Some of the proposed reasons are flatworm and hookworm infection, H. Pylori infection, gastrointestinal bleeding and their vitamin intake being disrupted by the incorporation of modern high-starch foods to the diet.

其中一些原因是扁虫和钩虫感染、幽门螺杆菌感染、胃肠道出血以及由于在饮食中加入现代高淀粉食物而中断了维生素的摄入。