health with no known cardiovascular disease, but with mild cognitive impairment (MCI). They were randomly assigned into one of 3 groups.
Protocol: Subjects were given a diary-based cocoa drink once daily for 8 weeks. The drinks contained different levels of cocoa flavanols: 990 mg (high), 520 mg (intermediate) or 45 mg (low). The diets of the participants were controlled to eliminate other dietary of sources of flavanols, but they otherwise maintained their usual diets.
Cocoa Product: The study used a specially prepared cocoa powder developed by Mars, Incorporated that supplied the required amounts of flavanols but were otherwise nutritionally the same.
Measurements: Tests of cardiovascular risk factors and neuropsychological function were done at baseline and at the end of the 8 weeks, including tests of that measure executive function of the brain, working memory, short-term memory, long-term episodic memory, processing speed and global cognition.
Results: Participants drinking the high and intermediate flavanol drinks had significantly higher overall cognitive scores than those getting the low flavanol cocoa drink. Their scores were significantly improved in working memory, verbal memory, task-switching and the ability to relate visual stimuli to motor responses.
Insulin resistance, blood pressure and oxidative stress measurements also improved among subjects in the high and intermediate flavanol groups.
Interpretation: The researchers believe the cognitive benefits were related primarily to the improved insulin sensitivity of the subjects in the high and intermediate groups since it had the highest correlation with the outcomes. The improvements in blood pressure and blood flow also may have contributed to the results since they affect brain function.
Conclusion: While improvements in cognitive function were seen over a relatively short period of time in these subjects, further studies are needed to determine if regular consumption of cocoa flavanols is effective in reversing or slowing down the loss in cognitive function in younger populations, how long the positive effects might last, and what amount of flavanols from what source can provide these benefits.
Commercially available cocoa mixes and dark chocolate on the market have not been tested for their flavanol content and vary greatly.
As I've said before, nutrition research is a slow process. Rarely does a single study change our understanding of how nutrients impact health or what foods we should eat. But with each new study we get another piece of the puzzle and I'm more convinced than ever that cocoa flavanols are good medicine.