A pretty large body of evidence indicates that berries boost brain functions … and may help prevent memory loss and other age-related declines.
That supposition gained support from a new review of the evidence published in the prominent Journal of Agricultural and Food Chemistry (Miller MG et al. 2012).
As the review's authors say, Americans' longer life spans increase the heavy toll that Alzheimer's disease – and other forms of mental decline – takes on patients, families, and health care budgets.
Loads of laboratory and epidemiological research indicate that berries benefit the brain … for example, see “Blueberries Reverse Rodents' Brain Decline,” “Berries Seen Reducing Stroke Damage,” “Berries May Offer Brain Benefits to Astronauts,” and “Berries Reaffirmed as Brain and Heart Health Allies.”
While we don't have enough clinical confirmation to prove that the brain benefits seen in animal studies extend fully to humans, the indications are good … see “Blueberries Score in Two Brain-Health Trials.”
To analyze the strength of the evidence about berry fruits, a team at the world-famous Tufts-USDA research center conducted an extensive review of the cell (test tube), animal, and human studies on the topic.
They concluded that berries help the brain stay healthy in several ways:
Protect brain cells from oxidation by free radicals.
Reduce inflammation and consequent production of free radicals.
These effects seem to flow primarily from particular polyphenol (“antioxidant”) compounds called flavanols, which occur at unusually high levels in berries (and in tea and non-Dutched cocoa and dark chocolate).
Berry flavanols influence genetic switches in cells and critical signaling pathways between brain cells (neurons).
The improvements in cell signaling wrought by dietary flavanols can inhibit unnecessary inflammation in the brain, which contributes to neuronal damage.
This effect alone helps explain evidence that berry flavanols can improve motor control and cognition (thinking, memory) in animals and humans alike.
Berry phenols seen to enhance brain “housecleaning”
Thanks to research published two years ago by researchers from the Tufts-USDA lab, we now know that berries may help the aging brain stay healthy in a crucial, but previously unrecognized, way.
The landmark 2010 Tufts-USDA study found that berries – and possibly walnuts and other high-polyphenol foods – activate the brain's natural “housekeeper” mechanism (Poulose SM et al. 2010).
It looks like berry polyphenols clean up and recycle toxic proteins linked to age-related memory loss and other mental decline.
Cells called microglia are the brain's housekeepers. In a process called autophagy, they remove and recycle biochemical debris that otherwise would interfere with brain function.
“But in aging, microglia fail to do their work, and debris builds up,” explained lead author Shibu Poulose, Ph.D. (ACS 2010)
“In addition, the microglia become over-activated and actually begin to damage healthy cells in the brain. Our research suggests that the polyphenols in berries have a rescuing effect. They seem to restore the normal housekeeping function. These findings are the first to show these effects of berries” (ACS 2010).
As the Tufts-USDA team noted in the new evidence review, we don't yet know whether these brain benefits flow from specific polyphenols, or from the roughly similar combinations of polyphenols seen across berry species.
Given the growing evidence that whole foods outperform single nutrients, we'd place our bet on the polyphenol blend delivered by whole berries … one in which flavanols feature prominently, and likely play the leading brain protecting/boosting role.
American Chemical Society (ACS). Eating berries may activate the brain's natural housekeeper for healthy aging. August 23, 2010. Accessed at http://portal.acs.org/portal/acs/corg/content
American Chemical Society (ACS). Strong scientific evidence that eating berries benefits the brain. March 7, 2012. Accessed at http://portal.acs.org/portal/acs/corg/content
Mertens-Talcott SU, Rios J, Jilma-Stohlawetz P, Pacheco-Palencia LA, Meibohm B, Talcott ST, Derendorf H. Pharmacokinetics of anthocyanins and antioxidant effects after the consumption of anthocyanin-rich acai juice and pulp (Euterpe oleracea Mart.) in human healthy volunteers. J Agric Food Chem. 2008 Sep 10;56(17):7796-802. Epub 2008 Aug 12.
Miller MG, Shukitt-Hale B. Berry Fruit Enhances Beneficial Signaling in the Brain. J Agric Food Chem. 2012 Feb 3. [Epub ahead of print]
Poulose SM, Fisher DR, Larson J, Bielinski DF, Rimando AM, Carey AN, Schauss AG, Shukitt-Hale B. Anthocyanin-rich Açai ( Euterpe oleracea Mart.) Fruit Pulp Fractions Attenuate Inflammatory Stress Signaling in Mouse Brain BV-2 Microglial Cells. J Agric Food Chem. 2012 Feb 1;60(4):1084-93. Epub 2012 Jan 20.
Shukitt-Hale B, Cheng V, Joseph JA. Effects of blackberries on motor and cognitive function in aged rats. Nutr Neurosci. 2009 Jun;12(3):135-40.
Shukitt-Hale B, Lau FC, Joseph JA. Berry fruit supplementation and the aging brain. J Agric Food Chem. 2008 Feb 13;56(3):636-41. Epub 2008 Jan 23. Review.
Willis LM, Shukitt-Hale B, Joseph JA. Recent advances in berry supplementation and age-related cognitive decline. Curr Opin Clin Nutr Metab Care. 2009 Jan;12(1):91-4. Review.