Cereal fiber but not fruit or vegetable fibers are linked with lower inflammation
Columbia University's Mailman School of Public Health
Researchers at Columbia University Mailman School of Public Health and colleagues evaluated whether dietary fiber intake was associated with a decrease in inflammation in older adults and if fiber was inversely related to cardiovascular disease.
The
results showed that total fiber, and more specifically cereal fiber but not
fruit or vegetable fiber, was consistently associated with lower inflammation
and lower CVD incidence. Until now there had been limited data on the link
between fiber and inflammation among older adults, who have higher levels of
inflammation compared with younger adults. The study findings are published
in JAMA Network Open.
The research includes data from a large and well-characterized prospective cohort of elderly individuals, with detailed data on dietary intake, inflammation, and incidence of CVD.
The research confirmed previously observed associations
between dietary fiber and CVD and extended those investigations to include the
source of the fiber, the relationship of fiber with multiple inflammatory
markers, and to test whether inflammation mediated the relationship between
dietary fiber and CVD.
Of
the 4125 adults enrolled in the Cardiovascular Health Study from 1989 to 1990
participants received a food frequency questionnaire that was administered to
those without prevalent CVD at enrollment and then were followed up visits for
development CVD (stroke, myocardial infarction, and atherosclerotic
cardiovascular death) through June 2015. Blood samples were assessed for
markers of inflammation.
"Higher intakes of dietary fiber is associated with lower CVD risk. A common hypothesis has been that higher fiber intakes reduce inflammation, subsequently leading to lower CVD risk" said Rupak Shivakoti, PhD, assistant professor of epidemiology at Columbia Mailman School.
'With findings from this study, we are
now learning that one particular type of dietary fiber -- cereal fiber -- but
not fruit or vegetable fiber was associated with lower inflammation. With
findings from this study we now are learning that cereal fiber has the
potential to reduce inflammation and will need to be tested in future
interventional studies."
Although there are data to suggest that fiber in general might have anti-inflammatory effects by improving gut function, modifying diet and satiety (eg, reduced fat and total energy intake), and improving lipid and glucose profile metabolism, why cereal fiber but not vegetable or fruit fiber is associated with lower inflammation is not clear and warrants further investigation, noted Shivakoti.
Further, he notes that it is not clear whether cereal fiber per se or other
nutrients in foods rich in cereal fiber are driving the observed relationships.
"Additionally,
we learned that inflammation had only a modest role in mediating the observed
inverse association between cereal fiber and CVD," observed Shivakoti.
"This suggests that factors other than inflammation may play a larger role
in the cereal fiber-associated reduction in CVD and will need to be tested in
future interventions of specific populations.
Co-authors
are from Columbia University Mailman School of Public Health; University of
Washington; Brigham and Women's Hospital; Harvard Medical School; Boston
Veterans Healthcare; Larner College of Medicine at the University of Vermont;
San Francisco Veterans Affairs Health Care System; University of California-San
Francisco; Kaiser Permanente Washington Health Research Institute; New York
Academy of Medicine; Beth Israel Deaconess Medical Center; and Harvard Chan
School of Public Health,
The
research was supported by the National Heart, Lung, and Blood Institute, the
National Institute of Neurological Disorders and Stroke, and the Eunice Kennedy
Shriver National Institute of Child Health and Human Development.