Does Coffee's Caffeine Protect Against Parkinson's Disease?

From the WebMD Archives

May 23, 2000 -- On the same day actor Michael J. Fox officially announced the launch of a foundation for Parkinson's disease research that bears his name, a new study was released showing that men who don't drink coffee are two to three times as likely to get the disease as are men who do drink coffee.

And the more caffeine from coffee the men in the study consumed, the lower their incidence of Parkinson's disease. For example, men who don't drink coffee at all were five times as likely to get the disease as were those who drink seven cups, or 28 oz., or more each day.

But don't raid your grocery store just yet. "It's too early to say we should go out and drink lots of coffee to avoid getting Parkinson's disease," researcher G. Webster Ross, MD, tells WebMD. "We can't yet establish a cause-and-effect relationship."

"To do that, you'd have to do a controlled study looking at the effect of coffee over a five- to 10-year period," Jay Gorell, MD, tells WebMD. Gorell, who reviewed the study for WebMD, is division head of movement disorders at the Henry Ford Hospital in Detroit.

Parkinson's disease now affects three of every 100 people over age 65, but as people continue to live longer, this percentage could double in the next 30 to 40 years. The disease also can afflict younger people, like the 38-year-old Fox, who has had Parkinson's since 1991.

In a news conference Tuesday on Capitol Hill, Fox announced the formation of the Michael J. Fox Foundation for Parkinson's Research and its merger with the Parkinson's Action Network, which together will lobby for research funding and try to increase awareness about the disease.

"I have gone from patient to advocate in a day," Fox said. "I will do everything I can to live up to the honor of representing the Parkinson's community to the best of my ability." Fox, who is leaving the ABC series "Spin City" to funnel his time into keeping "the momentum going" and finding a cure "in less than 10 years," only two years ago announced that he suffered from the disease.

"My approach to Parkinson's in the first few years was to keep it as close [to the vest] as possible," he said, but, going it alone became exhausting. "One craves the company of other people with the same struggles and challenges," he said.

"It's helped me tremendously, the feeling of being able to serve ... to be able to offer up my story, as much as it is uncomfortable sometimes," he said.

In Parkinson's disease, brain cells responsible for controlling movement die off, causing stiffness, uncontrolled shaking, and other symptoms. Even with treatment, most patients get worse with time, and may eventually need wheelchairs or become bedridden.

"We have a tremendous opportunity to close the gap between what we know and what we don't know about treating Parkinson's," Fox said in a press release Tuesday. "The scientific community and I believe that with a significant investment in Parkinson's research, new discoveries and improved treatment strategies are very close at hand."

According to research reported in the May 24/31 double issue of the Journal of the American Medical Association, the caffeine in coffee, rather than its vitamins such as niacin or other nutrients, seems to be important in lowering the risk of Parkinson's disease.

"We still see a very strong effect if we look at caffeine consumption from tea, chocolate, or cola," says study author Ross, who is a staff neurologist for Honolulu Department of Veterans Affairs. "Milk and sugar that people put in their coffee had no effect."

"The effect is stronger in those drinking more coffee, [suggesting] a real biologic effect," fellow researcher Caroline Tanner, MD, PhD tells WebMD. "Laboratory research may help to identify whether caffeine or some other component of coffee contributes to this, [which could] lead to the development of new treatments." Tanner is a neurologist and director of clinical research at the Parkinson's Institute in Sunnyvale, Ca.

This study followed more than 8,000 Japanese-American men in Honolulu for up to 30 years. Earlier studies had found that cigarette smoking was also associated with decreased risk of Parkinson's disease.

"Personality types may play some role in Parkinson's disease," says Ross. "Individuals who engage in thrill-seeking, high-risk behavior may have a lower risk of developing Parkinson's disease. Coffee intake and cigarette smoking both fit in with this type of thrill-seeking behavior, because these individuals may like the [high] they get from caffeine or from smoking."

Despite its possibly promising effect on Parkinson's disease, cigarette smoking is associated with health risks including cancer and heart disease, and even caffeine may cause health problems such as fibrocystic breast disease or irregular heart beats in some people.

Ross speculates that caffeine might protect against Parkinson's disease by counteracting free radicals thought to damage nerve cells, or by blocking specific nerve endings called adenosine receptors, which may relieve stiffness and related symptoms.

"Since the mid-1970s there has accumulated animal data suggesting ... that [blocking] adenosine receptors may cause symptomatic relief in Parkinson's disease," Bertil Fredholm, MD, PhD, tells WebMD when asked about the biological implications of this study. He is a professor of physiology and pharmacology at the Karolinska Institute in Stockholm.

But the link between coffee and Parkinson's disease may not reflect any beneficial effect of coffee at all. "People with early symptoms of Parkinson's disease may be [using the stimulant effect of coffee] to treat the symptoms of stiffness so that they go unrecognized," says Ross. "Or, people destined to get Parkinson's disease may have an intolerance to coffee because they get nausea, anxiety, or other symptoms when they drink it."

"Differences in caffeine metabolism might be one mechanism that could account for these results," Gorell says. "But without additional research, that's just speculative."

Genetic and environmental factors may work together to increase the risk of Parkinson's disease. Because this study was done in older, Japanese-American men, Gorell says that "we need to do more studies in women and in other racial groups."

"I hope that this study will lead to more trials of caffeine or other adenosine [blockers in Parkinson's disease]," says Ross. "There is research going on to try to create medications that will have specific effects on the adenosine receptors, and that will be more potent and selective, with fewer side effects."

To read more, visit our Diseases and Conditions Parkinson's page.

Vital Information:

  • Parkinson's disease now affects three of every 100 people over age 65 and occurs when the brain cells that are responsible for movements die off, causing stiffness and uncontrolled movement.
  • According to a new study, people who drink coffee have a decreased risk of developing Parkinson's disease.
  • It is unknown whether coffee actually protects a person from getting the disease, or whether some other factor found among coffee drinkers, such as a thrill-seeking personality, is responsible.