In medicine, sometimes the bad guys aren’t that bad and the good guys aren’t that good. This often comes down to quantities, timing, and even the ability to separate the wheat from the chaff. For example, chemotherapy, one of the most effective cancer treatments, was a byproduct of mustard gas, a biological weapon; Vitamin A is a substance necessary for the formation and maintenance of soft tissues and bones and has antioxidant properties, but its excess can cause skin problems, bone weakness and joint pain.
Nuances are always important. This has been proven once again by research published in the journal this week. NatureIt is concluded that red meat, a food that nutritionists recommend limiting as much as possible, contains a nutrient that improves the immune response against cancer. After conducting studies with animal models and human cells, the researchers concluded that trans-vaccenic acid, a trans fatty acid found in beef, milk and butter, has potential as a nutritional supplement to optimize the effect of immunotherapy in oncology. Still, experts recommend caution when interpreting the results.
A group of researchers from the University of Chicago focused on nutrients circulating in the blood—about 700 substances that may play a role in health and disease, including organic metabolites, lipids, and proteins. “There is a lot we don’t know yet. A comprehensive understanding of the various physiological and pathological functions of individual nutrients in different foods is still lacking. Our study sought to resolve this dilemma,” said study author Jing Chen, professor at the University of Chicago School of Medicine and director of the Center for Cancer Metabolomics Research. .
The scientists examined a library of more than 200 dietary nutrients circulating in the blood and examined which ones might play a role in or influence anti-tumor immunity. Their research revealed that a specific trans fat, trans-vaccenic acid (TVA), supports the ability of a type of immune system cells (CD8+ T cells) to infiltrate tumors and kill malignant cells. “Only 19% or 12% of dietary TVA can be converted to rumenic acid by humans or mice, so TVA is not a typical nutrient for energy or a biosynthetic building block for macromolecules. Our study shows that TVA has regulatory functions,” he notes. Chen.
Experiments with mice showed that a diet enriched with this trans fat reduced the expansion capacity of melanoma and colon cancer tumor cells compared to animals fed a control diet. The study also found that a TVA-enriched diet helped CD8+ T cells better infiltrate tumors. “Our studies in mouse models demonstrate the anti-tumor activity of TVA through improvement of CD8+ T cell function. This justifies future clinical studies using TVA as an adjunct to the treatment of T cell-based immunotherapies,” explains Chen.
Scientists also tested what happened when certain treatments were combined with this nutrient and found that dietary TVA added to a type of immunotherapy “showed a synergistic attenuation of tumor growth.” In another retrospective clinical study, the authors found that lymphoma patients with higher levels of TVA responded better to CAR-T, another type of immunotherapy that involves extracting T lymphocytes from patients and curing them in the laboratory so they can be better identified and treated. It kills cancer cells and then reinjects them into their bodies. “These findings are consistent with the idea that dietary TVA may increase clinical sensitivity to T cell-based immunotherapies,” the researchers say.
According to the authors, this study opens the door to more closely examine the potential roles of circulating nutrients in human health and disease. They add that in the case of TVA, there are epidemiological studies in humans that suggest that circulating levels of this trans fatty acid are associated with lower adiposity, diabetes risk, and systemic inflammation, but its effects on cancer and cardiovascular disease risk are unclear. . Chen admits that they still don’t know whether this nutrient would be harmful in other contexts or for other conditions, but he insists: “TVA is not a bad trans fatty acid, because previous studies have shown it to be harmful in models of dyslipidemia.” [abnormal levels of fats in the blood] TVA-enriched diet in rodents has hypolipidemic effects by reducing circulating triglycerides.
Focus on the food, not the food
However, Chen and his team emphasize that a comprehensive understanding of the interactive and collective effects of various nutrients on cancer risk, development, and treatment responses is crucial for dietary choices. “Consuming red meat may provide TVA for improved 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 write. The authors explain that what their study actually supports is “TVA supplementation as a more targeted and effective way to benefit anti-tumor immunity than dietary changes.”
“Our results 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 probably more efficient than consuming foods containing these nutrients,” says Chen. The scientist assures that “TVA, as a natural food ingredient, has high translational potential as a dietary element in therapeutic approaches to improve the clinical outcomes of various anti-cancer treatments.” He gives a few examples: “A combination of TVA and immune checkpoint inhibitors could be tested to develop immunotherapies to treat cancer patients. TVA can be combined with specific T cell activators such as: [the drug] “It may be used with blinatumomab to treat patients with B-cell acute lymphoblastic leukemia or with CAR-T cells to increase efficacy in treating patients with cancer.”
Although this study is a “very important first observation”, warns Miguel Quintela, director of the Clinical Research Program of the Spanish National Cancer Research Center (CNIO) and head of the personalized oncological nutrition (TCNterapia) spin-off. It’s too early to make recommendations. “I cannot recommend my cancer patients to eat steak. An experimental demonstration is one thing, another is to see if it actually increases a disease in the long term.” The oncologist admits that the results of the study, in which he was not involved, appear “robust” but that it is necessary to know how to interpret and contextualize them. “You can’t eat anything. Every nutrient is found in foods with a complex composition. The final consumer cannot separate this nutrient from meat. However, this study opens up further areas of study.”
What this research represents, according to Quintela, is a push for precision nutrition. “We need to be much more precise,” he says. “[TVA] It is a saturated fatty acid that nutritionists tell us not to eat, and it alone has lipid-lowering, anti-inflammatory, anti-diabetogenic and anti-tumor capacities and supports the anti-tumor immune response. In other words, it is a trans fatty acid that is beneficial to health.” Finally, the oncologist adds: “At the end of the day, a food consists of hundreds of different molecules. In general, the effect of red meat is probably bad, as evidenced by many epidemiological studies. However, this does not mean that there are not certain nutrients that have positive functions. Therefore, it is necessary to take a sensitive approach, beyond the generalizations heard everywhere.”
Common sense above all
Antoni Agudo, head of the Nutrition and Cancer Unit at the Catalan Institute of Oncology, thinks the study, which he did not participate in, is “very well documented” but urges “caution” in interpreting the results. “TVA has been shown to have a highly specific effect, which is the reprogramming of CD8+ T cells to activate immunity. But the immune system has many ways of acting, and this is just one of them. This has potential in some types of tumors or in people following a particular treatment.” “It means you can have it, but it doesn’t apply to every case of cancer.”
Agudo also emphasizes that these findings have been described “in animal experimental models and in vitro human cells.” “It’s a long way from effects seen in animals to having an impact in clinical practice.”
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