Final answer:
In the 1800s, many people were likely locked up in mental institutions unknowingly due to a deficiency of Vitamin B12.
Step-by-step explanation:
In the 1800s, many people were likely locked up in mental institutions unknowingly due to a deficiency of Vitamin B12. Vitamin B12 deficiency can lead to a condition called pernicious anemia, which can cause symptoms such as fatigue, memory problems, and psychiatric disorders. It is important to eat foods that contain Vitamin B12, such as meat, fish, and dairy products, to prevent this deficiency.