In this cohort, an apple a day could keep the doctor away

摘要

A number of issues need resolution in terms of the potential health benefits of dietary fiber, and the article by Buil-Cosiales et al. (1) in this issue of the Journal addresses most of them. Rather than being a study on total fiber intake and risk of one specific disease, Buil-Cosiales et al. have addressed all-cause mortality, parsed out the major causes of that mortality, and included intake of whole grains, fruit, and vegetables in their analyses in addition to total fiber. This study is a hybrid of a randomized controlled trial (RCT)4 and an observational study, analyzed (appropriately) as an observational study. Being part of the parent 7447-person RCT provides important additional information such as whether or not increasing fruit or fiber consumption over an ~6-y follow-up has an effect on all-cause mortality. In addition, diet records were taken annually as part of the RCT, and Buil-Cosiales et al. used these repeated measurements of dietary information in their analyses, rather than just having one initial diet assessment at the beginning of a cohort study, or just before and after values for intervention trials. Also of note is that the subjects in this study are elderly and all are at "high risk" of cardiovascular disease (CVD; having hypertension or type '2 diabetes or other risk factors) rather than most trials, which screen for only "healthy people." Given the breadth and novelty of this study, we now address what we can take from it that will help advance our knowledge of fiber intake and health.