Cranberries are a particularly rich source of phenolic acids and polyphenols, particularly flavonoids. Among the 20 most commonly consumed fruits in the American diet, cranberries have the highest total phenol content. Health benefits attributed to cranberries include the prevention of urinary tract infections and stomach ulcers as well as improved oral hygiene. These benefits appear to be due principally to the ability of cranberries to interfere with the adhesion of some bacteria to select cell types and surfaces.
Cranberries and cranberry constituents, including several phenolic and polyphenolic compounds, have also been shown to possess antibacterial, antiviral, anti-mutagenic, anti-carcinogenic, anti-tumorigenic, anti-angiogenic, and antioxidant activities. Most of this evidence is derived from in vitro studies and animal models. The limited number of human studies available indicate these phytochemicals are bioavailable and bioactive. However, more information is required on the bioavailability and metabolism of cranberry polyphenols, as well as on the relationship between cranberry dose and duration of use, to better understand their impact on risk factors for chronic diseases.
