May Mellanby, née Tweedy (1882 – 5 March 1978) was an English medical researcher, styled Lady Mellanby after her husband, Edward Mellanby, was knighted in 1937. As well as nutrition research carried out with her husband, she conducted independent research into the physiology of dentition and the causes of dental disease.[1] She recommended a diet high in Vitamin D and low in cereals to help teeth protect themselves against decay.[2]