Recently, a growing interest has been recorded in mineral content of mammalian diet, which might impair their development. Focused on the topic, we studied the effect of Al3+, Si4+, Sr2+ and Na2S on the intensity of malondialdehyde (MDA) production in vitro. MDA, as one of oxidative stress markers, was determined in rat brain homogenates in the conditions of lipid peroxidation (LP) activated by iron ions and ascorbate. Our results showed a significant increase in lipid peroxidation after addition of aluminium ions. We assume a probable impact of Al3+ on active or regulatory centres of antioxidant enzymes, resulting in the reduction of their antioxidant functions. The addition to Si4+ or Na2S to samples with Al3+ significantly decreased Fe2+-activated LP. We can explain the influence of Na2S by the formation of insoluble complexes with iron. Similarly, the effect of Si4+ can be related to the production of aluminium-silicon complexes. In our view, an optimal ratio of aluminium and silicon ions (or aluminium ions and Na2S) in the diet might have beneficial effects on brain functions.