Black Walnut for Digestive Health

Research on black walnut and digestive health is extremely limited, with only a single animal study identified in the available literature. That study, conducted in horses, examined the gastrointestinal effects of black walnut extract and found inflammatory and apoptotic changes in colon tissue, suggesting the extract can produce notable biological activity in the gut — though in a harmful rather than therapeutic direction. Studies indicate that this evidence does not support conclusions about beneficial digestive effects in humans, as the context was one of toxicity rather than supplementation. Given the absence of human clinical trials, randomized controlled studies, or even broader animal research focused on digestive benefit, the current body of evidence is insufficient to draw meaningful conclusions about black walnut as a digestive health supplement.