Thiamine and Alzheimer's disease. A pilot study.

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.