Removing meat from the plate is not an insurance policy against cancer. That is what the largest study currently available on the subject reveals.

For years, we have been told a comforting, seductive, almost magical story: that eliminating animal foods from our diet would act as a sort of insurance policy against cancer. More plant-based foods, lower cancer risk. Simple, right? Unfortunately, also simplistic. And science, when examined on a truly large scale, rarely confirms simplistic narratives. It is no coincidence that the largest study currently available on the topic points in a very different direction.

Published in the British Journal of Cancer just a few weeks ago (Dunneram Y et al., “Vegetarian diets and cancer risk: pooled analysis of 1.8 million women and men in nine prospective studies on three continents”, Br J Cancer, April 2026;134(8):1218–1229), the study followed more than 1.8 million people for approximately sixteen years, analysing over 200,000 cancer diagnoses. Numbers that, by themselves, are enough to shift the weight of the discussion. What emerges is not a triumph of vegan diets, but a far more uncomfortable reality: the relationship between diet and cancer is not linear at all, and the most restrictive diets are not necessarily the most protective.

Vegetarians do, in fact, show a reduced risk for certain cancers. But that is only half of the story, the half that, for years, has been selectively highlighted and amplified far beyond proportion. The other half, much less discussed, is that the same group shows a marked increase in oesophageal squamous cell carcinoma, nearly doubled compared to meat eaters. This is not a marginal statistical detail, but a signal that remains even after adjusting for smoking, alcohol consumption, body weight, and lifestyle factors. The authors point to possible nutritional deficiencies, particularly in micronutrients more abundant in animal foods, such as riboflavin and zinc. It is not definitive proof, but it is a biologically coherent hypothesis. Above all, it is a finding that challenges a deeply rooted assumption: eliminating animal foods from the diet is not a neutral act.

When we look at vegans, the picture becomes even more complicated. The most surprising finding of the study is a 40% increase in colorectal cancer risk compared to meat consumers. A result that directly contradicts the mantra that high fibre intake and the absence of steaks automatically guarantee protection. Of course, the researchers urge caution: the number of cases is small and further confirmation is needed. But the signal is there, and from a physiological standpoint, it is far from implausible. Across all cohorts analysed, vegans had the lowest calcium intake. And for years now, robust epidemiological evidence has shown that calcium and several dairy products are associated with a reduced risk of colorectal carcinoma. Once again, the point is not to assign blame, but to recognise a plausible biological mechanism.

The paradox becomes evident when observing the groups with the most favourable risk profiles. They are not the “purest” or the most restrictive eaters. They are those who do not eliminate animal foods, but rather select them carefully. Pescatarians, for example, show reduced risks for several cancers. Likewise, individuals who consume white meat while reducing red and processed meat intake display a more favourable risk profile for certain malignancies. This is not a victory for meat itself, but for nutritional moderation, a concept that is far less ideological and much harder to market.

At this point, it becomes unavoidable to address the central issue that has been carefully sidestepped for years: nutritional deficiencies. Because when entire categories of foods are excluded, the problem is not only what is avoided, but also what is inevitably lost. Calcium, vitamin B12, zinc, vitamin D, riboflavin, iodine, and highly bioavailable iron are not obscure details from a biochemistry textbook. They are nutrients involved in fundamental processes such as DNA repair, immune function, metabolism, and tissue integrity. To assume that they are irrelevant in the long term, or, even worse, that plant-based diets can always and easily provide adequate amounts of these micronutrients, is more an act of faith than a scientific position.

Naturally, the study is observational and does not prove causality. This is the first limitation the authors themselves acknowledge. There is always the possibility of residual confounding, since vegetarians tend to smoke less, drink less alcohol, and exercise more. But this actually strengthens the point: even after adjusting for these factors, differences persist that cannot be dismissed with a shrug. The message is not that plant-based diets are harmful, but that they are not automatically protective. And, above all, the idea of an intrinsic superiority of vegan diets is not supported by the strongest data currently available.

The real mistake, perhaps, has been turning a dietary approach into an identity. When diet becomes ideology, physiology takes a back seat. The study, published in the British Journal of Cancer, instead brings us back to a far less glamorous but far more useful principle: what matters most is not what is eliminated, but the overall nutritional intake. The most protective diets, including from an oncological perspective, are not those based on extremes, but those that maintain genuine nutritional balance.

This research does not demolish plant-based diets. What it does demolish is the idea that they are automatically superior. At the same time, it delivers an uncomfortable lesson: nutrition does not follow the moral trends of the moment. The human body continues to function according to biological processes, micronutrient requirements, and metabolic balance. Even with the best intentions, ignoring this comes at a cost.