Natto

Natto — fermented whole soybeans made using Bacillus subtilis var. natto — is the most divisive food on this list and the one with the most remarkable specific health evidence. The texture (extremely sticky, with strings extending from the beans when stirred) and the flavor (strong, ammonia-adjacent, fermented) make it challenging for uninitiated Western palates. The clinical evidence that overrides the taste barrier: natto is the single richest food source of Vitamin K2 (as MK-7 form) at 872 mcg per 100g serving — approximately 1,000x more than cheese, the next highest source. MK-7 has a plasma half-life of 72 hours (vs 1-2 hours for K1), meaning natto consumed several times weekly maintains protective K2 plasma levels throughout the week. Epidemiological data from Japan finds natto consumption associated with the lowest cardiovascular mortality in the Japanese cohort. The Japanese traditional serving: over rice with soy sauce and mustard.