The Mediterranean diet has been associated with increased longevity, improved quality of life, and a lower incidence of cardiovascular disease (CVD). Dietary patterns are well-known modulators of cardiovascular disease. Many studies have generated interest in identifying the nutrients involved in the protection against CVD and its underlying cause, atherosclerosis.

There has been a growing focus on a family of compounds called the Polyphenols. Polyphenols are a class of phytochemicals found in plants that give them their characteristic colors, and among other things, can provide chemical defense for the plant against certain environmental stresses. For example, the polyphenol anthocyanin gives grapes their purple color and the well-known polyphenol resveratrol protects them against fungal diseases and sun damage. There are more 4000 different known types of polyphenols. Polyphenols can often be noticed in foods because they can add astringency and bite to the flavor.

Many effects of polyphenols are known on the human body, including decreasing reactive oxygen species (ROS) and the modulation of gene expression, known as epigenetics. This continues to be an area of intense research. The Prevención con Dieta Mediterránea (PREDIMED) study was the largest prospective randomized controlled experiment ever conducted examining the effects of a Mediterranean style diet. Analysis of the data from this trial showed that in people with elevated cardiovascular disease (CVD) risk and those reporting a high polyphenol intake, a reduction in mortality was found.

An excellent comprehensive database on polyphenol content in foods is Phenol-Explorer.

A more in-depth presentation on epigenetics