Reviewed: Sumner MD, Elliott-Eller M, Weidner G, et al. Effects of pomegranate juice consumption on myocardial perfusion in patients with coronary heart disease. Am J Cardiol. 2005;96:810-814.

Pomegranate (Punica granatum L., Punicaceae) juice is a rich source of antioxidants, such as soluble polyphenols, tannins, and anthocyanins, and it may have antiatherosclerotic properties. Animal studies have shown that dietary supplementation with polyphenolic antioxidants inhibits the oxidation of low-density lipoprotein (LDL, the "bad" cholesterol) and macrophage foam cell formation, and thus retards the development of atherosclerosis (the accumulation of plaque on arterial walls, which can increase the risk of cardiovascular problems such as heart attack, stroke, etc.). However, the effects of pomegranate juice in patients with ischemic coronary heart disease (CHD) have not been investigated. (CHD is characterized by reduced blood supply from blocked coronary arteries, typically caused by atherosclerosis.) The objective of this study was to evaluate the effects of pomegranate juice on myocardial perfusion (a test that uses low doses of radioactive agents to evaluate the heartÕs blood flow and function) in patients with CHD.

Forty-five patients (age range: 69 ± 10) with stable CHD were enrolled in this randomized, placebo-controlled, double-blind study conducted by researchers at the University of California at San Francisco (UCSF), the California Pacific Medical Center (San Francisco, CA), and the Preventative Medicine Research Institute (PMRI, Sausalito, CA). All patients were confirmed to have stress-induced ischemia evidenced by at least one reversible myocardial perfusion. The patients were randomly assigned to receive either 240 mL/day (8 oz) of pomegranate juice (POM Wonderful, Los Angeles, CA) or a modified sports beverage similar to the pomegranate juice in taste, color, and caloric content (placebo) for 3 months. (The placebo did not contain any juice or fruit or bioactive compounds. It contained several flavors of Gatorade¨ [PepsiCo, Purchase, NY] with added corn syrup to make it isocaloric with the pomegranate juice. The placebo was tested in an independent laboratory for polyphenols, and it was determined that it contained none.) Blood pressure and lipid, glucose, and hemoglobin A1c concentrations were measured at baseline and at 3 months. Additionally, the subjects underwent myocardial perfusion imaging at rest and under stress with the use of single-isotope (technetium-99m tetrofosmin) single-photon emission computed tomography at baseline and at 3 months. Technetium uptake was measured in 17 myocardial segments per subject with a semiquantitative 5-point scoring method, where 0 = normal uptake and 4 = absent uptake. A summed difference score (SDS), indicating the difference in blood flow under resting and stressed conditions was derived to indicate the level of inducible myocardial ischemia.

Inducible ischemia, determined on the basis of SDSs, was not significantly different between the pomegranate and placebo groups at baseline; however, it decreased in the pomegranate group (by 0.8 plus/minus 2.7) and increased in the placebo group (by 1.2 plus/minus 3.1) at 3 months (P < 0.05). This benefit was observed with no significant changes in cardiac medications or revascularization in either group. No significant changes in body weight, blood pressure, or plasma lipid, glucose, or hemoglobin A1c concentrations were observed throughout the study. Episodes of angina decreased by 50% (from 0.26 to 0.13) in the pomegranate group but increased by 38% (from 0.53 to 0.75) in the placebo group, though this difference was not statistically significant.

The results suggest, for the first time, "that daily consumption of pomegranate juice for 3 months may decrease myocardial ischemia and improve myocardial perfusion in patients who have ischemic CHD as measured by the SDS." The clinical significance of this finding was supported by the average improvement in myocardial perfusion of 17% in the pomegranate group and the average worsening in myocardial perfusion of 18% in the placebo group. These findings are consistent with the beneficial effects of polyphenol-containing beverages observed by other investigators. In a recent study conducted by de Nigris et al,¹ oral administration of pomegranate juice to mice at various stages of hypercholesterolemia reduced the progression of atherosclerosis significantly. The authors of the current study recommend that additional studies be conducted to determine the effects of pomegranate juice in a larger sample size and over a longer period of time.

—Brenda Milot, ELS

Reference

1. de Nigris F, Williams-Ignarro S, Lerman LO, et al. Beneficial effects of pomegranate juice on oxidation-sensitive genes and endothelial nitric oxide synthase activity at sites of perturbed shear stress. Proc Natl Acad Sci [serial online]. 2005;102(12):4217?4655. Available at: www.pnas.org/cgi/content/abstract/0500998102v1. Accessed September 22, 2005.