Natto Consumption Suppresses Atherosclerotic Plaque Progression in LDL Receptor-Deficient Mice

This small mouse study tested whether different variants of natto — a fermented soybean product — affect atherosclerotic plaque development in a genetic model of high cholesterol.

Using LDL receptor-deficient mice with only six animals per group, the investigators found that high vitamin K2 natto reduced plaque lesion size, lowered circulating CCL2 (an inflammatory cytokine), and altered gut microbiota composition. The effect exceeded what vitamin K2 alone could explain, suggesting other natto constituents contribute.

The study is hypothesis-generating at best. Six mice per group is far below the sample size needed for reliable effect estimation, the LDL receptor-deficient model has significant limitations as a human analog, and gut microbiota findings in a controlled animal environment do not readily translate to humans. Human data on natto and atherosclerosis remains essentially absent.

We rate the evidence limited. An intriguing mechanistic signal in a very small animal study; it does not establish a clinical case for natto supplementation in humans.