Natto for Blood Clotting

Research suggests that natto and its derived compounds may influence blood clotting through two primary mechanisms: the enzyme nattokinase and the vitamin K2 form known as menaquinone-7 (MK-7). One small open-label randomized controlled trial found that nattokinase supplementation over two months was associated with meaningful reductions in fibrinogen, factor VII, and factor VIII — proteins central to the clotting cascade — across healthy individuals and those with cardiovascular or kidney conditions, suggesting a potential fibrinolytic effect. The remaining studies in this set are process-oriented laboratory investigations focused on optimizing industrial MK-7 production by Bacillus natto under varying nutrient and oxygen conditions, and while they do not directly address blood clotting outcomes in humans, they provide relevant context for understanding how natto-derived compounds are produced. Overall, the direct human evidence is limited to a single trial without a placebo control group, meaning findings should be interpreted cautiously, and more rigorous controlled research is needed before firm conclusions can be drawn about natto's role in modulating blood clotting.