Brain
Viagra: Part 2 - There’s a huge market for substances
that claim to boost memory, but when can we expect drugs designed
and proven to do that? (4/21/03)
Placebo
Effect - Neuroscientists say finding the answer to why the
placebo effect works could help make real medicine more effective.
(4/15/03)
Bloody
Teeth Boost Memory - A memory researcher says we can manipulate
emotion to help improve our memory. (2/19/03)
Elsewhere on the web
An
Herb for Alzheimer’s?
Ginkgo
Biloba Clinical Trials
JAMA
Study: Gingko doesn’t improve memory
JAMA
Study: Ginkgo helped some Alzheimer's patients
Companies selling the herbal supplement gingko biloba say it can enhance your
memory.
But as this ScienCentral News video reports, scientific evidence on whether
gingko works has been controversial at best.
Natural Memory Boost?
Improve your memory by taking something found in nature! And you don’t
need a prescription! Is it too good to be true?
Gingko biloba, extracted from the leaves of the
gingko
tree and available in health food stores, supermarkets and countless internet
sitesis one of the most widely used herbal treatments for improving memory,
and people in the U.S. spend millions of dollars on it every year. The scientific
community has taken note; the National
Institute on Aging is currently supporting a clinical
trial to evaluate the efficacy of gingko in treating the symptoms of Alzheimer’s
disease.
“Gingko has become a very popular [supplement], partly because there
is a sort of pent-up demand for something that will enhance memory and cognitive
function,” says Steven
Ferris of the Institute
for Aging & Dementia at NYU Medical School. Sometimes the supplement
is even marketed as a kind of “Brain Viagra,” with
claims
that it increases circulation in the brain and protects it from tissue-damaging
substances. The American Herbal
Products Association (AHPA) cites a review article in a British Journal
that found “promising evidence of improvement in cognition with gingko.”
But not all scientists are convinced. An article
in the April 2003 issue of Scientific American reviewed more than forty
studies on gingko, and came to the conclusion that, “in general, the
reported effects are rather small.” Paul
Gold, a psychology professor at the University of Illinois at Urbana-Champaign
and one of the authors of the article, says, “The information available
is so uninformed that it’s difficult to imagine that a consumer would
have a good reason to use gingko.”
“There’s been a fair number of studies testing gingko in various
populations of patients and ordinary people to see if it improves cognition,”
explains Ferris. “The main problem is that almost all of those studies
were very poorly designed and really don’t properly address the questions
of whether it really works or not in a scientifically valid way.”
For example, gingko researchers typically test their subjects with learning
and memory tests after they have used the supplement for several months, making
it hard to identify which brain functions have been affected. In order to
get more specific data on gingko’s effects, researchers would have to
test their subjects both before and after they take the supplement.
Also, for drugs manufactured by pharmaceutical companies, researchers typically
conduct studies with lab animals before they test on humans. But the Food
and Drug Administration doesn’t consider gingko a drug, so it is only
regulated as a dietary supplement (a special category of food). The Scientific
American article says that as a result, its manufacturers have not been
required to test animals first. But Steven
Dentali, VP of science at the AHPA, says the real reason is “a lack
of economic incentive, because ginkgo is a natural product and largely unbranded.”
Cheap and easy memory boosters
“While there is essentially little if any evidence supporting the claim
that gingko actually improves memory in human beings, there are many other
things, very common substances and very common events in peoples’ lives,
that actually enhance our ability to remember,” says Ferris.
Light exercise, even just squeezing
something like a stress ball, can elevate the levels of certain chemicals
in your brain that are important to memory formation. So can having an emotional
experience, both positive and negative. For instance, hearing an exciting
story can release a neurotransmitter called epinephrine into one’s circulation,
which enhances memory without any drugs. In both cases, moderation is the
key, as too much exercise or emotion can actually inhibit memory.
Furthermore, if your blood sugar is low there is something you can buy at the
supermarket that might tweak your memory a bit--candy. “There is actually
good evidence that having a candy bar or just having a sweet drink with sugar
in it improves your ability to remember if your blood sugar levels are low,”
says Ferris. He points out that studies
have shown that people who got a drink with glucose in it performed better
on a memory test than those who got a placebo. (He also points out that this
needs to be considered in moderation as well: “People shouldn’t
be filling up on sugar thinking it’s going to help their memory,”
adding that this has its biggest effect when blood sugar levels are low.)
Still, memory loss is a real problem, especially among the elderly, and many
people are in need of a solution. “There are millions of older people
who have experienced a very real decline in their memory ability,” says
Ferris. “If there were such a pill and it were approved by the FDA for
improving memory, I, along with millions of other people, would probably try
it.”