Evidence mapping: dietary fiber interventions and bone health outcomes

Authors: RANCANO, KATHERINE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; HASLAM, DANIELLE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; SAWICKI, CALEIGH - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; STAFFIER, KARA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; SAHNI, SHIVANI - Harvard Medical School; CHUNG, MEI - Tufts University; MCKEOWN, NICOLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2017
Publication Date: 4/1/2017
Citation: Rancano, K., Haslam, D., Sawicki, C., Staffier, K.L., Sahni, S., Chung, M., Mckeown, N.M. 2017. Evidence mapping: dietary fiber interventions and bone health outcomes [abstract]. Federation of American Societies for Experimental Biology Conference. 31(1):645.5.

Interpretive Summary:

Technical Abstract: The prevalence of osteoporosis and low bone mass is expected to increase as the United States population ages. High dietary fiber intake has previously been implicated as a risk factor for bone health by binding calcium and thereby reducing its intestinal absorption; however, more recently, interventions with specific dietary fiber types have shown the opposite effect. The purpose of this study was to utilize evidence mapping to summarize the current body of literature investigating the effects of dietary fiber on bone health outcomes. We conducted a systematic search in Ovid MEDLINE, aimed at capturing intervention studies examining dietary fiber and bone health from 1946 to May 2016. The search identified 671 initial studies. A priori defined inclusion and exclusion criteria were then applied, which yielded 29 dietary intervention studies for inclusion in the final analyses. Descriptive statistics were used to summarize study design and population characteristics, dietary fiber types, and bone health outcomes. A bubble plot weighted by sample size was utilized to illustrate gaps in the literature. The majority of the studies were crossover, randomized, controlled trials (55.2%), had a sample size less than 25 (72.4%), and were conducted in North America (58.6%). The study populations were predominantly healthy (65.5%) adults (72.4%) (mean age age 33 years and BMI, 22 kg/m2). We classified dietary fibers into four categories based on their physiological effects; 65.7% of fibers were classified as soluble, non-viscous, readily fermented fibers. Bone outcomes were condensed into eight categories based on similarity; 35.9% of the outcomes were classified as calcium status and 12.8% were classified as magnesium status, bone resorption, and bone formation. Few studies assessed bone mass density (BMD) or bone mineral content (BMC) as an outcome (3.9%), and few were conducted for more than four months (8.57%). Future studies, of longer duration, which include other dietary fiber types, and focus on specific biomarkers of bone health (bone resorption, formation, turnover, and BMD/BMC) in conjunction with mineral status are warranted.