Minnich was born on January 24, 1910 in Zainesville, Ohio. She graduated from the University of Ohio with a BSc in home economics in 1937. In 1938, she received her master’s degree in nutrition from Iowa State College. In 1939, she started working as a technician in the hematology laboratory of Washington University in St. Louis. In 1958, she became a research professor at the same university. As a Fulbright grantee in the 1964-65 academic year, she conducted research on thalassemia and abnormal hemoglobins in Central Turkey, as well as iron deficiency, at Ankara University Medical School’s Pediatric Diseases and Health Clinic. In 1965, alongside Dr. Ayten Arcasoy, led a pediatric hematology laboratory, where she noticed a form of pica (eating non-food substance such as soil) involving clay eating. As a result of her research, which commenced through her Fulbright grant, she later discovered that clay contributes to iron deficiency. Minnich passed away in 1996.