Whole grain consumption and human health: an umbrella review of observational studies
Maria Tieri, Francesca Ghelfi, Marilena Vitale, Claudia Vetrani, Stefano Marventano, Alessandra Lafranconi, Justyna Godos, Lucilla Titta, Angelo Gambera, Elena Alonzo, Salvatore Sciacca, Gabriele Riccardi, Silvio Buscemi, Daniele Del Rio, Sumantra Ray, Fabio Galvano, Eleanor J. Beck, Giuseppe Grosso
Abstract
Whole grains have been associated with a number of health benefits. We systematically reviewed existing meta-analyses of observational studies and evaluated the level of evidence for their putative effects based on pre-selected criteria. Of the 23 included studies, we found convincing evidence of an inverse association between whole grain consumption and risk of type-2 diabetes and colorectal cancer; possible evidence of decreased risk of colon cancer and cardiovascular mortality with increased whole grain intake, as well as increased risk of prostate cancer. Limited or insufficient evidence was available for all other outcomes investigated. Overall findings are encouraging for a positive effect of whole grain consumption on certain diseases, especially highly prevalent metabolic diseases, however, uncertainty of some negative associations deserves further attention.