In the paper presented, the authors review the potential impact of selected nutrients on mental activity, as well as the risk of dysphoria, dementia, and depression to occur in people. Evidence was provided that the B-complex and antioxidant vitamins play an important role in the protection against unfavorable changes in blood-vessels, as well as against arteriosclerosis and dementia diseases. It was demonstrated that such substances as choline, alcohol, and caffeine are significantly involved in the functioning of the central nerve system, and that a diet influences the synthesis of ß-endorphin, which is a neuro-active substance.