Effect of nutritional supplement therapies in the prevention of Alzheimer's disease in a transgenic mouse model

Background/Aims: The aim of this study was to examine the efficacy of diets containing (-)-epigallocatechin-3-gallate (EGCG), curcumin (Curc), DHA and a-lipoic acid (ALA) on reducing cognitive deficits and brain betaamyloid (Ab) levels in a transgenic Alzheimer’s disease (AD) mouse model.

Methods: Sixty mice (age six months) were randomly assigned to one of six nutritional supplement groups (Control, Curc, Curc+EGCG+ALA, Curc+DHA+ALA, EGCG+DHA+ALA, Curc+EGCG+DHA+ALA) for 12 months. At 18 months of age, the cognitive effects of the nutritional supplements were evaluated behaviourally using the cued and contextual fear avoidance test. A commercially available assay was used for the detection and measurement of Ab levels in the brain. Difference between groups was tested using one-way ANOVA.

Results: All nutritional supplement groups had lower frontal cortex Ab42 levels compared to Controls (p < 0.05). Only the DHA+EGCG+ALA group had reduced frontal cortex Ab40 levels compared to Controls (p < 0.05). No differences were observed in cerebellum Ab42 levels, although the Curc+EGCG+ALA and DHA+EGCG+ALA groups did have lower cerebellum Ab40 levels compared to Controls (p < 0.05). All nutritional supplement combination groups had significant increases in time spent freezing in the context, altered context and auditory cue conditions in the cued and contextual fear avoidance testing compared to Controls (p < 0.05).

Conclusions: The combination nutritional supplements in this study were effective at lowering brain Ab42 levels and improving cognition. However there does not appear to be additional benefits from combinations of these nutritional components over a single nutritional supplement of Curc.