The aim of the present study was to evaluate the effect of increasing supplements of citric acid (CTA) on the in vitro availability of mineral (Ca, Mg), trace elements (Mn, Zn) and heavy metals (Pb, Cd). Phytaterich diets (0.8%) based on maize, soybean meal, corn starch and soybean oil (containing 5.0 g Ca, 1.2 g Mg, 50 mg Mn, 22 mg Zn, 10 mg Pb and 5 mg Cd per kg diet) were supplemented with 0, 1, 2, 3 and 4% of CTA. All diets were treated in a multi-enzyme in vitro system followed by equilibrium dialysis after peptic and pancreatic digestion. Under the conditions investigated, dietary addition of CTA enhanced dialysability of calcium, magnesium, manganese and zinc. Furthermore, a dose-dependent increase of lead and cadmium dialysability due to CTA supplementations was evident.