Animal Models of Niacin-Nicotinamide Deficiency

The human disease caused by niacin (vitamin B₃ ) deficiency is pellagra, a disease that at one time filled insane asylums all over the world before the function of niacin was discovered. The recognition of pellagra as an endemic disease in the US dates from Searcy’s report in 1907 (Strandell et al., 1989 ) describing 88 cases of dementia in the Mount Vernon, Alabama Insane Asylum. Extensive knowledge about the course of pellagra has since been obtained and this disease has been eradicated as a public health problem; however, exact relationships between niacin deficiency and specific lesions in the central nervous system (CNS) remain poorly defined. Other nutritional deficiencies, common among patients in mental hospitals and in those with senility (Gregory, 1955 ; Hersov, 1955; McIlwain, 1966 ), undoubtedly contribute to neuronal dysfunction and exacerbate neurological problems associated with niacin deficiency. Mental symptoms associated with niacin deficiency often precede the dermatitis and other effects of this nutritional deficiency, suggesting a special sensitivity of the nervous system. If initial mental disturbances are not remedied by administration of nicotinic acid or tryptophan, from which nicotinic acid is synthesized in vivo, permanent structural changes occur in cerebral tissue.