Gastric cancer is the third-leading cause of death from cancer across the globe. Helicobacter pylori treatment is one of the accepted treatments to prevent gastric cancer, but recent studies have also indicated the effectiveness of vitamin and gastric supplementation in preventing cancer. The objective of this study is to investigate the effects of Helicobacter pylori treatment, vitamin treatment, and garlic supplementation in the prevention of gastric cancer.

This is a blinded, randomized, placebo-controlled trial conducted in Linqu Country, China. The study included 3,365 residents at a high risk of gastric cancer. 2,258 participants seropositive to antibodies were assigned to H pylori, vitamin supplementation, garlic supplementation treatment, or placebos for two weeks. 1,107 participants who were seronegative to antibodies were assigned to vitamin supplementation and garlic supplementation treatment or placebos for seven years. The main outcome was the incidence of gastric cancer.

A total of 151 incidents and 94 deaths from gastric cancer were reported during the trial. The H pylori treatment resulted in a 22 years’ post-intervention protective effect. Vitamin supplementation also significantly reduced the incidence of cancer, but no significant reductions were noticed with garlic supplementation.

The research concluded that H pylori treatment for two weeks and vitamin or garlic supplementation for seven years resulted in a significant decrease in the risk of gastric cancer for more than 22 years.