Older adults who eat diets high in antioxidants may not have a lower risk of dementia or stroke, according to a Dutch-based study - despite some evidence that specific vitamins have a protective effect on the brain.
The study, published in Neurology, found that people who consumed the most antioxidants - appearing in large quantities in foods such as beans, berries and nuts - were just as likely to end up having either dementia or stroke as study participants who hardly got any antioxidants.
"There is the thought that overall antioxidants might be helpful, but it's also true that if you actually look at the individual antioxidants, there's not necessarily a reason to think that one would behave exactly the same way in the body as the next," said study leader Elizabeth Devore, at Brigham and Women's Hospital in Boston.
The Netherlands-based study included 5,395 people aged 55 years and older, who reported their usual consumption of 170 different foods in 1990. Devore and her colleagues then tracked those participants over the next 14 years.
During that time, 599 were diagnosed with dementia - including 484 with Alzheimer's disease - and 601 had a first stroke.
There was also no link between total dietary antioxidants and white or gray matter volume in the brain, according to scans done on 462 of the participants.
Devore note that since the study looked only at foods consumed, it can't address whether antioxidant supplements may have an impact on stroke or dementia risk - though her team concluded it's still likely that certain individual antioxidants have positive effects on the brain.
"There have been a number of studies that have shown that higher intake of dietary vitamin E is associated with lower risk of dementia," Devore told Reuters Health. The same goes for vitamin C and stroke risk.
That suggests that people should continue eating plenty of fruits and vegetables, including berries, and seek out specific antioxidants, she said.
Vitamin E rich foods include greens such as spinach and kale, almonds, broccoli and red Bell peppers. Vitamin C rich foods include dark leafy greens, papayas, oranges and strawberries.
"For dementia specifically and stroke specifically, if you're worried about those... you should try to take in vitamin E for dementia and vitamin C for stroke.