Beriberi was mostly caused by the replacement of whole rice by white rice. White rice is not a whole grain and has most of its fiber and many nutrients removed. If they had eaten whole rice instead, the disease is then easily prevented.

But eating whole rice was apparently not socially well seen, as it was a food associated with the very poor.

Later some of the nutrients have been sprayed back into the white rice, with the recommendation to not wash the rice before cooking, not to wash away the nutrients.