That was actually a problem for the Japanese Navy, where crewmen (and particularly officers) suffered from beriberi, a deficiency of B1/thiamine. Many of them,

That was actually a problem for the Japanese Navy, where crewmen (and particularly officers) suffered from beriberi, a deficiency of B1/thiamine. Many of them, having "made it" socioeconomically, focused on white rice to the exclusion of "lower class" options.