Tea, dementia and the evolution of fake news


In her May 4 column titled “Tea can help prevent dementia,” Dr. Sadja Greenwood wrote about a research study from the National University of Singapore, concluding: “tea drinking reduces the risk of cognitive impairment in older people by 50 percent and as much as 86 percent for those genetically at risk of Alzheimer’s.” I was puzzled by that 50 percent claim, since it ran counter to what I knew as a neuroscientist. If the 50 percent conclusion purportedly reached in the study were true, then major tea-drinking countries should have much lower rates of dementia, but they don’t. For example, the United Kingdom and Ireland don’t have dramatically less dementia than coffee-drinking countries like France and Italy.   

It winds up that the actual research article said no such thing (the numbers 50 percent and 86 percent are not found in the article). Rather, the authors of the study state that tea consumption is associated with a modest reduction of cognitive impairment in women, and not in men, and in those carrying a certain mutation. Where did the 50 percent number come from?  

The Point Reyes Light is far from the only publication that misrepresented the Singapore study. You can find nearly the identical wording about the 50 percent and 86 percent prevention of cognitive decline in dozens of other internet news sources. A similar article in the Huffington Post was titled “Daily Cup of Tea Could Halve Your Dementia Risk, Study Suggests.” The author wrote: “That’s according to new research, which found drinking black (such as English Breakfast and Earl Grey), green or oolong tea reduced the risk of cognitive impairment in older people by 50%. In those who were genetically at risk of Alzheimer’s disease, the risk was reduced even further (by 86%).”  

How did this fake fact become the lead to dozens of stories? The scientists in Singapore published their study showing modest results that are not particularly novel or newsworthy, but I was unable to find any news source that wrote about the real findings. The culprit? A university press release that can only be described as over-hyped. It begins: “Tea drinking reduces the risk of cognitive impairment in older persons by 50 percent and as much as 86 percent for those who are genetically at risk of Alzheimer’s.” The senior author of the research paper was clearly in cahoots with this misrepresentation of his own paper because he gave a series of quotes for the press release that were equally over the top. Had the scientists put this 50 percent claim into their paper, I have little doubt it would have been rejected by peer-review, as their data don’t support that claim.     

This is a great example of the evolution of fake news. We all want to believe that scientific data validate some aspect of our lifestyle or belief system. The problem is that press releases are not reliable news sources. Folks putting them out often over-state their findings or twist the truth. In this example, we see dozens of journalists simply quoting the press release and never looking at the original scientific paper. That fake fact bounced around the internet and ultimately found itself into the Light.

Can you imagine if you believed everything put out by the White House in Sean Spicer’s press releases? Yet many of us place our trust in news sources that simply regurgitate what they are fed by press releases. When it gets written up dozens of times and goes viral, it becomes quoted as fact—when it is really a fake fact. 

What is the truth in this case? Just as tea-drinking cultures have published studies showing a correlation of tea with a reduction of dementia, so too have coffee-drinking cultures touted studies showing a correlation between coffee and a reduction of dementia. Several independent meta-analyses of the entire scientific literature on the topic (conducted by scientists with no skin in the game) have concluded a weak correlation between tea, coffee and caffeine and a modest prevention of cognitive decline. The correlation tends to show up in women, rather than in men, for reasons no one can explain.  

The consumption of both tea and coffee—and it looks like any source of caffeine – correlates with a modest prevention of cognitive decline. No, not 50 percent, and yes, you’d be better off exercising and leading an active lifestyle. I for one am going to continue to drink tea. Not because I regard it as medicine, but just because I like it and hope it is good for me. And I’ll continue to hope that one of my scientific colleagues will find a cure for Alzheimer’s before my own decline gets much worse. 

By the way, if you’re looking for the elixir of life, the Huffington Post appears to publish health stories based on every hyped press release that hits their inbox. In the last few years, you can find articles proclaiming that green or black tea, coffee, celery, chamomile tea, oregano and berries, among other panaceas, will all help prevent cognitive decline. One needs a healthy dose of skepticism when reading such stories.    


Corey Goodman, a Marshall resident, is a former head of neuroscience at the University of California, Berkeley, and an elected member of the National Academy of Sciences.