Although much is known about pathogenesis of Alzheimer’s disease (AD), available evidence doesn’t explain everything and contiguous hypotheses such as “the brain trace metal dyshomeostasis” take place in order to enlighten the residual part of disease risk.
The aim of this systematic review is to evaluate the currently available studies concerning metal concentration in biological human matrices of AD subjects. All the studies meeting the eligibility criteria showed a large variability of outcomes. Therefore, although there is some evidence of a difference in metal concentration between AD and non-AD subjects, it should be interpreted with caution.
Moreover, because of the complex interaction between iron, copper and zinc, it could be worthwhile to focus on studies investigating Cu/Zn, Cu/Fe, and Zn/Fe ratios as possible biomarkers of this effect, instead of concentrating on measuring single metal levels in biological matrices, in particular those with a clear tendency to insignificant variations in AD subjects (e.g. chrome, molybdenum, nickel and tin).