Drink coffee! It's (probably) good for you!

UT rarely offers health advice, but this study is too exciting to ignore

The best health and nutritional advice is the simplest.

Don’t eat too much. Get sunlight. Don’t do drugs. Exercise body and mind. Most of all, don’t believe any one food or medicine is the fountain of youth.

Still, every so often, The Science (TM) stumbles on a hopeful nugget (editorial note: can nuggets be hopeful?).

Like last week - when researchers from Harvard reported drinking several cups of coffee or tea a day notably reduced the risk of dementia over decades.

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(Cheaper than a cup of coffee! Save your brain for pennies a day.)

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The Journal of the American Medical Association published the finding, which comes from two long-running observational studies on over 130,000 nurses and other medical professionals.

The larger study, the “Nurses Health Study,” was begun in 1976. The second started in 1986. Both collect detailed health data on their subjects over time. The researchers then follow them for cancer, heart attacks, and other problems, including dementia.

In this case, data on caffeine consumption revealed a powerful signal.

In the group of almost 87,000 female nurses, the ones who drank the most coffee — over four eight-ounce cups per day, on average, or almost 300 milligrams of caffeine — had about 70 percent fewer cases of dementia than those who did not drink coffee.

The researchers then adjusted for other differences between the two groups, like their weight, how much they exercised, if they were married, and if they smoked.

Those changes reduced the difference substantially. But the coffee drinkers still had a 25 to 30 percent lower risk of getting dementia over several decades.

Caffeine was also protective for the 45,000 men in the second group, though the men did not drink quite as much coffee. The heaviest drinkers averaged about 2.5 cups a day, or about 150 milligrams.

When the two groups were combined, the results suggested that fairly heavy coffee consumption — three to four cups a day — could reduce risk of dementia by 20 or even 25 percent over decades.

Notably, tea also appeared to have a protective effect. Decaffeinated coffee did not. Those findings are additional circumstantial evidence that the protective effects are real and result from the biological changes caffeine produces.

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(Juan Valdez wasn’t real, but coffee’s benefits might be.)

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To be clear, both of the studies generating this data are what scientists call “observational” studies rather than randomized controlled trials.

As a result, researchers cannot know for sure that the outcomes they find result from differences in the variables they measure rather than unseen “confounders.”

For example, it is possible in this case that people with a lower risk of dementia at baseline just like coffee and the short-erm cognitive boost from caffeine more. Or, conversely, that people stop drinking coffee as they experience symptoms of dementia, because its stimulation bothers them.

That said, large observational trials are essentially the only way to get data that spans decades on tens or hundreds of thousands of people. Randomized trials are too expensive and too complicated to go on that long — and expecting people to drink a randomly prescribed level of coffee for decades is impossible.

Plus, the data from this study is both more comprehensive and more likely to be accurate than most observational studies, because its subjects are healthcare workers. Presumably, they are likely to be more diligent than most people about tracking what they eat and drink and how much they exercise.

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(Yes, I’ll even give you good news! When I have it.)

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So, no, this paper does not prove that drinking coffee is good for you. And drinking so much that it interferes with your sleep is a bad idea. Insomnia is very bad for long-term health, including by increasing dementia risk.

That said, the paper should make you feel a little better about your morning jones for Starbucks. And if you are on the fence about that second cup before lunch… well, why not?

The brain you save may be your own.