Provided by Australasian Science on 10/12/2004
by Luntz, Stephen

Originally Published:20041001.

Suspicions that a diet high in antioxidants can protect against Parkinson's disease and other forms of progressive brain decay have received a boost.

Previous research in the area suggested that high antioxidant diets protected animals against brain disease. A team at the Howard Florey Institute led by Prof Phillip Beart has now shown that antioxidants protect cultures of brain cells against attacks from toxic free radicals.

The brain cells in Beart's research were taken from rat brains, but they were selected from the areas affected by Parkinson's disease.

"Parkinson's disease involves oxidative stress because brain cells have chemical malfunctions and resultant toxic free radicals kill special dopamine-producing brain cells," Beart said. "When the brain makes dopamine it also produces toxic by-products, which are usually managed by the dopamine cells' inbuilt antioxidant systems in the healthy brain.

"Our study provides direct evidence that the flavonoid family of dietary antioxidants reduces the oxidative damage to cultured dopamine neurones dying by apoptosis (cell suicide), which is believed to be how human dopamine neurones die in Parkinson's disease."

Beart says there is a shortage of clinical studies investigating the effectiveness of antioxidants against brain diseases. "It's very difficult to pull patients off their treatment to test them with antioxidants. You have to maintain the drugs they are on and add antioxidants as an extra" However, this runs the risk of creating distortions in the results through potential interactions between treatments.

Even if clinical trials were conducted on brain disease patients, Beart is not sure how well they would work. "By the time you are getting most of the symptoms of Parkinson's disease probably 80% of the relevant brain cells are already dead. We need a genetic or blood test to detect the disease earlier."

Beart also doubts whether a diet of green tea, red wine and blueberries is really necessary for the general population. "The body is always producing toxic free radicals, but normally it mops them straight back up. It is only when it produces too many for some reason, when the body is under stress, that the antioxidants will work." However, overseas studies on animals suggest that when the need is there the equivalent of five cups of green tea per day would be enough to have a neuroprotective effect.