Olive Oil Fights DNA Oxidation

NUTHETAL, Germany--Western European scientists investigated the ability of the Mediterranean diet to protect DNA against oxidative damage and to reduce cancer incidence, focusing on olive oil and its phenolic content. Results of their trial, published in the FASEB Journal (Epub online before print, Nov. 16, 2006), showed olive oil reduces DNA oxidation, and increased olive oil consumption may contribute to reduced cancer rates.

In the multicenter, double-blind, randomized, controlled crossover, intervention trial, researchers investigated the effect of olive oil phenolic content on urinary oxidation products of guanine (8-oxo-guanine, 8-oxo-guanosine and 8-oxo-deoxyguanosine). They administered 25 ml/d of three olive oils with low, medium, and high phenolic content to healthy males (n=182) for two weeks.

At baseline, urinary excretion of 8-oxo-guanosine (RNA oxidation) and 8-oxo-deoxyguanosine (DNA oxidation) was higher in the Northern regions of Europe compared with Central and Southern European regions. There were no differences in urinary excretions of these compounds following the three olive oil interventions. However, according to researchers, testing the effect of oil from urinary 8-oxo-deoxyguanosine (DNA oxidation) changes from baseline to post-treatment showed a reduction of DNA oxidation by 13 percent, supporting the theory that ingestion of olive oil is beneficial and can reduce the rate of oxidation of DNA. They also noted the beneficial effect on DNA oxidation did not correlate to the phenolic content of the olive oil. They further concluded higher DNA and RNA oxidation in Northern European regions compared with that in the Central and Southern regions supports the contention that olive oil consumption may explain some of the North-South differences in cancer incidences in Europe.