• As a test of the significance of previously described biochemical abnormalities in thiamine-dependent enzymes in brains and other tissues in patients with Alzheimer's disease, a double-blind, placebo-controlled, crossover, outpatient pilot study compared the effects of 3 g/d of oral thiamine hydrochloride for three months with those of a niacinamide placebo. Eleven moderately impaired patients with "probable Alzheimer's disease" by the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria completed the study. All patients were well nourished and had no stigmata of dietary thiamine deficiency. Their initial mean ± SEM Mini-Mental State Examination score was 14.2 ± 1.4, and the mean age was 72 years. Global cognitive rating by the Mini-Mental State Examination was higher during three months with 3 g/d of oral thiamine hydrochloride than with niacinamide placebo. Behavioral ratings, however, did not differ significantly, nor did clinical state when it was judged subjectively.
Blass JP, Gleason P, Brush D, DiPonte P, Thaler H. Thiamine and Alzheimer's DiseaseA Pilot Study. Arch Neurol. 1988;45(8):833–835. doi:10.1001/archneur.1988.00520320019008