Vitamin C study suggests cancer prevention role

University of Waterloo researchers said on May 20 that a mathematical modelling study suggests vitamin C can reduce digestive chemical reactions associated with cancer risk. The work examined how nitrates and nitrites in food and water behave in the body, and how vitamin C changes those reactions over time. The researchers said the findings could help explain why earlier studies on nitrates, nitrites and cancer have produced mixed results. The paper, titled “Vitamin C as a nitrosation inhibitor: A modelling study across dietary patterns and water quality,” was published in the *Journal of Theoretical Biology*. ### Which digestive reaction did the researchers focus on? The University of Waterloo study focused on nitrosation, a stomach reaction in which nitrates and nitrites can be converted into compounds that many scientists suspect increase cancer risk. The researchers said exposure to those compounds has risen over several decades in North American diets through cured meats and produce grown in polluted soil and water. (uwaterloo.ca) Nitrates and nitrites also have normal biological roles, including in neurological and heart health, according to the Waterloo release. The study did not say vitamin C prevents cancer in people; it said the modelling points to a mechanism that may affect the formation of nitrosation products linked to cancer risk. ### What exactly did the model simulate? Gordon McNicol, a post-doctoral researcher in applied mathematics and the paper’s first author, said the team built a model of the salivary glands, stomach, small intestine and plasma. (uwaterloo.ca) The simulations tracked how nitrates and nitrites move through the body and change over time under different dietary conditions. The model showed that when vitamin C is present in food, including foods such as leafy greens that contain both vitamin C and nitrate, the formation of potentially harmful nitrosation products could be reduced, the researchers said. (uwaterloo.ca) McNicol said the presence of dietary vitamin C may help explain inconsistencies in earlier research dating back to at least the 1990s. ### Where are the nitrates and nitrites in question coming from? (uwaterloo.ca) The Waterloo release cited cured meats such as bacon and salami as examples of foods associated with dietary nitrites and nitrates. It also said fruits and vegetables can contribute exposure when they are grown in polluted soil and water. The paper’s title also refers to dietary patterns and water quality, indicating that the model was designed to compare exposure under different conditions rather than test a single food item. (uwaterloo.ca) The release did not provide a single exposure figure or dosage threshold for consumers. ### Did the researchers say anything about supplements? The study suggested that taking vitamin C supplements after meals could have a moderate positive effect in reducing the formation of nitrosation products associated with dietary nitrites and nitrates, according to the Waterloo release. (uwaterloo.ca) The researchers framed that as a modelling result, not a clinical recommendation. (eurekalert.org) Anita Layton, a professor of applied mathematics and Canada 150 Research Chair, said the work provides what she called a “mechanistic roadmap” for future clinical and laboratory studies. She said the model could help researchers target experiments and interventions by identifying when nitrosation is most likely to occur and which factors matter most, including meal timing, gastric conditions and oral microbiome activity. (uwaterloo.ca) ### What happens next? The Journal of Theoretical Biology paper carries the DOI 10.1016/j.jtbi.2026.112444, according to the publication details listed with the release. Waterloo researchers said the next step is to use the model to guide laboratory and clinical studies rather than treat the findings as direct proof of cancer prevention in humans. May 20 publication details identify McNicol and Layton among the named researchers attached to the study, and the university said it hopes the findings will support future nutrition research. (uwaterloo.ca) Those follow-up studies are the next named milestone in the work described so far. (eurekalert.org)