Modification of the membrane fatty acids affects the structure of the
surrounding environment causing a variation in membrane stability, flu
idity and permeability. In this study we developed a red blood cells f
ragility measurement to evaluate the influence of antioxidant intake o
n membrane functionality. Rats were fed diets differing in oxidized (p
eroxide value 400 mEq/kg fat) and antioxidant (vitamin E 7.8mg/kg diet
) compounds. The results indicate that the resistance of red blood cel
ls to the oxidative stress test was related to the tocophenols present
in diets. The main effect on red blood cells fragility was due to the
tocophenols which produced the greatest antioxidant response. The flu
idity and resistance of red blood cell membranes were determined by th
eir lipid and antioxidant composition. The higher the antioxidant, the
more efficient the red blood cell resistance.