Evidence mapping to assess the available research on fiber, whole grains, and health

Abstract

Evidence mapping is a useful methodology for characterizing existing research on a broad topic and identifying gaps in the scientific literature. Evidence mapping entails conducting a systematic literature search and extracting information on study details, often in the form of a database. Researchers at Tufts University and the North American branch of the International Life Sciences Institute created the Diet-Related Fibers & Human Health Outcomes Database, which is publicly available and updated annually. The database captures intervention studies examining dietary fiber and 10 predefined physiological health outcomes, including weight/adiposity, blood pressure, gut microbiota, and bone health. The database and subsequent potential for evidence mapping may be particularly useful in light of new food labeling requirements by the US Food and Drug Administration that require fibers to have accepted scientific evidence of a physiological health benefit in order to be labeled as "dietary fiber." Following the success of the fiber database, Tufts University and the General Mills Bell Institute of Health and Nutrition collaborated to develop a whole grain database and evidence map. This work successfully highlighted the need for better consistency in how whole grains are reported with respect to amount and type of whole grains and intervention compliance.

Keywords: dietary fiber; evidence mapping; whole grains.

Figure 1

(a) Weighted scatter plot of other health outcomes captured within interventions examining type or source of dietary fiber and microbiota-related outcomes. (b) Weighted scatter plot of microbiota outcomes by type or source of dietary fiber intake. Abbreviations: GI, gastointestinal; SCFA, short-chain fatty acid; NSP, non-starch polysaccharide.

Figure 2

Weighted scatter plot of published studies on whole grain interventions and outcome categories examined. Abbreviations: GI, gastrointestinal; WG, whole grain.