Heart disease patients who eat one grapefruit daily can significantly reduce the levels of cholesterol in their blood in comparison to patients who do not eat the fruit, a new study has found. Chronic high blood cholesterol is a major risk factor for heart disease.

The study was conducted by a group of scientists under the leadership of Dr. Shela Gorinstein of the Hebrew University School of Pharmacy, Department of Medicinal Chemistry and Natural Products, in cooperation with Prof. Abraham Caspi, head of the Institute of Cardiology at Kaplan Hospital in Rehovot. In addition, scientists from Poland and Singapore participated in laboratory work connected with the project.

The study, which strengthens a growing body of evidence supporting the heart benefits of eating citrus fruit, was published this month on the website of the American Chemical Society’s Journal of Agricultural and Food Chemistry. The study will appear in the journal’s March 22 print issue.

February has been designated in the U.S. as American Heart Month. In the U.S., heart disease is the number one killer of women.

The grapefruit study included 57 patients at Kaplan Hospital, both men and women, with hyperlipidemia (high blood cholesterol) who recently had coronary bypass surgery and did not take statin drugs during the study period. Statins are commonly prescribed to lower cholesterol.

The patients, equally divided into three treatment groups, were given either a single serving of fresh red grapefruit, white (blond) grapefruit or no grapefruit, along with regular, balanced meals for 30 consecutive days. Israeli Jaffa red Star Ruby and white grapefruit varieties were used in this study.

The patients who received either red or white grapefruit showed significant decreases in blood lipid levels, whereas the patients that did not eat grapefruit showed no changes in lipid levels, according to the researchers. Red grapefruit was more effective than white in lowering lipids, particularly blood triglycerides, a type of cholesterol whose elevated levels are often associated with heart problems, the researchers say.

Grapefruit has an antioxidant action that provides a beneficial health benefit, says Dr. Gorinstein, adding that the red variety generally has a higher level of antioxidants than the white. But it’s also possible that red grapefruit may contain currently unknown chemicals that are responsible for the observed triglyceride-lowering effect, she says. Additional studies are planned.

Both the fresh fruit and the juice are believed to be equally beneficial, Dr. Gorinstein and her associates say. One cup of fresh grapefruit is roughly equivalent to half a cup of juice.

Grapefruit is known to interact with certain medications - sometimes adversely - so the researchers caution people on prescription medication to consult with their doctor or pharmacist to determine whether their medicine will interact before consuming grapefruit products.

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