American Academy of
Neurology (AAN)
A new study shows that
older people who followed a Mediterranean diet retained more brain volume over
a three-year period than those who did not follow the diet as closely.
The
study is published in the January 4, 2017, online issue of Neurology®,
the medical journal of the American Academy of Neurology.
But contrary to
earlier studies, eating more fish and less meat was not related to changes in
the brain.
The Mediterranean diet
includes large amounts of fruits, vegetables, olive oil, beans and cereal
grains such as wheat and rice, moderate amounts of fish, dairy and wine, and
limited red meat and poultry.
"As we age, the brain shrinks and we lose brain cells which can affect learning and memory," said study author Michelle Luciano, PhD, of the University of Edinburgh in Scotland. "This study adds to the body of evidence that suggests the Mediterranean diet has a positive impact on brain health."
Researchers gathered
information on the eating habits of 967 Scottish people around age 70 who did
not have dementia.
Of those people, 562 had an MRI brain scan around age 73 to
measure overall brain volume, gray matter volume and thickness of the cortex,
which is the outer layer of the brain.
From that group, 401 people then
returned for a second MRI at age 76. These measurements were compared to how
closely participants followed the Mediterranean diet.
The participants
varied in how closely their dietary habits followed the Mediterranean diet
principles.
People who didn't follow as closely to the Mediterranean diet were
more likely to have a higher loss of total brain volume over the three years
than people who followed the diet more closely.
The difference in diet
explained 0.5 percent of the variation in total brain volume, an effect that
was half the size of that due to normal aging.
The results were the
same when researchers adjusted for other factors that could affect brain
volume, such as age, education and having diabetes or high blood pressure.
There was no
relationship between grey matter volume or cortical thickness and the
Mediterranean diet.
The researchers also
found that fish and meat consumption were not related to brain changes, which
is contrary to earlier studies.
"It's possible
that other components of the Mediterranean diet are responsible for this
relationship, or that it's due to all of the components in combination,"
Luciano said.
Luciano noted that
earlier studies looked at brain measurements at one point in time, whereas the
current study followed people over time.
"In our study,
eating habits were measured before brain volume was, which suggests that the
diet may be able to provide long-term protection to the brain," said
Luciano. "Still, larger studies are needed to confirm these results."
