function (Malin DH et al. 2010).
Rats are ideal for such studies because they age so much more rapidly than humans, allowing researchers to see changes in mere months rather than years or decades.
This study follows one by the same team, which found brain benefits in aging rats fed a blueberry-enriched diet for four months (Goyarzu P et al. 2004).
Elderly rats fed a blueberry-enriched diet for one month showed improvements in memory, as measured in a maze test.
Better yet, eating a blueberry-enriched diet for two months prolonged the benefits after the diet was stopped … and the mental performance of the aging rats improved even more, to the higher level seen in younger rats.
As the researchers wrote, “This illustrates a surprisingly prompt and powerful effect ... [of blueberry-enriched diets].” (Malin DH et al. 2010)
They called attention to some promising implications for people:
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“First, the present results suggest that even a relatively brief blueberry diet might produce measurable benefits.”
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“Second, the benefits of several months of the diet might be maintained for a considerable period after the diet is interrupted.”
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“Third, blueberry supplementation might possibly reverse some degree of memory impairment that has already developed.”
And they raised the question that will occur to many readers: “This raises the possibility that this sort of nutritional intervention might still be beneficial even after certain memory deficiencies have become evident.” (Malin DH et al. 2010)
We encourage researchers to test this hope in human clinical trials, sooner rather than later.
How could berries help deter dementia?
Human diets rich in blueberries have previously been linked to a reduced risk of Alzheimer’s, and the berries’ benefits are believed to flow from their polyphenol content … in particular, two kinds found in most berries, called anthocyanins and flavanols.
We still don’t know how anthocyanins and flavanols might enhance memory and other brain functions … but in rats, they’re proven to cross the blood-brain barrier and reach areas associated with cognitive performance (Andres-Lacueva C et al. 2005).
As the Houston-Boston team noted, prior studies suggest that berry-borne anthocyanins and flavanols may enhance existing neuronal connections (i.e., links among brain cells), improve cell-to-cell communications, and stimulate growth of brain cells.
We also know that berry-borne polyphenols exert “nutrigenomic” effects on cellular genetic switches called nuclear transcription factors, such as Nf-kappaB (Goyarzu P et al. 2004).
Specifically, they exert damping effects on Nf-kappaB and other pro-inflammatory genetic switches, and may thereby discourage the chronic low-level inflammation associated with Alzheimer’s and other degenerative diseases.
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