Grapefruit May Improve Cholesterol

But Grapefruit Affects Some Drugs, so Check With Doctor First

Medically Reviewed by Louise Chang, MD on February 10, 2006
From the WebMD Archives

Feb. 10, 2006 -- Grapefruit -- especially red grapefruit -- may improve cholesterol, according to a new study.

Natural compounds called antioxidants may get the credit, but that's not certain, the researchers note.

However, grapefruit and grapefruit juice interact with several types of medicine, including some cholesterol-lowering drugs. Grapefruit's interaction with certain medications can cause levels of medicine to rise in the body and lead to serious side effects. Before you head to the grocery store, check with a doctor about grapefruit's effects on your medications.

The new study was done in Israel. It was recently posted online in the Journal of Agricultural and Food Chemistry.

The researchers included Shela Gorinstein, PhD. Gorinstein works in Jerusalem at The Hebrew University-Hadassah Medical School's department of medicinal chemistry and natural products.

Low-Fat Diet, Daily Grapefruit

The study included 57 people with high cholesterol. They had had coronary bypass surgery at least a year before the experiment.

The patients had already unsuccessfully tried a cholesterol-lowering statin drug (such as Zocor). They hadn't taken any drugs that cut cholesterol or boost antioxidants for at least 30 days before the study.

The researchers split the patients into three groups. For 30 days, all groups ate a low-calorie, low-fat diet. One group added a daily red grapefruit. Another group got a white grapefruit every day. For comparison, the third group didn't eat any grapefruit during the study.

The red grapefruit group improved their cholesterol most, followed by the white grapefruit group. They ended up with notably lower total cholesterol and LDL ("bad" cholesterol) than the comparison group.

Bonus With Red Grapefruit

The red grapefruit group also improved their triglycerides (blood fats). Triglycerides didn't change much for the other two groups, write Gorinstein and colleagues.

Red grapefruit has more antioxidants than white grapefruit, the researchers note. They call for more studies to see if those antioxidants deserve the credit for the study's findings, or if there's another explanation.

Meanwhile, Gorinstein's team writes that a daily red grapefruit might be a helpful addition to a heart-friendly, low-fat diet for people with high cholesterol. But remember to check with your doctor first if you take any medicine, even if it's not a cholesterol-lowering drug. Other types of medications that can interact with grapefruit juice include drugs for blood pressure, heart rhythm, depression, anxiety, HIV, immunosuppression, allergies, impotence, and seizures.

Show Sources

SOURCES: Gorinstein, S. Journal of Agricultural and Food Chemistry, Feb. 3, 2006; online edition. News release, American Chemical Society.
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