The Cognitive Benefits of Walnuts
You've
likely heard that walnuts are good for the brain, but what exactly does
that mean, and do we have any proof of the nut having a beneficial
effect on cognition? In this article, we’ll explain the latest
scientific findings regarding walnut consumption and help you understand
whether or not you should count on walnuts improving your brain health.
Linking Walnuts and Brain Health
Walnuts are certainly among the healthiest varieties of nuts ,
having impressive heart health benefits and the ability to lower
cholesterol and inflammation levels in the body, both of which are known
to be good for brain health as well. The nuts are also packed with
healthy plant fats, such as omega-3 fats and alpha-linoleic acids, known
to benefit memory and cognition, which made researchers question
whether daily walnut consumption could have a beneficial effect on
cognition.
Since the early 2000s, test tube and animal studies have been conducted that strengthened the connection, with a 2014 study in
mice with simulated Alzheimer's disease even establishing that a walnut
rich diet can improve memory, learning, and even reduce anxiety levels
in the mice with AD.
The first human study regarding
the cognitive benefits of walnuts appeared in 2009, and it partly
confirmed the hypothesis that walnuts benefit cognition. In the study,
64 college students were recruited and their memory, reasoning, and mood
were measured over the course of 8 weeks, during which the participants
were divided into 2 groups that were interchangeably given a daily
portion of walnuts or a walnut-free diet.
As
you can probably tell, the study was quite small and the period during
which participants were followed was also short, but even in such as
short time and limited sample size, a diet containing walnuts proved
effective at improving the participants’ reasoning skills, which
prompted new research in the field, with a very compelling and credible
recent study finding a surprising link between walnuts and cognitive
decline.
Can Walnuts Slow Down Cognitive Decline in Seniors?
The largest study
to date investigating the cognitive benefits of walnuts in senior
populations was conducted in California and Spain and was recently
published in The American Journal of Clinical Nutrition. Known as The
Walnuts and Healthy Aging Study, the study looked at the health effects
of daily walnut consumption in 708 elders past the age of 60 in Loma
Linda, California, United States, and in Barcelona, Catalonia, Spain.
For
2 years, half of the participants ate a fixed portion of walnuts every
day, while the other half abstained from these nuts completely. After
that period, the participants' memory was accessed, and a
subsequent fMRI brain scan was conducted to check whether any reduction
in cognitive decline was observed in the participants that showed the
most improvement.
In
healthy individuals who were at a lower risk of cognitive decline,
researchers didn't observe any changes in memory performance, but
the subgroup that was at a higher risk of cognitive problems, e.g.
smokers, a diet rich in walnuts alone managed to slow down the
progression of cognitive decline. Though these results may not seem
stellar, they are still quite impressive, as the addition of just one
food managed to reduce the progression of disease in the group that
requires the extra boost the most.
The bottom line is
that walnuts seem to benefit brain health, but at present, we can't
reliably say if they have any cognitive boost for people who are healthy
overall, at least not in the short term. At the same time, we think
that you still add them to your diet for other reasons, such as
cardiovascular and digestive health. If you are at a higher risk of
cognitive decline, however, adding walnuts into your diet can also help
your brain retain its cognitive capabilities for longer.