Eat spice to live, not live longer

I’ve been traveling a lot this summer. So I’ve had to have a “go-to” hot sauce that I can have on my person. A lot of restaurants have the standard trio of Sriracha, Tabasco, and Tapatio (and like free wi-fi, the higher end restaurants are the least stocked with the sauce). They’re serviceable, but they are to hot sauce what Wendy’s, McDonald’s, and Burger King, are to hamburgers. So often I try and make it to a market with a large Mexican food section and see if there’s anything that is palatable. The worst situations you encounter are when you go into a Food Co-op, because some of the buyers seem to think that carrot juice with a tincture of paprika will suffice as long as it is organic and locally sourced. Well, I settled on El Yucateco Green Habanero Hot Sauce for this trip. I’ve had it before, and it’s not the most distinctive in flavor, but I’d give it a straight B. It has a kick, it doesn’t have conflicting tastes, and the aftertaste doesn’t linger excessively.

So as you might know, I like my hot sauce. I’m the Ronda Rousey of hot sauce consumption. If you think you can handle it, bring it. I’ll be at ASHG 2015 in Baltimore in a few months. I threw down the gauntlet. I’m game if anyone who wants to challenge me in downing sauce or pepper, with the proviso that they can’t be double null on TRPV1. The “puny human” David Mittleman rashly took up my challenge. We’ll see if he’s all talk.

I bring up the sauce because the media is going crazy over a new paper. Here’s The New York Times, Eating Spicy Food Linked to a Longer Life:

Study participants were enrolled between 2004 and 2008 in a large Chinese health study, and researchers followed them for an average of more than seven years, recording 20,224 deaths. The study is in BMJ.

After controlling for family medical history, age, education, diabetes, smoking and many other variables, the researchers found that compared with eating hot food, mainly chili peppers, less than once a week, having it once or twice a week resulted in a 10 percent reduced overall risk for death. Consuming spicy food six to seven times a week reduced the risk by 14 percent.

This is a Chinese study. The sample sizes are large. I went to the original paper. It’s ungated, read it, Consumption of spicy foods and total and cause specific mortality: population based cohort study. I wanted to check out how robust this result was. Well, look at the figure at the top of this post. I wouldn’t say it’s a slam-dunk. The effect is weak in some subgroups, and goes away for those who drink. But the general trend is clear. There does seem to be a negative correlation between mortality and higher spice consumption across many subpopulations. They claim to have controlled for a lot of demographic variables, and I sort of trust them. But it’s really nice to see this sort of figure that lays it all out.

I’m not sure that they really smoked out all the correlations. After all, those who like the taste of spice could simply be superior human beings. How can you control for that confound? But in any case, I did stumble on this interesting related paper, Mice That Feel Less Pain Live Longer:

To investigate further, researchers from the University of California (UC), Berkeley, bred mice without a pain receptor called TRPV1. Found in the skin, nerves, and joints, it’s known to be activated by the spicy compound found in chili peppers, known as capsaicin. (When you feel like your mouth is burning after eating a jalapeño, that’s TRPV1 at work.) Surprisingly, the mice without TRPV1 lived on average 14% longer than their normal counterparts, the team reports today in Cell. (Meanwhile, calorie restriction—another popular way of lengthening mouse lifespans—can make them live up to 40% longer.) When the TRPV1-less mice got old, they still showed signs of fast, youthful metabolisms. Their bodies continued to quickly clear sugar from the blood—a trait called glucose tolerance that usually declines with age—and they burned more calories during exercise than regular elderly mice. 

…Already, diets rich in capsaicin have been linked to lower incidences of diabetes and metabolic problems in humans, he notes. So might spicy foods be a way of extending life? Maybe, Dillin says, but you’d have to eat a lot of them over a long period of time. “Prolonged exposure to capsaicin can actually kill the neuron” that transmits signals from TRPV1, he explains. Knocking out those signals might mimic the effects of being born without TRPV1 in the first place and, therefore, could lead to a longer life.

Yes, a friend of mine with a neuroscience background told me he suspected that I’ve knocked out all the neurons that handle signals from TRPV1. The 14% mortality reduction is interesting, because it’s in the same range as the human study above. But, you aren’t going to live 40% longer if you engage in calorie restriction. There’s only so much you can extrapolate from mice.

People have been worried and curious about my spice consumption for years. When people ask if there’s a reason I put this stuff in my mouth my response is straightforward: it tastes good.

When I was a kid shrimp was my favorite food. I’m Bengali at least to that extent. Today shrimp is still my favorite food (and I can report that the preference is heritable). But, shrimp is high in cholesterol. When I was growing up people were scared of cholesterol and fat. Doctors advised my mom to reduce our shrimp intake. It really made me sad, and I’m not a particularly food obsessed person. Give me shrimp, hot sauce, and some fruit, and I’m good.

Well, you know by now that the guidelines against dietary cholesterol intake have been pretty much dropped. Turns out that dietary intake is irrelevant for most people. And now there’s this: Dietary cholesterol and cardiovascular disease: a systematic review and meta-analysis:

Results: Forty studies (17 cohorts in 19 publications with 361,923 subjects and 19 trials in 21 publications with 632 subjects) published between 1979 and 2013 were eligible for review. Dietary cholesterol was not statistically significantly associated with any coronary artery disease (4 cohorts; no summary RR), ischemic stroke (4 cohorts; summary RR: 1.13; 95% CI: 0.99, 1.28), or hemorrhagic stroke (3 cohorts; summary RR: 1.09; 95% CI: 0.79, 1.50). Dietary cholesterol statistically significantly increased both serum total cholesterol (17 trials; net change: 11.2 mg/dL; 95% CI: 6.4, 15.9) and low-density lipoprotein (LDL) cholesterol (14 trials; net change: 6.7 mg/dL; 95% CI: 1.7, 11.7). Increases in LDL cholesterol were no longer statistically significant when intervention doses exceeded 900 mg/d. Dietary cholesterol also statistically significantly increased serum high-density lipoprotein cholesterol (13 trials; net change: 3.2 mg/dL; 95% CI: 0.9, 9.7) and the LDL to high-density lipoprotein ratio (5 trials; net change: 0.2; 95% CI: 0.0, 0.3). Dietary cholesterol did not statistically significantly change serum triglycerides or very-low-density lipoprotein concentrations.

Nutritional science in general doesn’t kill directly. Perhaps some people have type II diabetes because of the fat fear years when they gorged on Snackwells. But the biggest impact is that overreaction, and to a great extent craven behavior in the face of politicians looking for The Answer, results in reduced quality of life for tens millions. That matters. You sure as hell are going to get more skepticism from me about how something that I put in my mouth is good or bad from me now.

Do I hope that eating a lot of spice is healthy for me? Yes. Do I believe that this is a true result that will hold over time? Hell if I know. I’m just going to continue eating tasty food. End of story.