Researchers from the RIKEN Center for Integrative Medical Sciences (IMS) in Japan have discovered that food proteins, typically associated with allergic reactions, can help suppress tumor growth in the small intestine. The study, published in Frontiers in Immunology, shows how these proteins trigger the immune system to prevent the formation of tumors, offering a new perspective on the relationship between diet and cancer prevention.
The research, led by Hiroshi Ohno, MD, PhD, focuses on how antigens from food, such as proteins found in meat and milk, interact with the body’s immune system in the gut. Although these proteins are usually monitored by the immune system as foreign substances—often the source of allergic reactions—they also play a role in activating immune responses that help maintain gut health.
Specifically, the research highlights how food antigens can prevent the growth of tumors in the small intestine, an area less prone to cancer than the colon but still of concern for people with genetic risks.
Using a mouse model prone to developing tumors throughout the intestines, the research team investigated how different diets impacted tumor growth. Mice were fed either a normal diet, an antigen-free diet, or an antigen-free diet supplemented with a common protein, albumin, which is present in meat. The findings were significant: mice on the normal diet had fewer tumors in the small intestine than those on the antigen-free diet. Similarly, the mice fed antigen-free food supplemented with albumin also showed tumor suppression, suggesting that the presence of food antigens is crucial for this protective effect.
To understand the underlying biological mechanism, the researchers examined how these food antigens interact with immune cells in the small intestine. Their focus was on Peyer’s patches, specialized immune structures that help process food antigens. They found that the patches passed food antigens to immune cells, particularly T cells, which are essential for tumor suppression. Mice on the antigen-free diet had significantly fewer T cells than those consuming normal food, demonstrating that food antigens were critical for maintaining the immune system’s ability to suppress tumors.
Using single-cell RNA sequencing, the researchers further revealed how food antigens affect immune cell activity. Their analysis showed that food antigens boosted the antigen-presenting abilities of dendritic cells, which in turn activated T cells within Peyer’s patches. This immune activation process was crucial in preventing tumors from developing in the small intestine.
The study’s findings have important implications for clinical practice. Elemental diets, which are devoid of whole proteins and used to manage severe gastrointestinal conditions like Crohn’s disease, may inadvertently remove beneficial food antigens that help protect against small intestinal tumors. Ohno cautions, “The clinical use of elemental diets to treat inflammatory bowel disease or other gastrointestinal conditions in these patients should be considered very carefully.”
These diets are sometimes adopted by individuals without medical conditions to reduce bloating or inflammation, but the study suggests that such practices could carry risks. Ohno notes that while small intestinal tumors are less common than colon cancer, “the risk is higher in cases of familial adenomatous polyposis,” a genetic condition that increases the risk of tumors in the intestines. In such cases, diets lacking food antigens could potentially increase the risk of tumor growth in the small intestine.
As scientists continue to explore the link between food antigens and tumor suppression, it becomes clear that balanced diets, rich in whole proteins, may play a more significant role in preventing cancer than previously thought.
