Flavonoids: Antioxidants Help the Mind
Naturally occurring plant pigments, flavonoids are one of the reasons fruits and vegetables are so good for you. Among the many benefits attributed to flavonoids are reduced risk of cancer, heart disease, asthma, and stroke.
By Erik Strand, published in 'Psychology Today ' on July 08, 2003
Flavonoids, like other antioxidants, do their work in the body by corralling cell-damaging free radicals and metallic ions. But flavonoids go beyond the yeoman work of your average antioxidant. Scientists have found that certain flavonoids have antihistamine, antimicrobial, memory- and even mood-enhancing properties.
Food scientist Alyson Mitchell, Ph.D., who studies flavonoids at UC Davis, is optimistic about the salutary power of these compounds: "The current hope of scientists is to discover exactly what flavonoids should be eaten in what amounts to fight specific diseases."
Scientists already have some proof that antioxidants protect against and even reverse the cognitive declines seen from aging. The brain is especially subject to attack from free radicals of oxygen, as it is extremely metabolically active and the body's largest consumer of oxygen. Yet, it is deficient in free radicals to start with. Cumulative damage from free radicals occurs across the board but is especially implicated in memory decline, slowing of body movements and the fatigue, irritability, and mood disturbance that mark depression.
But tea's rising favor may also be due to the soothing ritual of making a cup, according to Ron Rubin, "Minister of Tea" (or president, in layman's terms) at the Republic of Tea, a California-based company devoted to taking life "sip by sip, rather than gulp by gulp." The time it takes to steep tea leaves in hot water and savor its gentle flavor, which is kinder than that of coffee, forces drinkers to slow down and relax, he says, making it the perfect antidote to a caffeine-charged, cappuccino-crazy world.
Working in a country famous for its afternoon tea ritual, researchers at England's University of Newcastle upon Tyne have released a new study detailing how green and black tea can actually improve your memory. Dr. Ed Okello and his team have located compounds in the leaves of the Camellia sinensis plant, which produces green, black and oolong teas, that block the activity of brain chemicals that are associated with memory decline.
One such brain chemical is acetylcholinesterase (AChE), an enzyme that breaks down the neurotransmitter acetylcholine. Acetylcholine is involved in lots of activities in the brain and the rest of the body. For example, it triggers muscle contractions. In the central nervous system, it is involved in wakefulness, attentiveness, anger, aggression, sexuality, and thirst, among other things.
Alzheimer's disease is associated with a lack of acetylcholine in certain regions of the brain. But decreases in acetylcholine also occur in the aging process generally. That's the bad news.
The good news is that we may actually be able to boost our acetylcholine levels by simply heeding the advice of our British counterparts and drinking tea. The idea is simple enough: raising chemical levels in the brain improves communication among the various neurotransmitters (the brain's messenger system), which in turn improves general memory. What could be done with complicated, often expensive drugs may instead be accomplished with a simple dunk of a green tea bag.
Further, tea delivers a double whammy. It not only boosts levels of acetylcholine. It blocks another substance that is found in the protein deposits that gunk up the brains of people with Alzheimer's disease.
"We can all expect to experience slight memory loss as we age, like forgetting our grocery lists," explains gerontologist Bonnie Kantor of Ohio State University. "The goal is to work on ways to promote cognitive vitality so you never have to get to the stage of arriving at a grocery store and forgetting what one does there."
One way may be to reduce "oxidative stress" -- the damage done by free radicals of oxygen, destructive molecules given off by normal metabolic processes and by toxins. Here's where tea measures up once again. Compounds called flavonoids found in green and black teas appear to be effective antioxidants, especially helpful in countering brain damage done by free radicals.