Fiber medicine

Not all dietary fiber is created equal: grains, but not fruit or vegetable fiber, help inflammation

Researchers from the Columbia University Mailman School of Public Health and their colleagues assessed whether dietary fiber intake was associated with decreased inflammation in older adults and whether fiber was inversely linked to cardiovascular disease. The results showed that total fiber, and more specifically grain fiber, but not fruit or vegetable fiber, was consistently associated with lower inflammation and lower CVD incidence. Until now, there has been little data on the link between fiber and inflammation in older adults, who have higher levels of inflammation than younger adults. The results of the study are published in Open JAMA Network.

The research includes data from a large, well-characterized prospective cohort of older adults, with detailed data on dietary intake, inflammation, and incidence of cardiovascular disease. The research confirmed previously observed associations between dietary fiber and CVD and extended these investigations to include the source of fiber, the relationship of fiber to several inflammatory markers, and to test whether inflammation was the cause of the relationship between dietary fiber and CVD.

Of the 4,125 adults enrolled in the Heart Health Study from 1989 to 1990, participants were given a food frequency questionnaire that was administered to people without prevalent cardiovascular disease at the time of enrollment and then completed the underwent follow-up visits for the development of cardiovascular disease (stroke, myocardial infarction and atherosclerotic cardiovascular death) until June 2015. Blood samples were evaluated for markers of inflammation.

“Higher dietary fiber intakes are associated with lower CVD risk. A common hypothesis is 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 the results of this study, we are now learning that a particular type of dietary fiber – grain fiber – but not fruit or vegetable fiber, was associated with lower inflammation. With the results of this study, we are now learning that cereal fiber has the potential to reduce inflammation and will need to be tested in future intervention studies.

Although there is some data to suggest that fiber in general may have anti-inflammatory effects by improving bowel function, altering diet and satiety (eg, fruit fiber is associated with lower inflammation n is unclear and warrants further investigation, Shivakoti noted.Furthermore, he notes that it is unclear whether grain fiber per se or other nutrients in high grain fiber foods are responsible. origin of the observed relationships.

“Additionally, we learned that inflammation had only a modest role in mediating the observed inverse association between cereal fiber and cardiovascular disease,” Shivakoti observed. “This suggests that factors other than inflammation may play a greater role in reducing cardiovascular disease associated with cereal fiber and should be tested in future interventions with specific populations.

The co-authors are from Columbia University Mailman School of Public Health; University of Washington; Brigham and Women’s Hospital; Harvard Medical School; health care for Boston veterans; Larner College of Medicine at the University of Vermont; San Francisco Veterans Health Care System; University of California-San Francisco; Kaiser Permanente Health Research Institute of Washington; 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.