The Mediterranean Diet & Cognition
The Mediterranean Diet & Cognition
Memory loss often is
indicative of the normal aging process, but it also may be a sign of
neurodegenerative disease development, namely Alzheimer’s disease, a form of
dementia that Causes problems with memory,
behavior, and thinking, and gradually worsens over time. While there’s no known
cure for Alzheimer’s, research suggests that a healthful lifestyle that includes
following a Mediterranean pattern of eating and regular physical activity may
delay or slow The disease’s progression.
An estimated 5.2
million Americans of all ages have Alzheimer’s, including 5 million people aged
65 and older as well as approximately 200,000 who have younger-onset
Alzheimer’s. Experts believe that number will increase to 7.1 million by 2025
and nearly triple by 2050.
“Alzheimer’s is caused
by the accumulation of two chemicals in the brain: amyloid and tau,” explains Nikolaos
Scarmeas, MD, MSc, an associate professor of neurology at Columbia University
Medical Center. “Why they accumulate in abundance is not known, but they
Negatively affect
brain cells that eventually die. Due to the loss of brain cells, the patients
with this disease experience cognitive decline. The decline starts from memory
because the brain cells responsible for memory are affected first, but involves
gradually, over the course of about a decade, the decline of all higher cognitive
functions.”
Alzheimer’s is the
most frequent type of dementia, adds Miguel A. MartÃnez-González, MD,
PhD, MPH, chair of
the department of preventive medicine and public health in the medical school at
the University of Navarra in Spain. In addition to memory, it impairs the
ability to perform activities of daily living and is characterized by a
progressive
Chronic impairment,
he says.
The disease can be
devastating to patients and their families. Although the reasons aren’t fully
Understood, there
does seem to be a link between a healthful lifestyle and a decrease in cognitive
impairment. Recent research has focused more specifically on the positive
benefits of the Mediterranean diet and the reduced risk of Alzheimer’s as well
as other cognitive functions. ➸
A Mediterranean diet essentially is a
plant-based diet that’s characterized by consuming a variety of fresh fruits and
vegetables, grains, and plenty of fish. “Modest amounts of olive oil use
instead of butter, and you basically use food to flavor food, such as basil,
garlic, and onions,”
Adds Joan Salge Blake, MS, RD, LDN, a
nutrition educator and clinical associate professor at Boston University and a
national spokesperson for the Academy of Nutrition and Dietetics (the Academy).
“It focuses on using seasonal foods, so it’s a fresh and tasty diet. Meat and
sweets are consumed in very small portions, and it’s about making fruits and vegetables
the main focus of the plate.”
Past research has indicated that this
diet, high in fruits, vegetables, and unsaturated fatty acids, has been
associated with slowing and even preventing the metabolic syndrome, protecting
the kidneys, and reducing the risk of other chronic diseases such as heart
disease and diabetes and, more specifically, neurodegenerative disease. For
example, a metaanalysis published in the October 2013 issue of Annals of Neurology
showed that high adherence to a healthful dietary pattern, such as the
Mediterranean diet, may be beneficial in the prevention of various conditions
linked to the aging brain, including cognitive decline, depression, and stroke.
The research team behind the meta-analysis, led by Theodora Psaltopoulou, PhD,
of the University of Athens School of Medicine in Greece, found that a
Mediterranean diet was protective for both of the student subgroups,
participants who had mild cognitive decline and those who had advanced
cognitive decline, and showed positive effects when looking specifically at
Alzheimer’s. Another meta-analysis, published in the July 2013 issue of Epidemiology,
also found that greater adherence to a Mediterranean diet was associated with
slower cognitive decline and a lower risk of developing Alzheimer’s. The researchers
of this meta-analysis suggested that further studies are warranted to clarify a
possible association between diet and mild cognitive impairment or vascular
dementia, along with long-term randomized controlled trials looking more
closely at the possibility of preventing or delaying the onset of Alzheimer’s.
Moreover, according to recent research
presented at the Society for Neuroscience meeting in November 2013, there was a
significant association with a slow decline in executive function (e.g., the
ability to remember details, switch focus, manage time and attention) at three
years’ follow-up among subjects who adhered to a Mediterranean diet. Those who adhered
to a Western diet (rich in red meat, processed foods, refined grains, potatoes,
and fatty dairy foods) had a significantly increased risk of declines in
visuospatial functioning, the ability to process and interpret visual
information about where objects are in space, at three years’ follow-up.
While there’s research suggesting there
are many positive benefits associated with following a Mediterranean diet, the reason
why this diet may lead to better brain health remains uncertain, although many theories
exist. Researchers and dietitians tend to agree that consuming a diet that’s
primarily plant based, focused on real and whole foods, and devoid of processed
foods and red meat has much to do with its positive effects on cognitive
health.
Weighing
in on the Research
Proponents of the Mediterranean diet
tend to single out the health benefits of olive oil and focus on the omega-3 fatty
acids. However, some believe the cognitive benefits may result more from a
synergistic combination of all the healthful foods that make up the diet. “It
might be the omegas, the antioxidants, the flavonols, and the large number of
vitamins all working together to have the positive benefit of reducing cognitive
impairment,” says Kathy McManus, MS, RD, LDN, director of the nutrition
department at Brigham and Women’s Hospital in Boston. “Or it may just be the
fact that those who consume a Mediterranean diet tend to be healthier
individuals in the first place.”
