The overall effect of brain zinc (Zn(2+)) in the progression and development of Alzheimer's disease (AD) is still not completely understood. Although an excess of Zn(2+) can exacerbate the pathological features of AD, a deficit of Zn(2+) intake has also been shown to increase the volume of amyloid plaques in AD transgenic mice. In this study, we investigated the effect of dietary Zn(2+) supplementation (30 p.p.m.) in a transgenic mouse model of AD, the 3xTg-AD, that expresses both beta amyloid (A beta)- and tau-dependent pathology. We found that Zn(2+) supplementation greatly delays hippocampal-dependent memory deficits and strongly reduces both A beta and tau pathology in the hippocampus. We also evaluated signs of mitochondrial dysfunction and found that Zn(2+) supplementation prevents the age-dependent respiratory deficits we observed in untreated 3xTg-AD mice. Finally, we found that Zn(2+) supplementation greatly increases the levels of brain-derived neurotrophic factor (BDNF) of treated 3xTg-AD mice. In summary, our data support the idea that controlling the brain Zn(2+) homeostasis may be beneficial in the treatment of AD. Cell Death and Disease (2010) 1, e91; doi: 10.1038/cddis.2010.73; published online 28 October 2010