A glass of pomegranate juice (PG) a day may keep the cardiologist away, according to a new study in mice, in which Italian and American scientists demonstrated that mice drinking the juice had significantly reduced atherosclerosis.

Atherosclerosis, or hardening of the arteries, results when oxidative stress causes damage to the artery endothelium, leading to a buildup of fatty deposits, cholesterol, calcium and other substances on the artery wall. As these lesions, or plaques, grow they impede blood flow; a ruptured plaque can cause a blood clot that can result in a heart attack or stroke, depending on the site of the rupture. A diet high in antioxidant-rich fruits and vegetables may retard the development and progression of atherosclerosis.

The pomegranate (Punica granatum) is a peculiar-looking fruit, characterized by hundreds of seeds, each surrounded by juicy flesh. The fruit, which the ancient Chinese associated with longevity, has had a surge in popularity due in part to the availability of its vitamin- and antioxidant-rich juice in grocery stores. Until now, the artery-protecting effects of PG had remained untested.

Now, in the 29 March issue of the Proceedings of the National Academy of Sciences USA, a group led by Claudio Napoli of the University of Naples (Italy) provides evidence that regular consumption of PG can indeed have a role in preventing and treating atherosclerotic lesions. The group tested the preventive and therapeutic effects of PG in male hypercholesterolemic low-density-lipoprotein receptor-deficient (LDLR−/−) mice fed a high-cholesterol diet. They allowed one group of mice to develop plaques and then put them on the PG regimen; they fed the other group PG beginning at a young age. In both groups, atherosclerotic lesions were ∼20% smaller in the PG-treated mice as compared with controls.

Napoli's group also tested the effects of PG supplementation on cultured human coronary artery endothelial cells that were exposed to high levels of shear stress and found that the PG-treated cells produced significantly more artery-protecting nitric oxide (NO) than controls. As research team member Lou Ignarro of UCLA explains, “[PG] works by protecting NO against destruction [by free radicals], thereby increasing the functional levels of NO in the arteries. This leads to lower blood pressure and prevention of atherosclerosis.”

The next step in this work, Ignarro tells Lab Animal, is to “conduct a clinical trial in humans to determine if daily consumption of pomegranate juice can reduce the severity of atherosclerosis by improving blood flow and reducing the plaque buildup in the affected arteries.”