by In medicine, sometimes the bad guys aren’t so bad and the good guys aren’t so good. It is often about the sizes, the time or even the ability to separate the wheat from the chaff. Chemotherapy, for example, was one of the most effective cancer treatments, a by-product of mustard gas, which is a biological weapon; Vitamin A, on the other hand, is an essential substance for the formation and maintenance of soft tissues and bones and has antioxidant properties, but in addition it can cause skin problems, bone weakness and joint pain.
Nuances always matter. This is proven again by research published this week in the journal nature, concluded that red meat – a food that nutrition experts recommend limiting as much as possible – is a nutrient that improves the immune response against cancer. After conducting studies with animal models and human cells, the researchers concluded that trans-vaccine acid, a trans-fatty acid found in beef, milk and butter, could be a dietary supplement to improve the impact of immunotherapy in oncology. optimization. Still, experts advise caution when interpreting the results.
A group of researchers from the University of Chicago focused on the nutrients circulating in the blood, about 700 substances including organic metabolites, lipids and proteins, which may play a role in health and disease. “There’s a lot we don’t know yet. A comprehensive understanding of the different physiological and pathological functions of each nutrient from different foods is not yet available. Our study tried to address this dilemma,” says study author Jing Chen, professor in the Department of Medicine and director of the Cancer Metabolism Research Center at the University of Chicago.
The scientists reviewed a library of more than 200 nutrients derived from diet that circulate in the blood, and studied those that may play a role or influence anti-tumor immunity. Their research showed that a particular trans-fatty, trans-vaccinic acid (TVA) promoted the ability of a cell type of the immune system (CD8+ T cells) to infiltrate tumors and kill malignant cells. “Humans or mice can only convert about 19% or 12% of dietary TVA to rumenic acid, respectively, so TVA is not a normal nutrient for energy or as a biosynthetic building block for macromolecules. Our study shows that TVA has regulatory functions,” says Chen.
The experiments with mice showed that a diet enriched with this trans fat reduced the proliferation capacity of melanoma and colon cancer tumor cells, compared to those animals fed a control diet. The research also showed that a TVA-enriched diet helps CD8+ T cells to better infiltrate tumors. “Our studies in mouse models demonstrate the anti-tumor activity of TVA by enhancing CD8+ T cell function. This justifies future clinical studies using TVA as an adjunct to treatment for T-cell-based immunotherapy,” explains Chen.
The scientists also tested what happened when several treatments were added to this nutrient, and found that TVA fed with a type of immunotherapy showed a “synergistic reduction in tumor growth.” In another retrospective clinical study, the authors noted that lymphoma patients with higher levels of TVA responded to CAR-T, another type of immunotherapy that involves removing T lymphocytes from patients to enhance them in the laboratory so they recognize and kill cancer cells, and then re-inject them into their body. “These results align with the notion that dietary TVA may improve clinical responsiveness to T-cell-based immunotherapy,” suggest the researchers.
According to the authors, this study opens the door to a deeper exploration of the possible roles of circulating nutrients in human health and disease. In the case of TVA, they add, there are epidemiological studies that suggest circulating levels of this trans fatty acid in humans are associated with lower adiposity, risk of diabetes and systemic inflammation, although its effects on cancer risk are not and clear cardiovascular disease. . Chen admits that they do not yet know whether this nutrient can be harmful in other contexts or for other illnesses, but insists: “TVA is not a bad trans fatty acid, as previous studies have shown in models dyslipidemia. [abnormal levels of fats in the blood] in rodents, a TVA-enriched diet has hypolipidemic effects by reducing circulating triglycerides.”
Focusing on the nutrient, not the food
However, Chen and his team emphasize that a comprehensive understanding of the interactive and collective influences of multiple dietary nutrients on cancer risk, development and therapy responses is critical to dietary choices. “Red meat consumption can provide TVA for enhanced anti-tumor immunity, but high red meat intake is positively associated with the risk of many cancers, including breast, colorectal, colon and rectal cancer,” they wrote. The authors clarify that, in fact, what their study supports is “TVA supplementation as a more targeted and effective way than dietary changes to benefit anti-tumor immunity.”
“Our findings suggest that a balanced diet is probably good for your health. It may be more important to focus on the bioactivity of nutrients rather than individual foods, and taking supplements with enriched bioactive nutrients is likely to be more effective than eating foods that contain these nutrients,” says Chen. The scientist asserts that “as a natural food component, TVA has a high translational potential as a dietary element in therapeutic approaches to improve the clinical results of various anti-cancer therapies.” He cites several examples: “Combinations of TVA and immune checkpoint inhibitors could be tested to improve immunotherapy to treat cancer patients. TVA can be combined with specific T-cell activators such as [the drug] blinatumomab, to treat patients with acute B-cell leukemia, or with CAR-T cells to improve efficacy in the treatment of cancer patients.”
Miguel Quintela, director of the Clinical Research Program of the Spanish National Cancer Research Center (CNIO) and leader of the spin-off of personalized oncological nutrition (TCNterapia), warns that although “this study is a very important first observation,” it is too early to start issuing recommendations. “I cannot recommend to my colon cancer patients to eat. It’s one thing to demonstrate experimentally, it’s another thing to see, in the long term, whether it increases or decreases disease.” The oncologist admits that the results of the research, which he did not participate in, seem “strong,” but you need to know how to interpret them and put them in context. “Right now, you can’t make a list of pure nutrients and eat nothing but that. All nutrients come in foods of complex composition. The final consumer cannot isolate that nutrient from the meat. However, this study opens up more areas of study.”
What this research shows, in Quintela’s view, is a boost to precise nutrition. “We need to be much more precise,” he says. “[TVA] It is a saturated fatty acid, which nutrition experts tell us not to eat, and in itself has lipid-lowering, anti-inflammatory, anti-diabetogenic and anti-tumor abilities, promoting the anti-tumor immune response. In other words, it is a trans fatty acid that is beneficial for health.” The oncologist adds a final thought: “At the end of the day, food is made up of hundreds of different molecules. Overall, it is likely that the effect of red meat is bad, as proven by many epidemiological studies. But that does not mean that there are not specific nutrients that perform positive functions. So a precise approach is necessary, rather than the generalizations that are heard everywhere.”
Above all, prudence
Antoni Agudo, head of the Nutrition and Cancer Unit of the Catalan Institute of Oncology, thinks that the study, which he did not participate in, is “very well documented,” but appeals for “prudence” when interpreting the results. “TVA has been shown to have a relatively specific effect, which is the reprogramming of CD8+ T cells to activate immunity. But the immune system has many ways of action and this is just one of them. This means that it may have potential in some types of tumors or in people who are following a specific treatment, but not in all cases of cancer.”
In addition, Agudo emphasizes, these results are described “in experimental animal models and in human cells in vitro.” “It’s a long way from the effects being seen in animals to having an impact – if ever – on clinical practice.”
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