I do hope one of you thinks of a better title or a more coherent structure for the overall post.

This question was inspired by a comment chain about PFAS in Gore-Tex jackets under a different post here, but it's been a bit of a simmering question for me.

When reading through that thread, my immediate reaction was something along the lines of the following.

Unless you're directing traffic in Seattle or Scotland, wouldn't the amount of time you'd wear the jacket be too little to have meaningful exposure? It's not like you're walking into an oven where the polymers would break down from heat. Further, if it's GoreTex-appropriate weather, you'll near-certainly have additional clothing between your skin and the GoreTex.

I was bored at work today, so I had plenty of time for rumination and introspection. What I found so far is that my instinctive skepticism toward health-conscious rhetoric has these primary sources:

1. I listened to Stronger by Science's six-hour deep dive on aspartame. Their eventual conclusion is that aspartame does cause bladder cancer in rats & mice, but the equivalent doses for humans make fears over its use into a major nothingburger. A human would need to spend a year chugging down five gallons of Diet Coke each day for the elevated cancer risk to be statistically meaningful.
2. When I catch someone trying to be convincing in an area where I lack domain expertise, I judge them by their overall demeanor and (if I can catch on) general rhetorical logic [in that order] long before I consider the truth of their specific claims. The IRL people I've met who are most stridently into wholesome natural living have fervency and lack of appreciation that it's the dose that makes the poison to the degree that it makes RFK discussing vaccine policy sound grounded in reality by comparison. Perhaps if they were born in a different society, they'd make excellent temple priests who ensure no lazy shortcuts or "it's all we have available" excuses are made when it's time to ensure a full harvest. Instead, they're the kinds who play 50 million questions and have genuine concerns that the radio waves that connect my wireless headphones are giving me brain damage or control. [To be fair, there is some large selection effects here. My hobbies have a habit of attracting those who are so open-minded that their brains fell out. Since online interactions strip the majority of demeanor and previous interactions, I judge online strangers with strange opinions way less harshly than IRL contacts unless they've gone out of their way to be obnoxious. IRL, I'm exposed to a lot more generic chemicals bad rhetoric than in my usual online bubbles. ]
3. Based on 1, unless I have preexisting trust with a particular journalist, layman's science journalism—when it's performed by journalists dabbling in science rather than scientists trying their hands at public communication—is far too likely to overblow a headline or misrepresent the research conclusions. "Here are 30 links to news articles" doesn't appeal to me because 25 of them are probably copying each other (that's just how internet journalism works). It's highly unlikely that all 5 of the remaining links misread the original paper, but I'm not reading through all those (perhaps AI summarization could help here—at the very least it could identify commonalities and outliers for manual examination later).
4. Related to 2, two additional SMBC comics that share my attitude: Vitamin Water v. Butter and Pronounceable Ingredients Only

That said, sometimes the health nuts are correct. As it turns out, all the coughing smokers do is a strong sign that smoking is bad for your lungs.

What are some heuristics to sort health tips that get passed around without citation into one of the following buckets?

1. You'll notice the improvement within a week once you've finished withdrawal. Smoking, boozing, eating meat or alliums at dinnertime, and heroin are in this bucket.
2. The effect is real and significant, but you may not notice the impact until at least a year has gone by, if ever. Seatbelts and bike/horse helmets are the two examples that immediately pop to mind.
3. Technically non-zero, but ultimately trivial. The opening aspartame example would fit. In a similar line to doctors who recommend against treating prostate cancer because the treatments would shorten your lifespan by more than letting that cancer run its course and waiting for a heart attack or totally unrelated cancer to do you in, these interventions are meaningless to anyone who uses motor vehicles regularly.
4. Playground rumors or outright disinformation. Vaccines causing autism and yellow 5 as an HRT supplement b/c it shrinks your testicles belong in this wastebin.

Circling back to the impact of PFAS in Gore-Tex that inspired today's thinking, my layman's estimate that the effects on the factory workers who make a career out of working with the stuff is a low 2 when following proper safety procedures. Without them, a definite 1. For wearers of the stuff, a solid 3.

One final reason I may have been so fired up on this topic is that I listened to a highlight reel from a Congressional hearing round table on food & pharmaceutical safety last week. During the testimony, I had a nagging feeling that at least half of what they said was true, but the truth percent is below 75, and I had no idea which was which because all claims were presented with the same urgency.