Aynaz Mohammadian - Student Research Committee, Khalkhal University of Medical Sciences, Khalkhal, Iran
Vahideh Aghamohammadi - Assistant Professor, Department of Nutrition, Khalkhal University of Medical Sciences, Khalkhal, Iran
Amirhosein Chamani - Student Research Committee, Khalkhal University of Medical Sciences, Khalkhal, Iran
Erfan Tarighi - Student Research Committee, Khalkhal University of Medical Sciences, Khalkhal, Iran
Arian Bandari - Student Research Committee, Khalkhal University of Medical Sciences, Khalkhal, Iran

Genetically modified (GM) foods have been the subject of extensive debate concerning their safety and potential health effects. One area of concern is their possible link to gastrointestinal (GI) cancers. The present review aimed to clarify the relationship between the consumption of GM foods and the incidence of GI cancers based on evidence from randomized controlled trials (RCTs). Methods: The present systematic review was executed according to the PRISMA protocol. A search was conducted on the Persian (SID, Magiran) and English (PubMed, Cochrane, Web of Science, Google Scholar, Scopus) databases from ۲۰۰۰ to June ۸, ۲۰۲۴. The inclusion criteria were RCTs that compared the incidence of GI cancers in populations consuming GM foods versus those consuming non-GM foods and were also limited to human studies. After searching all databases, ۱۲۳۷ articles were identified at this stage. The screening process of articles was conducted by five reviewers respectively. After title, abstract, or full-text reading and applying exclusion criteria, we reviewed ۱۲ studies on the consumption of GM foods and the incidence of GI cancers. Results: A total of ۱۲ RCTs met the inclusion criteria, including ۹۸۴۵ participants in the intervention and control groups, and the duration of the interventions varied from ۶ months to ۲ years. The studies varied in design, duration, types of GM foods examined, and study populations. According to the studies, overall, the RCTs did not provide consistent evidence of a significant association with gastrointestinal cancers between GM and non-GM food groups. ۲ trials reported mild gastrointestinal symptoms, but these symptoms were not consistently associated with GM food consumption. Also, considering the type of transgenic food, duration of exposure, and demographic factors, no significant relationship was observed. However, the trials were limited by short follow-up periods, small sample sizes, and potential biases. Conclusion: This systematic review of RCTs found no conclusive evidence to support a link between the consumption of GM foods and the risk of developing gastrointestinal cancers. The current body of RCT evidence is limited and marked by methodological constraints. However, the limited number of high-quality RCTs and the variability in study designs highlight the need for further long-term research to conclusively determine the safety of GM foods regarding GI cancer risk.

Genetically Modified Foods, Gastrointestinal Cancer, Cancer Risk, Food Safety