My Medical Bullshit Detector

I know little about medicine. I am unable to debate someone at an object level, ie “this drug affects that organelle which secrets the following hormone.” Yet I feel comfortable ignoring certain generic medical advice.

My Bullshit Detectors: #

1. Is there a good story for why cavemen were fine without this medical intervention? Is this intervention intended for everyone, or just me?
2. Is this intervention designed to cure me, or to resolve my symptoms?
3. How are my doctor’s incentives different from my own?
4. Is it possible to study this even in principle?

I: Is There a Good Story for Why Cavemen Were Fine Without This Medical Intervention? #

Does it strike you as odd that dentists recommend that almost everyone get their wisdom teeth removed? What happened to cavepeople? Did they all have horrible jaw pain in their twenties and thirties?^[1] Did they perform root canals with rocks?

If you ask an anthropologist, they’ll tell you: the human jaws we’ve found from before the agricultural revolution have perfect teeth. I’m sure some of the skeletons show teeth knocked out from blows. But the problems that modern orthodontia aims to fix — malocclusion, crowded and crooked teeth, overbites — are nonexistent in prehistoric skulls.

So why is my dentist telling me I have shit genes and need braces, wisdom teeth removal, and an Herbst appliance? It’s implausible that the human dental genome degraded so rapidly over the past 10,000 years.

We didn’t chew enough as kids. The muscles and bones of our jaws aren’t stimulated, so they don’t grow properly. This leads to crowded jaws, impacted wisdom teeth, and breathing issues.

I’m certainly not a dentist, so if your dentist wants to give your kid braces or take out their wisdom teeth, take their advice. It’s probably too late for your kid to start chewing more.

But if your kids are young enough: get them to gnaw on some bones or chew some gum.

Modern Americans have a weird physiological inferiority complex. The narrative goes: wild animals are by nature vigorous, strong, healthy, robust. They can sleep outside in the cold, fight off infections without drugs, skip meals to escape predators. Humans, thanks to millennia of civilized life, have become wimps, dependent on central heating and antibiotics, incapable of extended exercise without Clif bars and electrolyte goo.

Your genome is identical to that of the humans who, ten thousand years ago, slept outside in the cold, fought off infections on their own, and remained strong without food. Do we really need $200 Nikes for a jog?

There are a couple arguments you could make in favor of Nike, none of them very good:

1. We run on pavement, cavemen ran on dirt. Ignore for a moment that there are plenty of rocky surfaces in nature. If we just need a slightly softer surface, shouldn’t a thin rubber slipper be enough? Why do we need motion control, custom orthotics, a raised heel, rubber half an inch thick?
2. Cavemen didn’t run very often, and those that did got hurt frequently. This isn’t true.
3. I could be running around barefoot if I had grown up that way, but I’ve worn shoes all my life, so I’ll never be able to go without them. Let me tell you: I did it. It will take a couple weeks, but your feet can create the callouses it needs.
4. Streets are dirty! This has not caused any medical issues for me.

(In Chapter 25 of Born to Run Christopher McDougall argues far more eloquently than I ever could that your body was made to run barefoot. If you’re curious I strongly recommend you buy a copy; this is my favorite book ever.)

I try to let my body suffer at least a watered down version of all the things a wild human animal would. I swim in icy water, run for miles in the heat without much water, fast for a day or two every so often, fight off infections without the help of antibiotics or NSAIDs, expose my skin to a reasonable amount of sun for someone of my pale complexion. (I don’t expose myself to bugs. I hate bugs). You can find mountains of studies and commentary on the internet telling you that any of these things is helpful or harmful. A heuristic: if every prehistoric body experienced this, it’s good for mine to experience it too.

II: Is This Intervention Designed to Cure Me or to Resolve My Symptoms? #

Most doctors recommend icing and NSAIDs (eg Advil) after an injury. If your goal is to reduce pain and inflammation, then icing works. But after I sprain my ankle, reducing pain is not my goal. It’s a useful guide in how far I’ve progressed in my recovery. Nor is reducing inflammation. Inflammation is an immune response, bringing resources to the site of the injury so that your body recovers.

Dr. Gabe Mirkin coined the acronym RICE (Rest, Ice, Compression, Elevation) for treating soft tissue injuries. Yet even he now admits on his website that this approach, while succeeding in reducing pain and inflammation, slows recovery. He says himself:

Anything that reduces inflammation also delays healing

There is a pattern here:

1. The body has an ailment, and the immune system responds.
2. We associate our sickness with the immune response.
3. If an intervention reduces our immune response, we assume that we are getting better.
4. Healing is delayed.

Sometimes suppressing our immune response is exactly the correct intervention. If you have pneumonia and it’s giving you a 105 degree fever, the fever is going to kill you way before pneumonia will, so you should take NSAIDs and do whatever else you need to to reduce your fever. If you have a 101 degree fever, you have to decide whether short term pain reduction is worth it for a slower recovery (see study).

It always surprises me how common this mistake is. Here are some guesses for why:

1. Alleviating symptoms happens on a short timescale and is high-feedback.
2. Doctors are incentivized to do something, and often all they can do is alleviate symptoms.
3. Lessening immune response is sometimes the correct intervention.

III: How Are My Doctor’s Incentives Different From My Own? #

Doctors make money when they do things.

Doctors don’t want to get sued. They’ll intervene to ‘be safe’ or refuse to prescribe unpatented substances that don’t have FDA approval.

Doctors want to make you happy, which, by default, means doing something.

I often don’t accept an intervention a doctor recommends. The inverse is rare.

IV: Has This Really Been Studied? #

Food studies are famously bad (small n, observational, indirect). They’re expensive and hard to do well. People don’t like being told what to eat.

IRBs will block RCTs where the treatment group is something like ‘use a tanning bed to see if it causes skin cancer.’ Without reading any tanning bed study, I have a strong prior that it’s observational.^[2]

Know if a study is indirect (eg it shows lowered cholesterol but not lowered mortality).