That's always the same story. A group of researchers finds a funny correlation in the data. They don't know the cause of the correlation, but they just write an article explaining that. Of course, the article if full of conditionals and sentences like: "this should be investigates further".
Then, a journalist finds this paper, eliminates all the conditionals and writes a click-bait article, so his employer can earn money from the announcers. Profit.
And I am not talking only about this article in particular, but about all the scientific journalism in general.
This is exactly how news is created these days, unfortunately. "Cancer cure using garlic!" is actually "Long term study of 1000 garlic eaters shows a 5% decrease in the incidence of gastrointestinal cancers."
You know… I'm not sure the press and the readers are more culpable that scientists and scientific institutions.
First, Universities have PR offices, a army or administrators and marketing people. They want attention and "clickbait"in their own way. It's not like they don't know that a nutrition study finding a correlation between chili and stomach fat will get traction in the world of "one weird trick." I don't think they are ticking all the boxes and misinterpreted despite all efforts.
Second, a lot of the science just isn't good. Not enough independently corroborating studies, hypothesis fitting… The world of health and nutrition has produced bad information that passed through to official recommendation used by governments, doctors… remember when we were supposed to be scared of eggs because of cholesterol? What was the evidence for that?
Third, science has rejected other knowledge systems like folk traditions, wives tails and such. That's great when they give us an alternative. The planets are not being pulled across the sky by chariots, no argument. But when it comes to nutrition, if you look back over the last 2 generations… listening to your grandmother would have been better than listening to science. They haven't earned credibility of "science."
You need a genetic variant that is pretty well studied and doesn't have too many effects, just a small handful that are well characterized.
A well characterized variant is in ALDH2. [1] People with normal ALDH2 metabolize alcohol normally. Those with variant ALDH2 process acetaldehyde poorly, so this unpleasant metabolite remains in their blood longer, causing discomfort and flush. Those with 0 variant alleles drink more than those with 1 allele; those with both mutations in alleles drink the least.
Let's say you had some variant like that, but for spicy food metabolism. The more variants in this spicy food metabolism gene, the more spicy the food felt to you so you might eat less.
If those who would be genetically expected to tolerate more spicy food survived longer than you would otherwise expect in a (genetic) dose-dependent fashion, then this would be suggestive that spicy food intake might be in the causal pathway of longevity. You would have to do additional work to be sure that the gene didn't do other things in metabolism (pleiotropy) that directly had effects on longevity.
