Pat and Jim Roberts pack up a bag of grapefruit in Rockledge. Fla. Check with your doctor or pharmacist to see if your medication interacts with grapefruit or grapefruit juice. (Malcolm Denemark/Associated Press)Love 'em, hate 'em or just plain indifferent to them, one thing is certain: grapefruit can provide real health benefits. Like all citrus fruit, grapefruits are packed with vitamin C. They're low in sodium, high in pectin fibre and potassium and contain the antioxidant lycopene.

Despite its slightly bitter taste, a 250-mL chilled glass of grapefruit juice does wonders for your thirst, while adding less than 100 calories and 156 per cent of your daily vitamin C needs to your diet.

And there are other benefits.

A study published in the American Chemical Society's Journal of Agricultural and Food Chemistry in 2006 found that red grapefruit may help lower levels of bad cholesterol and fight heart disease.

Although it was a small study, the researchers from Hebrew University of Jerusalem said it appears that the high levels of antioxidants are responsible for the health benefits of grapefruit. The benefits extended to fruit and juice but seemed to be higher in red grapefruit.

The study was a needed pick-me-up for an industry that has been battered by bad news since 1989, when a researcher found that grapefruit juice interacts with a number of medications — and often not in a good way.

The researcher found that as little as 250 millilitres of grapefruit juice can affect you. And it doesn't help to increase the time between you have grapefruit or grapefruit juice and the time you have your medication. The effect of the grapefruit can last for up to 24 hours.

Chemicals in grapefruit juice and grapefruit pulp interfere with the enzymes that break down various drugs in the digestive system. That can lead to much higher levels than intended of drugs in the blood and an increased risk of potentially serious side effects.

The problem does not exist with other citrus fruit like oranges and lemons — but may with pomelos and Seville oranges.

In 2002, Health Canada issued an advisory warning people of the effects of grapefruit and fresh or frozen grapefruit juice on certain medications. Medicinal drugs — and some natural remedies — affected are used to treat conditions including:

• Angina.
• Anxiety.
• Cancer.
• Convulsions.
• Depression.
• Erectile dysfunction.
• Gastrointestinal reflux.
• High blood pressure.
• High lipid (cholesterol) levels.
• HIV/AIDS.
• Infections.
• Irregular heart rhythms.
• Organ graft rejections.
• Psychotic problems.

Grapefruit can cause problems with some of the most-widely used drugs, including Lipitor (used to treat high cholesterol) and Zoloft (used to treat depression and anxiety).

Minimizing your risk

Health Canada says if you're taking medication for any of the conditions listed above, stay away from grapefruit - until you've consulted with your doctor or pharmacist about your potential for an adverse reaction. Read the label on any food or natural health product you plan to consume to make sure they don't contain grapefruit, its juice or Seville oranges.

This citrus salad could cause you problems if you're on certain medications - unless you take out the grapefruit. (Canadian Press)A day after a study was released in January 2005 linking grapefruit juice to a man's death in Florida, the Florida Department of Citrus went on the offensive.

The agency demanded "clarification on allegations about grapefruit-drug interactions made without appropriate scientific support." Two years earlier, the department — along with the University of Florida, Tufts University and the U.S. Department of Agriculture — helped set up the Center for Food-Drug Interaction Research and Education. Two years later, the Center launched a website that contains a database of drugs that indicates whether — and to what extent — they may interact with grapefruit and grapefruit juice.

Meanwhile, the stories about grapefruit — positive and negative — keep coming. In February 2008, researchers found that a compound in grapefruit may prevent and stave off a chronic hepatitis C infection.

The researchers — at the Massachusetts General Hospital Center for Engineering in Medicine — said the flavonoid naringenin may prevent cells infected with the virus from secreting into healthy cells.

In April 2009, a case published in the Lancet medical journal reported that a combination of factors - including a grapefruit diet, birth control pills and a genetic mutation — nearly cost a U.S. woman her leg.

The study's lead author — Dr. Lucinda Grande, a medical resident at Providence St. Peter Hospital in Olympia, Wash. — said the woman's case was unique and should not discourage people from eating grapefruit.

"Grapefruit is not a danger to society," she said. "It just happened to be dangerous for this specific person in this specific situation."