In medicine it sometimes happens that the bad guys are not so bad and the good guys are not so good. It often depends on the quantity, the timing or even the ability to separate the wheat from the chaff. For example, a biological weapon like mustard gas gave rise to one of the most effective drugs against cancer, chemotherapy; Vitamin A, on the other hand, is an essential substance for the formation and maintenance of soft tissue and bones and has antioxidant functions. However, an excess of this nutrient can lead to skin problems, bone weakness, and joint pain. Nuances are always important. And this is proven once again by a study published today in the journal Nature, which turns the screw on nutrition again and concludes that there is a nutrient in red meat – a food that nutrition experts A healthy diet – which improves the immune response against cancer – should be severely restricted. After conducting laboratory studies with animal models and human cells, scientists conclude that transvaccenic acid, a trans fatty acid found in beef, milk or butter, has potential as a dietary supplement to optimize the effects of immunotherapy in oncology. In any case, experts advise caution when interpreting the results.
A group of researchers at the University of Chicago focused on the nutrients circulating in the blood, about 700 substances such as organic metabolites, lipids or proteins, among others, that could play a role in health and disease. “There are still many things we don’t know; For example, there is still no comprehensive understanding of the various physiological and pathological functions of each nutrient in different foods. “Our study attempted to address this dilemma,” says study author Jing Chen, professor in the Department of Medicine and director of the Cancer Metabolomics Research Center at the University of Chicago.
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The scientists examined a kind of library of more than 200 dietary nutrients circulating in the blood and examined which of them had a function or could influence antitumor immunity. Their research found that a particular trans fat, transvaccenic acid (TVA), promotes the ability of a type of immune system cell (CD8+ T lymphocytes) to infiltrate tumors and kill malignant cells. “Of course, only 19% and 12% of the TVA in the diet of humans and mice, respectively, can be converted into rumen acid, so TVA is not a typical nutrient only for energy production or as a building block for the biosynthesis of macromolecules. Our study shows that TVA has regulatory functions,” continues Chen.
Experiments with mice showed that the introduction of a diet enriched with this trans fat reduced the ability of melanoma and colon cancer tumor cells to expand compared to animals fed a control diet. Research also found that a TVA-enriched diet helps CD8+ T cells better infiltrate tumors. “Our studies in mouse models demonstrate the antitumor activity of TVA by improving CD8+ T cell function. This justifies future clinical trials using TVA as an adjunct to treatment with T cell-based immunotherapies,” defends Chen.
The scientists also tested what happened when some treatments were combined with this nutrient and found that adding dietary TVA to a type of immunotherapy showed “a synergistic attenuation of tumor growth.” In another retrospective clinical study, the authors found that patients with lymphoma who had higher TVA levels responded better to CAR-T, another type of immunotherapy that involves collecting T lymphocytes from patients for use in the Laboratory to improve and reinject them into the body so that it can better detect and kill cancer cells. “These results are consistent with the idea that dietary TVA could improve the clinical response to T cell-based immunotherapies,” the researchers suggest.
According to the authors, this study opens the opportunity to further examine the potential effects of circulating nutrients on health and disease. In the case of TVA, the scientists add, there are epidemiological studies that suggest that circulating levels of this trans fatty acid are associated with less obesity, lower risk of diabetes and less inflammation in humans, despite having effects on the cancer and cardiovascular system -Risk of diseases is unclear. Chen admits that it is not yet known whether this nutrient can be harmful in other contexts or for other conditions, but emphasizes: “TVA is not a bad trans fatty acid because previous studies have shown this in models of dyslipidemia.” [alteración de los niveles de grasa en sangre] “In rodents, the TVA-enriched diet has a hypolipidemic effect by reducing circulating triglycerides.”
Focus on the nutrient and not the food
However, Chen and his team emphasize that we must try to “comprehensively” understand all the influences and interactions that may occur between nutrients in order to choose the right diet. “Red meat consumption may provide TVA to enhance antitumor immunity, but high red meat consumption has been positively associated with the risk of many tumors, including breast or colon tumors,” they illustrate. In fact, the authors make it clear that their studies demonstrate “TVA supplementation as a more specific and efficient way to improve antitumor immunity than dietary changes.”
“Our results suggest that a balanced diet is likely to be good for 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 efficient than consuming foods containing these nutrients,” agrees Chen. The scientist assures that “TVA, as a natural food component, has a high translation potential to be used as a dietary component or treatment supplement in therapeutic approaches to improve clinical outcomes.” And he gives several examples: “A combination of TVA and immune checkpoint inhibitors could “Be tested to improve immunotherapies to treat cancer patients.” TVA can be combined with specific T cell activators, such as: [el medicamento] “Blinatumomab to treat patients with B-cell acute lymphoblastic leukemia or with CAR-T cells to improve effectiveness in treating cancer patients.”
Miguel Quintela, director of the clinical research program of the National Cancer Research Center (CNIO) and leader of a spin-off (TCNterapia) for personalized oncology nutrition, warns that although this study is “a very important first observation,” it no longer allows us to make a recommendation to citizens: “I cannot recommend my cancer patients to eat a steak.” “An experimental demonstration is one thing, it is another to see in the long term whether it actually increases a pathology or decreased.” The oncologist admits that the results of the research in which he did not participate seem “robust,” but you have to know how to interpret and contextualize them, that’s practical. “Nowadays you can’t make a list of pure nutrients and eat nothing else. Each nutrient is found in foods with a complex composition. The end consumer cannot isolate this nutrient from the meat. But this study opens up further fields of study,” he says.
According to Quintela, this research represents a boost for precision nutrition. “We have to spin it much finer,” he says. And there are lots of: “[El TVA] It is a saturated transacid that, according to nutrition experts, we should not eat, and which itself has lipid-lowering, anti-inflammatory, anti-diabetogenic and anti-tumor effects and promotes the anti-tumor immune response. In other words: It is a transacid that has a positive effect on health.” The oncologist gives a final thought: “Ultimately, a food is made up of hundreds of different molecules. Worldwide, the effects of red meat are likely to be bad, as numerous epidemiological studies have shown. However, that does not mean that it does not contain specific nutrients that perform beneficial functions. Therefore, it is necessary to take a precise approach and not rely on the generalities that we hear everywhere.”
Be careful with the results
Antoni Agudo, head of the Department of Nutrition and Cancer at the Catalan Institute of Oncology, considers the study, in which he was not involved, to be “very well documented”, but urges caution when interpreting the results: “TVA has been proven to have quite a specific effect, namely the reprogramming of CD8+ T cells to activate immunity. But the immune system has many pathways and this is just one of them. This means it may have potential in some types of tumors or in people receiving a particular treatment, but not in cancer generally.”
In addition, Agudo emphasizes that these findings are described “in animal models and in human cells in vitro.” “There is a long way to go from observing the effects in animals to their effect, if any, in clinical practice.”
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