In July 2018 researchers from Italy and the UK published their review of the medical scientific literature to assess the association between citrus intake and the risk of cancer of the oral cavity and pharynx. A total of 17 studies were included in the review. Results showed that those individuals with the highest citrus fruit intake had a 50% reduction in risk of oral cavity and pharyngeal cancer when compared to those with the lowest intake.
Cirmi S et al. Citrus fruits intake and oral cancer risk: A systematic review and meta-analysis. Pharmacol Res. 2018 Jul;133:187-194