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Eating grapefruit (especially the red variety) or drinking its juice daily can significantly minimize "bad cholesterol" (low-density lipoprotein or LDL) and triglycerides that are major factors in cardiovascular disease, according to a study published in an online edition of the American Chemical Society's Journal of Agricultural and Food Chemistry.
The study, due to appear in the journal's March 22 print edition, was conducted by a group of researchers headed by Dr. Shela Gorinstein of the Hebrew University School of Pharmacy's Department of Medicinal Chemistry and Natural Products, and in cooperation with Prof. Abraham Caspi, head of the Cardiology Institute at Rehovot's Kaplan Medical Center. Scientists from Poland and Singapore also took part in the project as participants in lab work.
To test the benefits of consuming grapefruit, Gorinstein tested 57 patients at Kaplan who were suffering from hyperlipidemia (high levels of LDL) and had recently undergone coronary bypass surgery. None of them took statin drugs - commonly prescribed medications that lower cholesterol but in some patients can have harmful side effects.
The group was equally divided into three sub-groups. For 30 consecutive days, one group received a daily single serving of fresh red grapefruit (Jaffa red Star Ruby); a second received white (Jaffa blond) grapefruit; and a third - the control group - received none. All the participants ate balanced meals over the course of the month.
The patients who received either red or white grapefruit showed significant decreases in blood lipid levels, while the patients that did not eat grapefruit showed no changes in lipid levels. In addition, red grapefruit was found to be more effective than white in lowering lipids, particularly triglycerides - a type of blood fat whose elevated levels are often associated with heart problems.
Red grapefruit consumption reduced total cholesterol by 15.5 percent and white grapefruits by 7.6%; the red cut LDL by 20.3% and the white by 10.7%; and the red reduced triglycerides by 17% and the white by 5.6%, compared to no change in the control group.
Grapefruits contain antioxidants, Gorinstein said, noting that the red variety generally has a higher level of antioxidants than the white. It's possible that red grapefruit may contain currently unknown chemicals that are responsible for the observed triglyceride-lowering effect, she added.
Fresh grapefruit and its juice are believed to be equally beneficial, Gorinstein and her associates said. One cup of fresh grapefruit is roughly equivalent to half a cup of juice.
The researchers cautioned that grapefruit is known to interact with certain medications - sometimes adversely - and advised people on prescription medication to consult with their doctors or pharmacists before consuming grapefruit products. A delay of several hours between eating grapefruit or drinking its juice and taking medications can eliminate the problem.
In December, Gorinstein, who immigrated from Russia more than three decades ago, received the Cavalier Cross of the Polish Order of Merit, becoming the first Israeli ever to receive this Polish government honor. Gorinstein, who has achieved renown for her many research projects on the health benefits of various beverages and fruits, has worked closely with a number of Polish researchers.
She recently published a clinical study showing that eating Jaffa Sweeties (pomelit) also reduces blood cholesterol and the risk of heart disease, but found that grapefruit is more effective. Additional studies are planned.