Fortifying olive oil with epigallocatechin 3-gallate (EGCG), however, did not produce any additional benefits, report researchers.
“The current study demonstrates that longer-term supplementation of olive oil improves endothelial function in individuals with low to intermediate cardiovascular risk, an effect likely attributed to reduction in vascular inflammation,” they wrote in the European Journal of Nutrition.
“This is the first such demonstration of such a permanent endothelial benefit via long-term supplementation of a macronutrient.”
Researchers from the Mayo Clinic and College of Medicine and Dipartimento di Scienze Farmaceutiche in Florence investigated the effects of olive oil supplementation (30 mL per day providing 340 mg/kg polyphenols), with or without added EGCG (providing a total of 600 mg/kg of polyphenols), on endothelial function – the cells lining the surface of the blood vessels.
Dysfunction of the endothelium is reported to be a predictor of future cardiovascular events in people with high risk of atherosclerosis and heart disease.
The participants all had atherosclerosis, meaning they already had endothelial dysfunction. Eighty-two people participated in the double-blind, randomized trial.
Fifty-two people completed the four month study and results showed that olive oil “significantly improved endothelial function”, with no significant differences between the groups.
Olive oil was also associated with a “significant reduction in inflammatory parameters”, said the researchers.
“Interestingly, patients with low endothelial function at baseline appear to garner the most benefit from olive oil,” they said.
“Thus, supplementation with olive oil seems a reasonably easy and relatively cheap dietary measure to improve the endothelial function and perhaps favorably alter the progression of atherosclerotic disease, particularly in patients with already markedly impaired endothelial function.”
Source: European Journal of Nutrition
Published online ahead of print, doi: 10.1007/s00394-012-0433-2
“Beneficial effects of polyphenol-rich olive oil in patients with early atherosclerosis”
Authors: R. J. Widmer, M. A. Freund, A. J. Flammer, J. Sexton, R. Lennon, A. Romani, N. Mulinacci, F. F. Vinceri, L. O. Lerman and A. Lerman