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Eating spicy foods is not a quick prescription for a longer life

Before you run out and re-stock your refrigerator with fresh chili peppers, you should know that this study’s findings come with some major caveats.

Could eating spicy food — particularly food seasoned with fresh chili pepper — help you live longer?

That’s certainly what some headlines suggested last week after the publication in the BMJ of a large study from China that looked at the link between spicy-food consumption and how long people live.

The study, which involved more than 500,000 Chinese residents aged 30 to 79, reported that individuals who ate spicy food six or seven days a week were 14 percent less likely to die during a seven-year period than their peers who ate spicy food less than once a week.

The effect seemed to be stronger among people who consumed fresh, rather than dried, chili pepper (the main spice used by the Chinese participants in this study).

The effect was significantly weaker, however, among people who also drank alcohol.  (That’s not good news for individuals who can’t imagine eating chicken vindaloo, red curry or pork tacos without their favorite brew.)

Correlation, not causation

But before you run out and re-stock your refrigerator with fresh chili peppers, you should know that this study’s findings come with some major caveats. 

To begin with, this was an observational study, which means, of course, that it cannot prove cause and effect — a factor the study’s authors themselves take pains to point out.

The researchers did control the study’s results for factors that are known to influence longevity, such as exercise, diet, income and smoking. They also excluded people who had diagnosed heart disease or cancer at the start of the study.

But people who enjoy spicy foods might be healthier than their non-spice-loving peers in other ways. For example, the participants who ate the greatest amount of chili peppers tended to live in rural areas of China. Perhaps they cook their foods (spicy or not) in more healthful ways than those living in urban areas. Or maybe there’s some other characteristic about their rural lifestyle that makes them healthier.

In addition, because the study was conducted entirely in China, its results are not necessarily transferable to populations elsewhere in the world, including here in the United States. 

Doing the math

This isn’t the first study to suggest that capsaicin and the other bioactive ingredients in chili peppers may be beneficial to our health.

One intriguing area of investigation involves the effects that spices, particularly those with capsaicin, may have on gut microbiota, which are the microorganisma metagenome-wide association study of gut microbiotas — sometimes beneficial, sometimes not — living in our digestive tracts. Some research suggests that the composition of our gut bacteria may influence our risk of diabetes, heart disease and certain types of cancer.

But that research is still in its early stages.

Furthermore, even if the current study’s findings were solid proof of the life-extending advantages of eating chili peppers, the number of people who would benefit would be very low. Dr. F. Perry Wilson, an assistant professor of medicine at Yale University, points this out in his short (and entertaining) video analysis of the study for MedPage Today. 

“If you’re doing the math,” he says, “you’d have to take around 2,800 people who eat mild foods and covert them into spice-a-holics to save a single life.”

No quick fix

Wilson also explains why studies like this one grab headlines — and resonate with the public. It’s because we’re looking for a quick, easy way of getting control of our health.

“This search for functional food, [for] specific ingredients that give specific health benefits  — your kale, your quinoa, your chili powder — is tempting because it offers a measure of control,” he says. “You don’t need a prescription. You don’t need a doctorate. All you need is some special knowledge, perhaps handed down through the ages, to protect you from any manner of ills.”

“It’s a nice thought,” he adds, but, alas, one that’s not backed up by the evidence.

You can read the BMJ study in full on that journal’s website. You can watch Wilson’s quick video analysis on the MedPage Today website.

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