February 19, 2006, Updated July 2, 2014

A grapefruit a day – particularly the red variety – can help keep heart disease at bay, according to a new study by Israeli researchers. Heart disease is the number one killer of women in the United States, and February has been designated as American Heart Month.

The research team led by Hebrew University of Jerusalem Dr. Shela Gorinstein, found patients who ate the equivalent of one grapefruit a day had lower cholesterol levels than those who did not – due to the antioxidants in the fruit. Chronic high blood cholesterol is a major risk factor for heart disease.

Gorinstein of the university’s Department of Medicinal Chemistry and Natural Products, collaborated in the study with her long-time research partner Prof. Abraham Caspi, head of the Institute of Cardiology at Kaplan Hospital in Rehovot, as well as scientists from Poland and Singapore who participated in laboratory work connected with the project.

“For over 25 years, I’ve worked researching different foods and diets and their effects on cholesterol. I’ve done studies on beer, persimmons, hybrids like the pomelit, as well as traditional fruits like apples and pears – all with the goal of finding a diet that will decrease cholesterol,” Gorinstein told ISRAEL21c.

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

“I’m very proud of this study, because it included Israeli scientists, Israel grapefruit and Israeli patients,” said Gorinstein.

The 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. According to Gorinstein, 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 – also available in the US – were used in the study.

This study was very similar to the study that we conducted on the pomelit. But in this case, we used three groups ? two experimental and one control group,” Gorinstein said.

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, Gorinstein reported.

“In both experimental groups, the level of cholesterol was lowered. In addition, the triglyceride level ? which is a very important factor in arteriosclerosis ? decreased, considerably more in the group that ate the red grapefruit,” she said.

“It is likely that antioxidants in the grapefruits are responsible for their health benefits,” says Gorinstein, adding that the red variety generally has higher antioxidants than the white.

“But, perhaps in addition to antioxidants, there may be some other important compounds in red grapefruit which could be influencing the decrease of the triglyceride levels. Future research is very important.”

Both the fresh fruit and the juice are believed to be equally beneficial, 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.

“But, if you can lower cholesterol with natural products instead of medication, then it will be our victory,” said Gorinstein.

Refusing to rest on her laurels, the effervescent Gorinstein is already enthusiastically looking ahead to her team’s next challenge.

“The next project will be very interesting. We’re going to study the effects of exotic fruit on cholesterol.”

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