In addition, researchers also found that people in the study generally consumed lower amounts of fiber than is recommended by the Institute of Medicine.
"Our findings indicate that, among a nationally representative sample of nonpregnant U.S. adults in NHANES [National Health and Nutrition Examination Survey] 1999-2010, the consumption of dietary fiber was consistently below the recommended total adequate intake levels across survey years," study researcher Cheryl R. Clark, M.D., Sc.D., of the Center for Community Health and Health Equity, Brigham and Women's Hospital and Harvard Medical School, said in a statement.
Women ages 19-50 should get 25g of fiber each day, while men in the same age group should get 38g, according to guidelines from the Institute of Medicine. And women older than 50 should get 21g of fiber each day and men older than 50 should get 30g.
However, the study, published in the American Journal of Medicine, showed that average dietary fiber intake was 16.2g each day, for all age groups and genders.