A fatty acid prevalent in beef, lamb, and dairy products enhances the immune system's ability to fight cancer cells, researchers have found.
A study, published in the journal Nature, found trans-vaccenic acid (TVA) can deactivate receptors involved in regulating immune responses and change how the immune system acts against cancer cells.
The team, led by Dr Jing Chen, the Janet Davison Rowley Distinguished Service Professor of Medicine at the University of Chicago, focused on the effects of TVA on immune cells.
Previous studies have linked high consumption of red meat and processed meat with an increased risk of certain types of cancer, notably colorectal cancer.
However, the researchers warned against increasing red meat and dairy consumption. Instead, the focus should be on the nutrient itself, potentially in supplement form.
Dr Chen said: “Our results suggest that taking a balanced diet is probably good for health.”
Speaking to The National, Dr Chen said the research has shown for the first time that TVA can switch off a specific receptor (GPR43) on the surface of cells.
This receptor normally responds to certain substances produced by the bacteria in our gut. By deactivating this receptor, TVA can change how the body's immune system works in a way that could help fight cancer.
“There are many studies trying to decipher the link between diet and human health. By focusing on nutrients that can activate T-cell responses, we found one that actually enhances anti-tumour immunity,” Dr Chen explained.
Dr Chen's laboratory, along with postdoctoral fellows Hao Fan and Siyuan Xia, co-first authors of the study, began by analysing approximately 700 known food-derived metabolites – small molecules resulting from the body's processing of food.
Their research zeroed in on 235 bioactive molecules, eventually identifying TVA as a top candidate for enhancing anti-tumour immunity.
TVA, which cannot be produced by the body and is abundant in human milk, remains largely unbroken down in the bloodstream.
“That means there must be something else it does, so we started working on it more,” Dr Chen added.
Subsequent experiments with cell and mouse models showed that a TVA-enriched diet significantly reduced tumour growth in melanoma and colon cancer cells.
“As a natural food component, TVA has high translational potential to be used as a dietary element or a treatment supplement in therapeutic approaches to ameliorate clinical outcomes.” he told The National.
“For example, a combination of TVA and immune checkpoint inhibitors could be tested for improved immunotherapies to treat cancer patients.”
Dr Justin Kline, medical oncologist at the University of Chicago, analysed blood samples from patients undergoing CAR-T cell immunotherapy for lymphoma, noting that higher TVA levels corresponded with better treatment responses.
Additionally, Prof Wendy Stock, professor of medicine-hematology and oncology, observed enhanced effects of an immunotherapy drug on leukaemia cells in the presence of TVA.
“There are still many things that we don’t know, for example, a comprehensive understanding of diverse physiological and pathological functions of each nutrient from different foods is still not available,” Dr Chen told The National.
“Focusing on bioactivity of nutrients rather than individual food might be more important; and taking supplements with enriched bioactive nutrients is likely more efficient than consuming foods containing these nutrients.”
Dr Chen also hinted at the possibility of similar benefits from plant-derived fatty acids.
Research, including large-scale epidemiological studies, has often shown that high consumption of processed meats (such as sausages) and red meats (such as beef and lamb) is associated with an increased risk of certain types of cancer, notably colorectal cancer.
The World Health Organisation classified red meat as a Group 2A carcinogen, indicating that is probably carcinogenic to humans.
These classifications were based on evidence suggesting these meats can lead to DNA damage and increase the risk of cancer, potentially due to substances formed during processing or cooking at high temperatures. There's also some evidence that high meat consumption might influence gut bacteria in ways that contribute to cancer risk.