Marjorie Nolan Cohn, MS, RD, CDN,
ACSM-HFS, a national spokesperson for the Academy, agrees: “When you look at
the
Research, there are many variables that
can’t be counted. These are correlational studies that report on what people
ate 20 years ago. The fact is that those who followed a Mediterranean-like diet,
probably have other healthful habits too, which complicates it even more since
other factors, such as physical activity, also may have had a role in
preventing Alzheimer’s. But what can’t
be discounted is the fact that this is an all-around very healthful diet and
regardless of whether you can pinpoint the exact healthful effects it may have,
it still makes sense to adopt it.”
While focus often is placed on the foods
eaten in any given date, Sharon Palmer, RD,
Author of The Plant-Powered Diet,
adds that with the Mediterranean diet, it may be as
Much about what’s not eaten that makes this
diet so beneficial. “In a traditional Mediterranean diet, you’re avoiding high amounts
of meat, refined carbs, and highly processed foods, and in their place you’re filling
up with all the good stuff: minimally processed grains, lots of seasonal and local
fruits and vegetables, legumes, olive oil, nuts, and seeds,” she explains. “You’re
limiting your saturated fats, high-glycemic carbs, sodium, and cholesterol
because
You’re not eating a lot of meat and
highly processed food. The Mediterranean diet originated from one that was
locally available in poor countries. They ate things that surrounded them, and there
was no room for industrial, imported foods. It was the ‘poor man’s death’ in
which people made something of nothing—foraging foods, fishing the oceans, and
growing their own produce.”
In addition, research on the brain has
indicated that chronic inflammation is a factor in Alzheimer’s development, and
therefore the anti-inflammatory effects of the Mediterranean diet are surmised
to be a possible reason behind the improved cognitive function. “Some components
present in fruits, vegetables, nuts, red wine, and virgin olive oil are able to
exert potent anti-inflammatory effects,” MartÃnez-González says.
Incorporating
the Mediterranean Diet
While the Mediterranean diet has
received much attention recently, clients still may not know what it is or how
to incorporate it into their daily lives. “One of the things that always
surprises me is how often people say they don’t know what it is,”
McManus says. “As dietitians, we hear so
much about it, but my patients often say they’ve never heard of it, and even if
they have, they don’t really understand what it is. So the first step is
educating people about what a Mediterranean diet menus.
The keys are that its plant based, it
involves whole foods, and it involves real food. I give my patients a copy of
the [Mediterranean diet] pyramid, which they find helpful. Oldways [which
created the pyramid] also is an excellent source for information.”
The big thing is helping people translate
the diet into their own daily lives, Palmer says. “I think a lot of people
think of the diet as just using olive oil on everything, but olive oil is just
one facet of the diet. At its core, the diet focuses on whole, locally available,
seasonal plant foods; healthful fats; and fish as the primary animal protein.
So you can take that concept and apply it to a diet in the Midwest, Northwest,
or South by asking: what are the locally available whole plant foods in this
region? And what fish are available? People need help translating diet patterns
to their region.”
Adherence to the diet also means
applying it to particular culinary traditions within a person’s lifestyle,
Palmer continues:
“For example, if you have Scandinavian
heritage, you can apply the Mediterranean diet strategy to your own favorite
food traditions by eating whole grain rye bread, enjoying traditional fish dishes,
and enjoying favorite vegetable dishes such as those based on beets, cabbage,
and carrots.”
Ask your clients and patients begin to
adopt the practices of the Mediterranean diet, they may find it’s easier to do than
they once thought. To help them make a commitment, Nolan Cohn tells patients to
choose two days each week for fish dinners and stick with them. Because fish don’t have as long a shelf life like other protein products, she suggests that “fish
net” be
Within a day or two of grocery shopping.
While the Mediterranean diet is focused
on fish as a main protein source, Nolan Cohn says those who have trouble giving
up red meat may be pleased to know that grass-fed lean beef,
Though often much more expensive than
non–grass-fed beef, is high in omega-3 fatty acids and low in fat.
“Contradictory to what people have heard for so long about the Mediterranean
diet, this is a way that you’re able to
make a compromise and get that beef, which can be hard for some to give up,”
she says.
“It’s more costly, so it might be once a
week or a special treat, but many patients appreciate learning it’s not
something they have to completely avoid.”
Produce also can be expensive, but for
those who are concerned about the cost, Salge Blake says that buying what’s in season
will be most cost-effective and tastier, too. “I try to
Convey how easy it is to cook in the
Mediterranean diet,” she notes. “Roasting vegetables is wonderful, and it’s
easy. All you need is a little bit of olive oil and some herbs and spices.
You can try any combination: shallots
and onions with savory chunks of squash, broccoli and garlic, or whatever it is
you prefer. The next day the vegetables are evenly delicious cold or
Tossed in with a salad.”
Salge Blake says offering patients
recipes are one of the best ways to set them up for success. And research seems
to indicate that an educated patient is a successful one. MartÃnez-González
says that after 61⁄2 years of follow-up with more than 500 patients in the PREDIMED-NAVARRA
randomized trial, the groups who were educated about the Mediterranean diet had
significantly better cognitive abilities than those who didn’t
Receive the education. The bottom line
is that one reason the Mediterranean diet
Has such health potential is that it’s
delicious and easy, and it sets people up for success, according to Palmer:
“The diet has evolved over thousands of years in this region of the world. It’s
not at all about deprivation. You can have a good percentage of healthful
fat—olive oil, avocados, and nuts—which makes everything taste great. And the
foods have lots of flavor; they’re fresh and local. Plus, it even includes
moderate wine [consumption].
It’s about a lifestyle, not a diet. If
you go to the Mediterranean, you’ll observe that people don’t think of their
eating style as a diet, it’s just the way they live—and they love it.”
All Fitness __ The Mediterranean Diet & Cognition
By Lindsey Getz is a freelance
writer based
In Royersford, Pennsylvania.
No comments