Hydroxytyrosol augments the redox status of high fat diet-fed rats
Hydroxytyrosol (HT) is being investigated for its manifold biological activities. In this study, we assessed whether HT could lessen the metabolic and redox imbalance caused by high-fat diet, in a rat model. Male Wistar rats were divided into four groups (n = 4 each), homogeneous for age and weight. Group 1: control diet; Group 2: control diet + 20 μg HT/d by oral gavage; Group 3: high fat, high carbohydrate diet; Group 4: high fat, high carbohydrate diet +20 μg HT/d by oral gavage. The experiment lasted four weeks. The addition of HT to the high fat diet did not slow down weight gain as compared to the unsupplemented diet. No significant differences in glycemia were observed among the four experimental groups. Ascorbic acid plasma concentrations at the end of the experimental period were non-significantly lower in high fat diet rats than in control animals. Plasma, but not erythrocytes hydroperoxide concentrations were significantly lower in group 4 animals as compared with the other ones. The high-fat diet induced protein carbonyl formation. Even though supplementation with HT lowered carbonyls’ concentrations, the effect did not reach statistical significance. Conversely, the action of HT became significant when plasma MDA was measured.HT also increased serum antioxidant capacity, assessed as ORAC of total serum and as conjugated diene formation of copper-oxidized isolated LDL/HDL.
Public heath bodies should actively discourage the adoption of obesogenic high-fat diets, but HT as supplement modulates some of their harmful effects.