The effect of fasting on the parameters of the antioxidant defence system in the blood of vegetarian human subjects.

OBJECTIVES

Although the evidence is strong that fasting has anti-tumor, anti-inflammatory and anti-ageing actions, the mechanisms responsible for these phenomena are still unclear. An ameliorated antioxidative defence with fasting may be the cause of such effects. The objective of the present work was to determine the influence of fasting on antioxidant systems in healthy young vegetarian humans.

DESIGN AND METHODS

We measured Trolox Equivalents Antioxidant Capacity (TEAC) of plasma, erythrocytes superoxide dismutase (SOD) activity, blood glutathione peroxidase (GPx) activity, level of total blood non-proteic thiols (TBNT), plasma ceruloplasmin activity, plasma level of NO metabolites (the sum of nitrites and nitrates, NOx), in 18 healthy young humans (age 20-27 years) after 12h (overnight fasting) and 80h of fasting.

RESULTS

Trolox Equivalents Antioxidant Capacity of plasma, the level of total blood nonproteic thiols, plasma ceruloplasmin activity and plasma concentration of nitrites and nitrates were significantly increased after 80h of fasting. Superoxide dismutase activity and glutathione peroxidase activity were lower after 80h of fasting.

CONCLUSIONS

Our results suggest that fasting induces the "reorganisation" of antioxidative defence lines: fasting increases especially plasma protective systems (total antioxidant capacity of plasma, plasma ceruloplasmin activity) and decreases an erythrocytes antioxidant enyzme (superoxide dismutase) and blood glutathione peroxidase.