Eating berries may prevent Parkinson’s disease

Two or more cups of berries a week may protect against Parkinson’s, according to a study of more than 130,000 American men and women.

It’s the first prospective study in humans — meaning it looked at people initially without Parkinson’s disease and followed them over time — to explore the association between flavonoids and the risk of developing the debilitating brain disorder.

Flavonoids are natural compounds that have an antioxidant effect. Blueberries and strawberries are high in flavonoids, as are tea, apples, oranges, orange juice and red wine. Other studies have suggested flavonoids may account for lower rates of stroke and other vascular diseases among wine drinkers.

The new research included 49,627 men in the U.S. Health Professionals Follow-up Study and 80,171 women from the Nurses’ Health Study. The researchers calculated daily flavonoid intake and then followed participants up for 20 to 22 years to see how many developed Parkinson’s disease.

Overall, 805 people — 438 men and 367 women — were diagnosed with Parkinson’s during followup. After taking age, smoking and other known risk factors for Parkinson’s into account, the researchers found that people who regularly consumed foods rich in anthocyanin — a type of flavonoid mainly obtained from berries — had a lower risk of developing Parkinson’s.

People who ate two or more servings per week of berries (a serving was one cup) were about 25 per cent less likely to develop Parkinson’s disease than people who had less than one serving per month.

When the researchers combined all flavonoids together, “we found a significant protective effect in men, but not in women,” said study author Xiang Gao, of the Harvard School of Public Health in Boston.

Men who consumed the most flavonoids were about 40 per cent less likely to develop Parkinson’s disease than men who consumed the least amount.

More research is needed to explain the gender difference. But, overall, “Our findings suggest that flavonoids, specifically anthocyanin, may protect against the development of PD,” according to the authors.

The study is to be presented in April at the American Academy of Neurology’s meeting in Honolulu.

Exactly how flavonoids might protect against the degenerative brain disorder isn’t known. But Gao said several animal studies have been published showing “a very consistent neuroprotective effect” on the brain.

First, flavonoids are powerful anti-oxidants, which stop the damaging effects of free radicals on cells. As well, flavonoids help reduce inflammation and help regulate signalling between nerve cells in the brain, which helps keep brain cells alive.

Parkinson’s results from a loss of brain cells that produce dopamine, a chemical that carries signals between nerve cells that co-ordinate movement. When dopamine-producing cells die, the symptoms of Parkinson’s appear. There is no known cure, and the risk of Parkinson’s increases with age.

The findings need to be replicated by others. But, “berries are relatively safe,” said Gao, an instructor in medicine at Harvard Medical School and associate epidemiologist at Brigham and Women’s Hospital.

“I don’t think it would be a bad thing to include berries as part of your regular food.”

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