We’ve updated our article on White Blood Cells in Vegans.
We added a cross-sectional study that found that vegans had significantly lower white blood cell counts than nonvegetarians, though usually within the normal range (Tong, 2019). We also added a randomized controlled trial that resulted in significantly decreased white blood cell count after putting nonvegetarians on a vegan diet for 4 weeks (Lederer, 2020).
We listed five hypotheses about why vegans might have lower white blood cell counts; however, it’s important to note that none of these hypotheses have been well-studied or proven. So for now, we cannot say with any certainty why vegans tend to have lower white blood cell counts.