Lithiation of white button mushrooms (Agaricus bisporus) using lithium-fortified substrate: effect of fortification levels on Li uptake and on other trace elements.

High doses of lithium salts are used for the treatment or prevention of episodes of mania in bipolar disorder, but the medication is rapidly excreted and also shows side effects. Li may also be beneficial in people with mood disorders. Nutritionally, popular foods such as wild and cultivated mushrooms have low Li contents. This study evaluated the Li enrichment of white Agaricus bisporus mushrooms using Li2CO3 solutions to fortify the commercial growing substrate at various concentrations from 1.0 to 500 mg kg-1 dry weight (dw). Fortification of up to 100 mg kg-1 dw resulted in a significant (p < 0.01) dose-dependent increase in the accumulation of Li in mushroom, but the highest fortification level was found to be detrimental to fruitification. The median values of Li in fortified mushrooms corresponded to the fortification levels, increasing from 0.49 to 17 mg kg-1 dw relative to the background concentration of 0.056 mg kg-1 dw (control substrate contained 0.10 mg kg-1 dw). The potential for Li uptake in fruiting bodies was found to decrease at higher levels of fortification, with saturation occurring at 100 mg kg-1. Resulting lithiated mushrooms were up to 300-fold richer in Li content than specimens grown on control substrate. The fortification showed some effects on the uptake of other trace minerals, but concentrations of co-accumulated Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Pb, Rb, Sr, Tl, U, V and Zn were similar or lower than values reported in the literature for commercial A. bisporus. These lithiated mushrooms could be considered as a pro-medicinal alternative to treatments that use Li salts.