In a 2025 study from McMaster University, researchers analyzed nearly 16,000 adults from NHANES III to check if animal protein raises death risk from heart disease, cancer, or any cause. They found no link to higher mortality—animal protein even cut cancer death risk by a modest but significant amount. Plant protein showed no strong effects, but inflammatory diets with processed meats worsened outcomes.

In 2007, Begoña Cerdá and a team studied six volunteers whose fecal samples were incubated with ellagic acid, a soy polyphenol. They found gut bacteria turned it into urolithin, a compound tied to gut inflammation and potential cancer risk in animal studies, with 30-50% more urolithin production in some people, suggesting soy may harm gut health in certain individuals.