Pomegranates and the heart

What are pomegranates?

Pomegranates are exotic in America but commonplace in the Middle East. They are the fruit of the Punica granatum tree, which is native to Iran and is also cultivated in some Mediterranean countries and in parts of Russia, Afghanistan, India, China, and Japan.

Pomegranates are relatively new to Americans, but they have a venerable history. Legend holds that they grew in the Garden of Eden, and they have a place in the mythology and traditions of ancient Greece, Persia, Babylonia, and China.

The edible portion of a pomegranate is composed of 80% fruit and 20% seeds. Like other foods, the pomegranate contains hundreds of chemicals. Unlike many other foods, though, some of the pomegranate's chemicals have strong biological actions and potential medical benefits. The fruit is 85% water and 10% sugar "" but it also contains large amounts of vitamin C and a variety of polyphenols and tannins, which have potent antioxidant activities. The seeds contain fiber, a steroid estrogen, estrone, and isoflavones, including two (genistein and daidzein) that are abundant in soy. The seeds also contain a unique oil that contains an uncommon fatty acid, punicic acid.

Pomegranates and the heart

Preliminary results in test tubes, animals, and humans suggest that pomegranates may have beneficial effects on cardiovascular disease. Studies in mice and men show that drinking pomegranate juice can protect LDL ("bad") cholesterol from oxidative damage. In addition, pomegranate juice slows the progression of plaques in mice with atherosclerosis.

Two small clinical studies are even more intriguing. Doctors in Israel studied 19 patients with atherosclerotic narrowing of their carotid arteries. All the volunteers received the best conventional medical treatments; 10 also received a daily dose of pomegranate juice. After a year, the carotid artery thickness had increased by 9% in the conventionally treated patients but had decreased in the pomegranate group. Blood pressure also fell significantly during pomegranate treatment; no side effects were reported.

The Israeli study was not a randomized trial, but a 2005 American study randomly assigned 45 patients with coronary artery disease to receive pomegranate juice or a placebo in addition to their normal clinical care. Stress tests with nuclear scans were performed at the start of the study and after three months; the patients who drank 8 ounces of commercially available pomegranate juice a day enjoyed improved cardiac blood flow.