Red grapes are also high in other antioxidants called polyphenols that prevent cell damage from free radicals.

BBC: Cabernet 'best for the heart'

Other studies have suggested that the polyphenols in red wine are responsible for its supposed benefits to health.

BBC: Glass of red wine

Previous studies have suggested that the polyphenols in red wine may help to cut inflammation, and possibly the risk of both cancer and heart disease.

BBC: NEWS | Health | Wine 'can help treat gum disease'

The researchers said that extra-virgin olive oil was used in the study because it contains more polyphenols, which have been shown to improve cholesterol levels, than refined olive oil.

WSJ: Mediterranean Diet of Olive Oil, Nuts, Reduces Heart Disease, Study Finds

Small molecules in nature, mostly what are called polyphenols (resveratrol, quercetin, catechin, curcumin, others), as found in concentrated form in red wine, can cross the cell wall and enter the cell and influence genetic machinery.

FORBES: Is Ethical Human Genetic Enhancement Possible?

Olive oil is also a rich source of potent antioxidants called polyphenols, which may help slow the progression of atherosclerosis (narrowing of the arteries because of cholesterol and inflammatory cell accumulation) by decreasing the susceptibility of bad cholesterol to oxidative damage and stress.

CNN: How heart-healthy is olive oil?