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 July 8, 2003 - last reviewed on June 9, 2016
You probably know about the powerful antioxidant properties of
vitamins C, and E, and beta carotene. But there's another group of
antioxidants receiving a lot of attention; their names are less
pronounceable, but their health benefits are at least as powerful.
Quercitin, kaempferol, and epigallocatechin might never become
household words, but they are already household ingredients. They are
just three among over 4,000 compounds classified as flavonoids. 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.
They may play a special role in protecting the brain.
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.
Flavonoids are present in myriad fruits and veggies, common and
uncommon, but some sources are better than others. In general, the more
deeply-hued the plant, the more flavonoids it provides. Fortunately, you
don't have to eat brussels sprouts (they have a low flavonoid content) to
get your flavonoid fix. Some potent flavonoid sources may even be on
your favorite foods list. Good sources of various flavonoids
Quercetin is the flavonoid that enables
apples to keep the doctor away. Quercetin has been shown to reduce
cancer risk, prevent heart attacks, stave off cataracts, control asthma,
prevent recurrent gout attacks, and speed healing from acid
Green tea contains, among others, the
cancer-fighting flavonoid epigallocatechin gallate (ECGC). ECGC is unique
in that it seems to battle cancer at all stages, from thwarting chemical
carcinogens, to suppressing the spread of tumors. ECGC is as much as 100
times more powerful an antioxidant as vitamin C, and 25 times more
powerful than vitamin E. ECGC also may account for the antibacterial
properties of green tea.
Chocolate contains many of the same
flavonoids found in tea. The darker the chocolate, the more flavonoids
present. Cocoa powder is the richest source by weight, and to maximize
your benefits, make your hot chocolate from scratch. Homemade hot
chocolate will provide you with more flavonoids than a store-bought
Flavonoids are the source of the
well-known "French Paradox"—the ability of the French to consume lots of
fat-laden cheese without dropping like flies from heart attacks. The red
wine they enjoy is flavonoid-rich, which lowers their risk of
heart disease. And if you're not a drinker, you can get almost all the
same benefits from purple grape juice.
The pomegranate carries with it the
mystique of ancient myth, but we moderns are beginning to realize that
its health benefits are very real: pomegranate juice may have almost
three times the antioxidant potency of an equal volume of green tea or
Delicious, relaxing chamomile tea is
home to the flavonoid called apigenin, one of a handful of flavonoids
recently found to have mood-enhancing properties. Currently the focus of
intense study, they are thought to act on the same parts of the brain as
common anti-anxiety drugs. In fact, certain synthetic flavonoids have
been shown to have anxiolytic properties superior to diazepam. Research
is in its infancy, however. For now, take your apigenin with sugar and
While many health benefits of flavonoids are not in dispute, there
are a couple caveats to consider before sitting down to fill your face
First, scientists are only now beginning to understand the effects
of flavonoids in the body. As natural but real chemicals, flavonoids can
interact with prescription drugs in a harmful way. The flavonoid
naringenin found in grapefruit, for example, can interfere with the
breakdown of certain drugs, magnifying their potency. It's best not to
take any drugs with grapefruit juice unless the drug interaction profile
of the medication is well known.
Second, taking flavonoid supplements is not the way to go. UC
Davis' Dr. Mitchell cautions people not to think they can just take a
supplement instead of consuming more fruits and vegetables. Whole foods
supply the added benefits of vitamins, minerals and fiber.
Furthermore, the dosage furnished by supplements can vary widely
but is likely to be much higher than what you'd receive from a healthy,
balanced diet. Reseachers have yet to determine exactly what levels of
flavonoids are optimally beneficial, or even whether flavonoids become
harmful at very high doses. As with all supplements, flavonoid
supplements are not stringently regulated by the FDA.
"Much about flavonoids still remains to be discovered," observes
Dr. Mitchell, "and it's important not to view them as the latest fad
cure-all." Her advice echoes what your mother once told you: The most
positive thing you can do for your health is to eat more fruits and
If you're curious to learn about more whole food sources of
flavonoids, the USDA has an online database of 225 foods and their
flavonoid content. You can find it at