Final answer:
Thiamin, or vitamin B₁, is the vitamin responsible for preventing beriberi, a condition that historically affected populations consuming diets deficient in thiamin-rich foods like unpolished rice.
Step-by-step explanation:
The vitamin responsible for preventing beriberi is thiamin, also known as vitamin B₁. Beriberi is a disease that affects the nerves, heart, and gut, and is caused by a deficiency of thiamin. Thiamin is considered a water-soluble vitamin and plays a crucial role in the chemical reactions for producing energy from food.
It was historically discovered that beriberi was endemic in East Asia among people consuming polished white rice, lacking in thiamin. This condition was mitigated when the diet was changed to include unpolished rice, which retains more thiamin content. In history, Takaki Kanehiro, Christiaan Eijkman, and Casimir Funk played significant roles in identifying the importance of thiamin in the diet and its role in preventing beriberi.