Cranberries Curb Stroke Damage

But laboratory findings a long way from clinical practice, experts say

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HealthDay Reporter

MONDAY, Sept. 8, 2003 (HealthDayNews) -- There may be something about the traditional Thanksgiving meal that could minimize brain damage from a stroke.

Start looking at the bowl of cranberries.

Scientists have found preliminary evidence that these berries may reduce the cellular damage that is the devastating hallmark of a stroke.

The research, apparently the first to show a link between cranberries and stroke protection, is being presented Sept. 8 at the national meeting of the American Chemical Society in New York City.

Stroke is the third leading cause of death in the United States and the most common cause of disability in adults. There are different types of stroke but the most common, called ischemic stroke, occurs when a clot cuts off blood supply to the brain. Without the proper nourishment provided by the blood, brain cells start to die.

Cranberries, which contain high levels of antioxidants, have previously been shown to have health benefits with regards to urinary tract infections and possibly even cancer and heart disease.

"What they're looking at is neuroprotection, which is trying to minimize damage at the time the stroke is happening," says Dr. Keith Siller, director of the New York University Comprehensive Stroke Care Center. "People have advocated this kind of treatment. The problem is that nobody ever knows if there is merit because it hasn't been tested in a scientific manner. This study tries to do this."

The authors of this study, which was partially funded by the Cranberry Institute, cultivated rat brain cells and then exposed them to conditions similar to those experienced by a human brain during and after an ischemic stroke. One group of cells was deprived of oxygen and glucose, as happens during a stroke. The other group of cells was exposed to hydrogen peroxide, which is what happens after oxygen to the brain starts flowing again. During this latter phase, even more brain cell damage occurs.

The cells were further divided into different groups, each receiving different concentrations of cranberry juice. Exposure to the highest concentration of extract (about the same as half a cup of whole cranberries) caused a 50 percent reduction in brain cell death.

A separate study, conducted by one of the co-authors of this study, found blueberries had a similar effect.

The researchers aren't sure exactly why cranberries might have this salutary effect, but they do have theories.

"Cranberries have a lot of compounds that are really strong antioxidants which neutralize free radicals that cause damage to tissues and cells," says study author Catherine C. Neto, an assistant professor of chemistry and biochemistry at the University of Massachusetts-Dartmouth. "What we think is going on here is that the cranberry antioxidants are probably reducing the degree of oxidative stress that the cells are actually experiencing."

After blood flow reestablishes itself after a stroke, there appears to be a high concentration of free radicals that add to the damage caused by the stopped blood flow. "Antioxidants might be neutralizing free radicals that are generated and reducing oxidative damage," Neto says.

One of the problems with the study is that it took place in a controlled situation, which cannot be compared with what happens in humans.

"This is definitely not what happens in people," Siller says. "People come in after they're in trouble and we only have three hours to get things done. A neuroprotective drug could be successful, but by itself it's probably not good enough."

Even if there were such a drug, you would need a way to get it into the brain when the artery that normally delivers blood has closed down.

Also, the current results are a long way from producing anything to help stroke victims.

"The study has merit, but you can't make big conclusions from it," Siller cautions. "It's quite possible that something found in cranberries is indeed helpful but to go from the Petri dish to 'everyone should eat a pound of cranberries every day' is a giant leap of faith. Anything that promotes discoveries in this field is of benefit, but this is not a substitute for traditional medication like aspirin or blood thinners."

More information

The National Stroke Association has information on preventing and recovering from a stroke.

SOURCES: Catherine C. Neto, Ph.D., assistant professor, chemistry and biochemistry, University of Massachusetts-Dartmouth, North Dartmouth, Mass.; Keith Siller, M.D., assistant professor, neurology, New York University School of Medicine, and director, New York University Comprehensive Stroke Care Center, both New York City; Sept. 8, 2003, presentation, American Chemical Society national meeting, New York City

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