Eating chocolate may slow down cognitive decline in people at high risk of dementia, a government-funded study suggests.
Researchers at Mass General Brigham Hospital in Boston gave 500-milligram cocoa extract supplements – a handful of squares of dark chocolate – to nearly 600 adults over age 60 every day for two years.
The participants also took a series of cognitive and psychological tests before and after the trial.
Those with a poor diet – which has been shown to increase the risk of dementia, scored better on memory tests than those in the placebo group.
Researchers found that while cocoa extract did not improve cognitive function in older adults, it did show small improvements in older adults with poor diets
Cognitive decline is the gradual worsening of memory and thinking, such as memory loss, confusion, and difficulty completing tasks. It often occurs as a result of aging, so combatting it in old age can reduce the risk of developing degenerative disorders like dementia.
However, those who already had a diet filled with healthy fruits and vegetables showed no ‘statistically significant’ improvements in cognitive function compared to the placebo group.
Flavanols are a natural compound found in foods like cocoa, berries, kale, onions, and tea.
These nutrients are thought to have antioxidants with anti-inflammatory properties, which have been historically linked to a lower chance of neurodegenerative diseases like dementia because they reduce inflammation in the brain.
Cocoa, in particular, contains the flavanol epicatechin, which has been shown to reduce inflammation and degeneration in the brain.
Dark chocolate is rich in flavanols, containing about 170 milligrams per 100 grams, while milk chocolate has 75 milligrams per 100 grams. This is because dark chocolate has more cacao, the seed that cocoa is made from.
The research team evaluated the effect of cocoa extract on 573 adults over the age of 60. The average age was 70. Men made up 51 percent of the population, while women comprised the other 49 percent.
About half, 285, of the participants took 500-milligram cocoa extract supplements, which included 80 milligrams of epicatechin, while 288 participants were given a placebo.
The groups were evaluated to see if cocoa extract would improve overall cognitive function, executive function, and episodic memory – memories of a specific event.
Participants completed 11 in-person cognitive and psychological tests, as well as food questionnaires at the beginning and end of the study period.
The team found that those who took cocoa extract compared to the placebo ‘had no statistically significant benefit on global cognition over two years.’
However, they said that ‘a subgroup analysis showed suggestive benefits for cognitive function among those with poorer habitual diet quality at baseline,’ including improvements in episodic memory.
‘Lower diet quality’ was not defined, but in general, eating plans filled with fat, salt, sugar, and ultra-processed foods are considered lower quality and have been shown to raise the risk of cognitive decline, diabetes, heart disease, and cancer.
The team stated that more research is still needed to determine if larger cocoa extract doses could improve cognitive function.
The study goes directly against other recent evidence suggesting that flavanols in cocoa could improve memory and reduce the risk of developing dementia.
A study published in May in the journal PNAS Neuroscience found that 500 milligrams of cocoa flavanols slowed and improved age-related mental decline, which is not as severe as disorders like dementia.
Additionally, another study found that flavanols improve learning task results in adults ages 50 to 75.
The study was supported by the National Institutes of Health (NIH) and sweets companies Nestlé-Purina Petcare Company and Mars Edge
The research was published Thursday in The American Journal of Clinical Nutrition.