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growing brain cells when you
DON'T FEED YOUR HEAD
by
MICHAEL ANFT
______________________________________________
During
his 25 years as a journalist, he has covered nonprofit
organizations nationwide for The Chronicle of Philanthropy,
delved into media and political matters and the arts for
Baltimore's City Paper, written about pop music
for The Baltimore Evening Sun, and penned stories
on business for Warfield's. He has also reviewed books
for The Washington Post. He is the senior writer
at John Hopkins
Magazine where this article originally was published.
Fish, we're
told, is brain food. So are blueberries, as they contain
nutrients that help us remember things. But could it be
that the brain, the hoggish human command center that makes
up only 2 percent of our total body weight but requires
20 percent of the calories we consume, is actually better
off when we deprive ourselves of food altogether?
Scientists at
the National Institute on Aging, led by Mark Mattson, a
professor of neuroscience at the School of Medicine, think
so. In several papers Mattson discussed during a meeting
of the American Association for the Advancement of Science
in February, he and other researchers say that depriving
ourselves via fasting twice a week could significantly lower
the risk of developing Alzheimer's disease or Parkinson's.
The findings
resonate with decades-old studies that show a link between
caloric intake and oxidative rusting -- the stress on cells
that comes when people get older and take in food. "One
of the only ways to slow down the progression of aging that
involves disease or organ malfunctions is to reduce energy
intake," says Mattson, who has been studying Alzheimer's
and the brain for 20 years and, according to Thomson Reuters'
database, is the most cited neuroscientist in scholarly
journals worldwide. "As is similar to what happens
when muscles are exercised, the neurons in the brain benefit
from being mildly stressed. To achieve the right kind of
stress, people might benefit from severely minimizing their
food intake."
Mattson and
others have tested their theories on animal models and small
groups of human subjects. In studies involving experimental
mice, neurons in the brain become more active when the rodents
are hungrily searching for food. What's more, fasting animals
develop protective measures against damage from stroke and
other mechanisms that cause degeneration in the brain. "What
we've discovered in both animal and human studies is that
it's good to submit your brain to challenges, especially
in the short term," Mattson says, citing research done
by several groups in recent years.
But why fasting?
Wouldn't reducing calorie intake overall also help the brain?
Apparently not, or at least not as much. Sticking to an
intermittent crash diet, with no more than 500 calories
two days per week, primes the brain for protection, he says.
Studies show that keeping calories at around that level
stimulates two messaging chemicals that operate at the cellular
level and are key to the growth of brain cells in animals
and humans, Mattson explains. The shock of fasting leads
the brain to create new cells. As neurons are coaxed to
grow, the brain becomes more resistant to the effects of
protein plaques that underlie cases of Alzheimer's, or the
damage inflicted by Parkinson's.
"Fasting
imposes more stress on the cells, but in a good way,"
he adds. "There's an increase in adaptive stress responses
when people intermittently fast that is good for maintaining
the brain."
Dietary changes
have long been known to have an effect on the brain. Children
who suffer from epileptic seizures have fewer of them when
placed on caloric restriction or fasts. It is believed that
fasting helps kick-start protective measures that help counteract
the overexcited signals that epileptic brains often exhibit.
(Some children with epilepsy have also benefited from a
specific high-fat, low-carbohydrate diet). Normal brains,
when overfed, can experience another kind of uncontrolled
excitation, impairing the brain's function, Mattson and
another researcher reported in January in the journal Nature
Reviews Neuroscience.
The intermittent
fasting advocated by Mattson and others for overall brain
health may be linked to how humankind has evolved. There
are reasons why the intermittent shocks of hunger do a brain
good. "Our ancestors undoubtedly had to go without
food for stretches of time," Mattson explains. "It
hasn't been that long since humanity lacked regular supplies
of food. When you search for food when you're hungry, the
brain is really engaged. The individuals who survive the
best -- the ones whose brains are more attuned to predators
and who can remember where food sources are -- are the ones
who've survived."
Partly because he is worried people might not be able to stick
to it, Mattson isn't promoting a strict, water-only fast.
He advises people to drink plenty of water or unsweetened
tea and to eat no more than 500 calories per fasting day via
fiber-rich vegetables. He warns, however, that fasting is
not recommended for the very young, who need many more calories
to keep them growing, or people over 70, whose brains seem
to derive little benefit from intermittent food deprivation.
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Arts
& Opinion, a bi-monthly, is archived in the
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ISSN 1718-2034
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