A new study suggests eating a meal of seafood or other foods containing omega-3 fatty acids
at least once a week may protect against age-related memory loss and thinking
problems in older people. Researchers from Rush University Medical Center
and Wageningen University in the Netherlands discovered study participants who
reported eating seafood less than once a week experienced more rapid memory
decline than those who ate at least one seafood meal per week.
The study helps to show that
while cognitive abilities naturally decline as part of the normal aging
process, there is something that we can do to mitigate this process,” says Martha Clare Morris, ScD, a
Rush nutritional epidemiologist and senior author of the paper.
The research findings appear online in Neurology,
the medical journal of the American Academy of Neurology. For the
investigation, researchers followed 915 people with a mean age of 81.4 years
for an average of five years. At study enrollment, none had signs of dementia. Participants were recruited from people already
taking part in the Rush Memory and Aging Project, a study of residents of more
than 40 retirement communities and senior public housing units across northern
Illinois, plus older adults identified through church groups and social service
agencies.
During the course of the study, each person
received annual, standardized testing for cognitive ability in five areas.
Domains tested included episodic memory, working memory, semantic memory,
visuospatial ability and perceptual speed. The study group also completed
annual food frequency questionnaires, allowing the researchers to compare
participants’ reported seafood intake with changes in their cognitive abilities
as measured by the tests.
The questionnaires included four types of seafood:
tuna sandwiches; fish sticks, fish cakes and fish sandwiches; fresh fish as a
main dish; and shrimp, lobster and crab. The participants were divided into two
groups: those who ate at least one of those seafood meals per week and those
who ate less than one of those seafood meals per week.
Participants in the higher seafood consumption
group ate an average of two seafood meals per week. Those in the lower group
ate an average of 0.5 meals per week. Seafood is the direct nutrient source of
a type of omega-3 fatty acid (docosahexaenoic acid) that is the main structural
component of the brain. While epidemiologic studies have shown the importance
of seafood and omega-3 fatty acids in preventing dementia, few prior studies
have examined their associations with specific types of cognitive ability.
In the new study, the researchers report links or
associations between seafood consumption and two of the areas of cognitive
ability. Specifically, people who ate more seafood had reduced rates of decline
in the semantic memory, which is memory of verbal information. They also had
slower rates of decline in a test of perceptual speed, or the ability to
quickly compare letters, objects and patterns. The study did not find a significant difference in
the rate of decline in episodic memory (recollection of personal experiences),
working memory (short-term memory used in mental function in the immediate
present) and visuospatial ability (comprehension of relationships between
objects).
The relationships held even when researchers
adjusted for other factors that could affect memory and thinking skills, such
as education, physical activity, smoking and participating in mentally
stimulating activities.
Further, the
protective association of seafood was even stronger among individuals with a
common genotype (APOE-ε4) that increases the risk of developing Alzheimer’s
disease. The APOE is a gene involved in cholesterol transport
to neurons. About 20 percent of the population carries the APOE-ε4 gene,
although not everyone who has the gene will develop Alzheimer’s disease.
Article courtesy of Rick Nauert PhD , psych central news
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