A trial of thiamine in Alzheimer's disease

Because a previous short-term study demonstrated a statistically significant, but not clinically important, improvement in cognitive test scores during thiamine treatment in patients with dementia of the Alzheimer's type, a 12-month, double-blind, parallel-group study was conducted to examine whether long-term administration of thiamine at 3 g/d might slow the progression of dementia of the Alzheimer's type. Fifteen subjects were enrolled and 10 completed the 1-year study. Data are available for two additional subjects through the first 9 months of study. No significant differences were found between the placebo and thiamine groups at any point during the study. In both groups, overall means for the Mini-Mental State Examination, verbal learning, and naming scores decreased significantly over the 12-month study period. These results do not support the hypothesis that long-term administration of thiamine at 3 g/d might slow the progression of dementia of the Alzheimer's type.