Scurvy Campaign had a lack of vitamin C in their diet which caused many of the soldiers to contract scurvy. It is thought that scurvy is one of many reasons that the Allied attack on Gallipoli failed. Vilhjalmur Stefansson, an arctic explorer who had lived among the Inuit, proved that the all-meat diet they consumed did not lead to vitamin deficiencies. He participated in a study in New York's Bellevue Hospital in February 1928, where he and a companion ate only meat for a year while under close medical observation, yet remained in good health. In 1927, Hungarian biochemist Szent-Györgyi isolated
Vitamin D deficiency with primary hyperparathyroidism) or with hypoparathyroidism. Patients with chronic liver disease or intestinal malabsorption disorders may also require larger doses of vitamin D (up to 40,000 IU or 1 mg (1000 micrograms) daily). The estimated percentage of the population with a vitamin D deficiency varies based on the threshold used to define a deficiency. Recommendations for 25(OH)D serum levels vary across authorities, and probably vary based on factors like age; calculations for the epidemiology of vitamin D deficiency depend on the recommended level used. A 2011 Institute of Medicine (IOM) report set the sufficiency level at 20 ng/ml (50 nmol/l),