Chocolate just got a little bit sweeter.
New research published in the journal Appetite suggests habitual chocolate consumption is positively associated with cognitive performance — the first cohort study to examine associations between longer-term chocolate eating and brain function, according to researchers. Prior studies have shown chocolate and cocoa flavanols can improve cardiovascular health, but less is known about ways chocolate impacts human cognition. The present study aimed to learn more about the treat's neurocognitive benefits.
Researchers used data collected during the sixth wave of the Maine-Syracuse Longitudinal Study (MSLS), where participants living in Syracuse, N.Y., were measured for dietary intake and risk factors for cardiovascular disease. For the dietary portion, participants answered a questionnaire that measured for how frequently they consumed a list of foods, including meat, rice and pasta, fruit, vegetables, chocolate, other snack-type foods, as well as beverages like water, coffee, and alcohol. The answers ranged from never to once or more per day.
To measure for cognitive function, participants were given a series of tests designed to measure a wide range of cognitive domains: visual-spatial memory and organization, scanning and tracking, verbal episodic memory, and working memory. The Mini-Mental State Examination was also included to measure for mental status — high scores indicated better performance, researcher wrote.
When combining dietary intake with cognitive tests, individual demographics, and physical health assessments, researchers found chocolate consumption was positive associated with cognitive performance "irrespective of other dietary habits." The finding held up even when researchers adjusted for participant's cardiovascular risk factors, including total and LDL-cholesterol, glucose levels, and hypertension.
Curious to see if cognitive performance predicted chocolate consumption, researchers performed a second analysis on a sample of participated who completed the dietary questionnaire, as well as cognitive tests given during earlier waves of MSLS. The results found no significant associations between chocolate intake and performance.
So what's the catch?
Well, chocolate was not differentiated according to type: milk, dark, or white chocolate. Some studies suggest there's an equal amount of methylxanthines in chocolate — a combination of caffeine and theobromine that's been associated with improving alertness and cognitive function — but an overwhelming amount of chocolate-related research shows preference for dark chocolate. The reason is dark chocolate tends to have higher levels of flavanols.
Flavanols are a subgroup of flavonoids, with cocoa flavonoids being the most common, researchers said; high levels of flavanols are also found in tea, red wine, and fruits such as grapes and apples. There’s only seven to 15 percent of cocoa in milk chocolate compared to 30 to 70 percent in dark chocolate. Put it another way: One hundred grams of dark chocolate contains approximately 100 milligrams of flavanols compared to 15 mg for the same amount of milk chocolate.
Without specifying how participants were soothing their sweet tooth, researchers can't say for sure which type(s) of chocolate improve cognitive performance. But, they speculate they can rule out white chocolate: In 2012, researchers found the distribution share of chocolate in the United States by favorite chocolate type was 57 percent milk chocolate, 35 percent dark chocolate, and 8 percent white chocolate.
It's worth noting, too, researchers simply measured how many times participants ate a certain group, not the quantity during each time. We neither know the type of chocolate nor the amount to eat to reap these potential benefits, at least not yet.
"It is evident that nutrients in foods exert differential effects on the brain. As has been repeatedly demonstrated, isolating these nutrients and foods enables the formation of dietary interventions to optimize neuropsychological health," researchers wrote. "Adopting dietary patterns to delay or slow the onset of cognitive decline is an appropriate avenue, given the limited treatments available for dementia. The present findings support recent clinical trials suggesting that regular intake of cocoa flavanols may have a beneficial effect on cognitive function, and possibly protect against normal age-related cognitive decline."
In the future, researchers suggest there be "longer-term clinical trials to shed further insight into this association between chocolate," cocoa flavanols, and neuropsychological health. They're also interested to see how the amounts of chocolate people eat affects cognition, and the effects of when foods high in flavonoids are consumed in combination.
Source: Crichton GE, Elias MF, Alkerwi A. Chocolate intake is associated with better cognitive function: the Maine-Syracuse Longitudinal Study. Appetite. 2016.
Updated | The specifics of dietary intake measures.