Conficts of interest in nutritional sciences: The forgotten bias in meta-analysis Michel Lucas Michel Lucas, Department of Social and Preventive Medicine, Université Laval, Population Health and Optimal Health Practices Research Unit, Centre Hospitalier Universitaire de Québec, Québec G1V 2M2, Canada Michel Lucas, Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA 02115, United States Author contributions: Lucas M conceived the idea of the manu- script, interpreted the data and wrote the manuscript. Conflict-of-interest statement: (1) Dr. Lucas is Assistant Professor at Université Laval since July 2012, and Visiting Scientist at the Harvard T.H. Chan School of Public Health. Full salary of Dr. Lucas comes from Université Laval and CHU de Québec, and is cover by a salary award from the Fonds de recherche du Québec - Santé (FRQS); (2) Between 1999 and 2012, while he was a student, Dr. Lucas often spoke at conferences (mainly on omega-3 fatty acids). His honoraria and expenses were covered by private industries. He has never received research funding from private industries; (3) Dr. Lucas has no relationships with entities that might have an interest in the submitted work; (4) Dr. Lucas’ spouse, children and partners have no fnancial relationships with the submitted work; and (5) Dr. Lucas does not have any non- fnancial interests in the submitted work. Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/ licenses/by-nc/4.0/ Correspondence to: Dr. Michel Lucas, Assistant Professor, Department of Social and Preventive Medicine, Université Laval, Population Health and Optimal Health Practices Research Unit, Centre Hospitalier Universitaire de Québec, 2875 Laurier Blvd., Delta 2 Building, Suite 600, Québec G1V 2M2, Canada. michel.lucas@crchuq.ulaval.ca Telephone: +1-418-5254444 Fax: +1-418-6542726 Received: May 22, 2015 Peer-review started: May 22, 2015 First decision: August 19, 2015 Revised: September 14, 2015 Accepted: September 29, 2015 Article in press: September 30, 2015 Published online: December 26, 2015 Abstract Awareness of conflicts of interest (COI) in medicine began in the 1980s. More recently, the problem has gained notoriety in nutritional sciences. COI with industry could bias study conclusions in the context of research activities and scientific publications on nutritional sciences. The issue of COI in nutritional sciences deserves more attention and requires careful analyses as biased information can negatively impact the development of dietary guidelines and, ultimately, population health. Decision-making is generally based on available, published evidence, but when the results are ambivalent, it is easier to opt for the status quo and ask for more studies. Readers might wonder if research is subsidized by industry as a counterbalancing strategy based on levels of evidence-only to slow down eminent positions and/or legislation on the food sector? How can this problem be overcome without producing paranoia and McCarthyism while trying to be as methodological as possible? Key words: Conflicts of interest; Nutrition; Nutritional sciences; Bias; Systematic reviews; Meta-analysis © The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved. Core tip: Decision-making in the field of nutrition is based on published evidence, but when results are ambivalent, it is easier to opt for the status quo and ask for more studies. Because conflicts of interest (COI) in nutritional sciences can bias conclusions and negatively impact dietary recommendations and population health, EDITORIAL 175 December 26, 2015|Volume 5|Issue 4| WJM|www.wjgnet.com Submit a Manuscript: http://www.wjgnet.com/esps/ Help Desk: http://www.wjgnet.com/esps/helpdesk.aspx DOI: 10.5662/wjm.v5.i4.175 World J Methodol 2015 December 26; 5(4): 175-178 ISSN 2222-0682 (online) © 2015 Baishideng Publishing Group Inc. All rights reserved. World Journal of Methodology WJM