After working as a research student from 1905 to 1907, Mellanby studied medicine at St. Thomas's Hospital in London, and in 1913 became a medical doctor. He served as a lecturer at King's College for Women in London from 1913 to 1920, during which time he was asked to investigate the cause of rickets. He discovered that feeding caged dogs on a diet of porridge induced rickets, which could then be cured with cod liver oil and concluded that rickets was caused by a dietary factor. It was later discovered that the actual cause of rickets is lack of vitamin D due to lack of sunlight which can be prevented or remedied by ingesting food rich in vitamin D, such as cod liver oil.
He worked on the detrimental effect of foods containing significant phytic acid, particularly cereals.[11]
In 1914 he married May Tweedy, a lecturer at Bedford College (London) who would also carry out research into nutrition and dental disease.[12]
In 1920 he was appointed professor of pharmacology at the University of Sheffield, and consultant physician at the Royal Infirmary in that city. He then served as the secretary of the Medical Research Council from 1933 to 1949.
He was elected a Fellow of the Royal Society in 1925.[1][13][14] He was awarded their Royal Medal in 1932 and their Buchanan Medal in 1947.
In 1932, Mellanby was awarded the Cameron Prize for Therapeutics of the University of Edinburgh. He delivered the Croonian Lecture to the Royal College of Physicians in 1933 and the Croonian lecture to the Royal Society in 1943, both on the subject of diet.
He was knighted (KCB) in the 1937 Coronation Honours[15] and made GBE in the 1948 New Year Honours.[16] He was appointed an Honorary Physician to the King in 1937.[17]
