By following a special diet almost completely lacking in the B vitamin folate, Victor Herbert (1927-2002) demonstrated during a 5-month study in 1961-1962 that a deficiency of this B vitamin leads to a particular kind of anemia called megaloblastic anemia.
Herbert was a 34 year old hematologist working under William Castle at the Thorndike Memorial Laboratory in Boston. At the time it was believed that a deficiency of folate alone wouldn’t cause disease. But Herbert suspected otherwise based on patients he had treated.
For nearly six months, Herbert ate a diet of meat, rice, potatoes, egg whites, coffee, and gelatin. Nothing fresh or uncooked. Anything that might have folate in it was boiled to destroy the vitamin, leaving only about 5 micrograms of folate in his daily food (400 micrograms a day is the usual recommendation).
After about a month, Herbert’s folate reserves in his body fell. During the fourth month, he became forgetful and had trouble sleeping. During the fifth month, he became irritable and, when anemia was diagnosed, the experiment was ended.