Exploring how diet and the gastric microbiome shape gastric cancer risk

Gastric cancer (GC), commonly known as stomach cancer, ranks as the world's fifth most common cancer and the third leading cause of cancer-related deaths, claiming over 784,000 lives annually. While historically more prevalent in older adults, GC is increasingly affecting younger individuals in developed countries. This has raised alarms among researchers, as it signals a shift in risk factors that are just now beginning to be understood.

Helicobacter pylori, a species of bacteria, is one of the main culprits behind GC. H. pylori bacteria currently infects roughly half of the global population. However, this infection alone does not explain why fewer than 3% of individuals harboring H. pylori actually develop cancer. Recent research has revealed the role of an additional factor: the complex community of microorganisms living in the digestive tract that may play a crucial role in determining who ultimately develops this deadly disease. Since diet strongly influences the gut microbiota, this interaction likely affects cancer risk.

Against this backdrop, a research team led by Professor Jun Yu from the State Key Laboratory of Digestive Disease at the Chinese University of Hong Kong conducted a comprehensive analysis of how diet, gastric microorganisms, and their chemical byproducts interact to either promote or prevent GC. Their extensive review, published online in the journal Research on May 12, 2025, aptly summarizes our current understanding of these complex relationships and points toward new prevention strategies.

The researchers' analysis indicates that certain dietary patterns create an environment in the stomach that favors GC development. High-salt foods, particularly salt-preserved items common in many Asian cuisines, directly damage the stomach lining and create conditions that help harmful bacteria flourish. Similarly, processed meats generate cancer-causing compounds, such as heterocyclic amines and polycyclic aromatic hydrocarbons, when cooked at high temperatures. Heavy alcohol consumption contributes to GC development by producing toxic metabolites that damage cellular structures in the stomach, while high-fat diets promote inflammation and accelerate tumor progression.

Notably, recent technological advances have opened new avenues for understanding how microorganisms shape GC development. Elaborating on this, Prof. Yu says, “Microbial profiling technology has facilitated investigations on microbes residing on the gastric mucosa, and increasing evidence has revealed the critical roles of non-Helicobacter pylori gastric microbes in gastric tumorigenesis.” The review highlights specific harmful bacteria that become more abundant in stomach cancer patients, including Streptococcus anginosus and Fusobacterium nucleatum. These microorganisms do not just passively inhabit the stomach—they actively participate in cancer development by producing toxic chemicals, promoting inflammation, and helping tumors evade the immune system. For example, S. anginosus depletes an amino acid crucial for immune cells to function properly, essentially disarming one of the body's natural mechanisms for fighting cancer.

Conversely, beneficial bacteria such as Akkermansia muciniphila and various butyrate-producing species help protect against cancer by strengthening the immune response and maintaining healthy stomach conditions. The harmful dietary patterns outlined above tend to reduce populations of these protective microorganisms while promoting the growth of harmful species.

The researchers also point toward promising intervention approaches, including targeted dietary modifications and microbiome-based therapies. Just like an unhealthy diet contributes to GC risk, a healthy diet causes the opposite effect. “Diets rich in fruits and vegetables and low in processed meat and salty foods can substantially lower the risk of GC," highlights Prof. Yu. Some studies have shown that compounds found in broccoli sprouts can reduce H. pylori colonization, while walnuts exhibit anti-cancer properties by reducing inflammation and supporting cellular defense mechanisms. In the near future, more sophisticated approaches to combat GC might involve engineered probiotics designed to outcompete harmful bacteria or precision nutrition strategies tailored to an individual's microbiome profile.

In summary, this comprehensive review provides a roadmap for future research in GC and promising clinical developments and suggests that preventing this disease may require a multifaceted approach, addressing both dietary habits and the gastric microbiome. As the global burden of GC continues to rise, these insights will hopefully lead to more effective treatment and prevention strategies for this public health threat.  

About The Chinese University of Hong Kong

The Chinese University of Hong Kong (CUHK), a heavily research-focused institution, has made its global vision and mission to combine tradition with modernity, hoping to bring together China and the West. Established in 1963, CUHK is known for its bilingual and bicultural heritage, strong international outlook, and commitment to academic excellence. The university hosts a diverse range of world-class research programs across disciplines, including medicine, engineering, humanities, and environmental science. It is also the only University in Hong Kong to offer a college experience, located in a beautiful 138.4 hectare campus overlooking Tolo Harbour.

Official website: https://www.cuhk.edu.hk/ 

About Research by Science Partner Journal

Launched in 2018, Research is the first journal in the Science Partner Journal (SPJ) program. Research is published by the American Association for the Advancement of Science (AAAS) in association with Science and Technology Review Publishing House. Research publishes fundamental research in the life and physical sciences as well as important findings or issues in engineering and applied science. The journal publishes original research articles, reviews, perspectives, and editorials. IF=10.7, Citescore=13.3.

Sources: https://spj.science.org/doi/10.34133/research.0693