Leslie Capo, LSU Health New Orleans
Research led by Lauri Byerley, PhD,
RD, Research Associate Professor of Physiology at LSU Health New Orleans School
of Medicine, has found that walnuts in the diet change the makeup of bacteria
in the gut, which suggests a new way walnuts may contribute to better health.
The findings are published in The
Journal of Nutritional Biochemistry available online.
“Walnuts have been called a
‘superfood’ because they are rich in the omega-3 fatty acid, alpha-linolenic
acid and fiber, and they contain one of the highest concentrations of
antioxidants,” notes Dr. Byerley.
“Now, an additional superfood benefit of
walnuts may be their beneficial changes to the gut microbiota.”
Working in a rodent model, the research team added walnuts to the diet of one group. The diet of the other group contained no walnuts. They then measured the types and numbers of gut bacteria in the descending colon and compared the results.
They found that
there were two distinct communities of bacteria in the groups. In the
walnut-eating group, the numbers and types of bacteria changed, as did the
bacteria’s functional capacity. The researchers reported a significant increase
in beneficial bacteria like Lactobacillus.
“We found that walnuts in the diet
increased the diversity of bacteria in the gut, and other non-related studies
have associated less bacterial diversity with obesity and other diseases like
inflammatory bowel disease,” says Byerley.
“Walnuts increased several bacteria,
like Lactobacillus, typically associated with probiotics suggesting walnuts may
act as a prebiotic.”
Prebiotics are dietary substances
that selectively promote the numbers and activity of beneficial bacteria.
“Gut health is an emerging research
area, and researchers are finding that greater bacterial diversity may be associated
with better health outcomes,” adds Byerley.
The researchers conclude that the
reshaping of the gut microbe community by adding walnuts to the diet suggests a
new physiological mechanism to improve health.
Eating walnuts has been
associated with reduced cardiovascular disease risk, slower tumor growth in
animals and improved brain health.
The LSU Health New Orleans research
team also included Drs. Derrick Samuelson, Eugene Blanchard, IV, Meng Luo,
Sheila Banks, David Welsh, Brittany Lorenzen and Christopher Taylor, as well as
Dr. Monica Ponder at Virginia Tech.
The research was supported by the
American Institute for Cancer Research and California Walnut Commission.