The results of
many animal and cell experiments support the notion that foodborne
antioxidants protect and enhance brain function, with positive
findings attached to tea, berries, turmeric, grapes, and cocoa,
among other foods and fruit juices rich in polyphenol-type flavonoid
antioxidants.
The positive
effects seen in lab and animal studies range from beneficial effects
on cell signaling to direct antioxidant effects on cell-damaging
free radicals and increases in blood flow to the brain.
But surprisingly
few studies have looked for confirming evidence from human
population or clinical studies.
A French team now reports that diets rich in flavonoids – the
antioxidant compounds in fruit, vegetables, coffee, tea, and
chocolate – could reduce the decline in mental function associated
with aging.
The researchers, based at INSERM – France's equivalent of the US
National Institutes of Health – recruited 1,640 subjects with an
average age of 77 who showed no signs of dementia at the start of
the study.
The participants’ estimated intake of flavonoids was assessed using
diet surveys administered four times over a 10 year period.
Their level of cognitive function was measured using standard tests.
After adjusting the results for age, sex, and education level,
the French group linked higher flavonoid intake with better mental
performance at the start of the study and less risk of mental
decline over time.
The people with the highest flavonoid intakes displayed better brain
function than those with the lowest intakes.
While these
encouraging results need confirmation in controlled clinical trials,
they fit with everything we know about the effects of flavonoids at
the cellular level, and their general ability to neutralize
cell-damaging free radicals and increase blood flow to the brain.
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