With Chittenden, Mendel became one of the founders of the science of nutrition. Together with longtime collaborator Thomas B. Osborne he established essential amino acids. As early as 1910 he found an important growth factor...later to be known as vitamin B. In 1903, at age 31, he was appointed full professor of physiological chemistry. In promoting Mendel, Yale made him one of the first high-ranking Jewish professors in the United States. Capping his illustrious career Mendel was appointed Sterling Professor of Physiological Chemistry in 1921. Of the twenty professors to be designated Sterling professors in the decade following their inception in 1920, only two were selected before Mendel. Of the twenty, Mendel was the only Jew.