Yeast food supplement helps immune cells fight cancer more effectively

Researchers from Trinity College Dublin (TCD) and University College Dublin (UCD) have shown for the first time that a food supplement made from yeast helps the body to make stronger immune cells that can fight cancer.

The research teams found that adding a yeast-based supplement to the food of obese laboratory mice changes how their immune cells grow and help to make better cancer‑fighting cells.

Being overweight can weaken the immune system, making it harder for the body to fight tumors. The yeast supplement helps fix this problem. This means that yeast-based supplements could become a safe and natural way to help the immune system fight cancer more effectively.

The findings of the research study, led by Associate Professor Frederick J Sheedy, Associate Professor in Immunology, TCD School of Biochemistry & Immunology and Professor Helen Roche, Professor in Nutrigenomics, UCD School of Public Health, Physiotherapy and Sports Science and Director, UCD Conway Institute, have been published in the scientific journal, Cell Reports.

We wanted to investigate whether a common dietary supplement (yeast beta-glucan) could reprogramme early-stage immune cells in the bone marrow to produce long-lasting, enhanced anti-tumor immune responses.

Mice were fed a standard or high fat diet supplemented with yeast beta-glucan for 4-12 weeks and then their immune system was challenged by different types of cancer cells (colorectal, skin and breast cancer). The study also tested whether yeast supplementation could overcome immune dysfunction caused by obesity and whether protective effects persist after weight loss."

Dr. Anna Ledwith, postdoctoral researcher in the Roche group and first author on the paper

Commenting on the significance of the findings, Professor Helen Roche said, "This is the first demonstration that dietary delivery of yeast beta-glucan is sufficient to induce trained immunity through reprogramming of bone marrow stem cells. Previous research required injections.
Crucially, this dietary intervention restores anti-tumor innate immunity in obese mice and reverses long-term immune memory defects that persist even after weight loss, a major unmet clinical challenge."

Obesity affects millions of people worldwide and profoundly disrupts the immune system, increasing the risk of infections and cancer. Even after weight loss, immune defects persist.

At the same time, cancer remains a leading cause of death globally. There is an urgent need for safe, accessible strategies to restore immune function. Yeast beta-glucan is already used as a food supplement and has an excellent safety record, making it a realistic candidate for clinical translation.

Looking to the future, Professor Frederick Sheedy said," This research paves the way for dietary intervention studies in people living with obesity, chronic infections and other immunocompromised populations. The yeast beta-glucan used (WellmuneTM, from Kerry Group) is already food-grade and commercially available, facilitating rapid clinical trials. Ultimately, a simple dietary supplement could help boost the immune system's cancer fighting ability, complementing existing treatments such as chemotherapy and immunotherapy, with potential to improve vaccine responses and resistance to infection."