Got flavonoids? Study shows how colorful fruits and veggies help preserve long-term brain health

by Craig Weatherby

Researchers in the US and Japan have published the results of a mouse study with implications for the benefits of Americans’ favorite berry (Maher P et al 2006).

As Lead author Pamela Maher, Ph.D. of the Salk Institute said, "…the holy grail of CNS [central nervous system] research in the pharmaceutical industry is the identification of a safe, orally active drug that activates memory-associated pathways and enhances memory."

And her team may have found a good candidate, if not the grail itself. The US-Japan team found that fisetin—a flavonoid-class polyphenol antioxidant found in strawberries and other fruits and vegetables—stimulates signaling pathways that enhance long-term memory.

Dr. Maher discovered the beneficial effects of fisetin earlier, while screening a number of flavonoids for their ability to protect brain cells in a test-tube experiment that simulated the effects of Alzheimer’s and other degenerative brain diseases.

She found that many flavonoids perform several key functions:

• Protect brain cells from dying
• Promote new connections between nerve cells
• Promotes memory formation.

The pan-Pacific team found that fisetin also stimulated key processes in the hippocampus: a part of the brain that plays a key role in creating and storing new memories.

(For any neuroscientists in the audience, fisetin activated the ERK signaling pathway, stimulated long-term potentiation, and induced phosphorylation of the cAMP response element-binding protein in hippocampal tissues from the rats.)

They also tested fisetin's ability to help mice remember different objects, and found that the animals given a dose of fisetin recalled objects more quickly and easily.

In fact, the extract improved their performance about as effectively as a new drug called rolipram, which enhances memory by making brain synapses more resistant to damage caused by accumulation of the beta-amyloid protein plaques characteristic of Alzheimer’s.

Fisetin is also found in tomatoes, onions, oranges, apples, peaches, grapes, kiwifruit and persimmons. (Interestingly, while the memory-enhancing supplements derived from the leaves of Gingko biloba trees are rich in other flavonoids, they do not contain fisetin.)

Fortunately, fisetin is not the only brain-benefiting flavonoid, since it would take about 10 pounds of strawberries a day to equal the dose given the mice!

Instead, the idea is to fill your diet with berries and a range of colorful, flavonoid-filled foods and beverages: a perfectly pleasurable prospect.

Sources

• Maher P, Akaishi T, Abe K. Flavonoid fisetin promotes ERK-dependent long-term potentiation and enhances memory. Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16568-73. Epub 2006 Oct 18.
• Bourtchuladze R, Frenguelli B, Blendy J, Cioffi D, Schutz G, Silva AJ. Deficient long-term memory in mice with a targeted mutation of the cAMP-responsive element-binding protein. Cell. 1994 Oct 7;79(1):59-68.