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Comment by subsubzero | Hacker News Reader

This article got me thinking, if artificial light forever changed the way people sleep, what other modern changes have also altered life or physical characteristics of people long ago. 200 years ago everyone had perfectly straight teeth, some think heavily blended/processed foods may have lead to under developed jaws and crooked teeth for alot of modern people or possibly high sugar, its not known but something in the modern era changed our teeth structure for the worse.

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Food preservation and international commerce have eliminated seasonal diets. All of our fruits and vegetables used to be largely seasonal with only a handful that could be kept edible in cellars before canning. Meats, dairy and eggs too had seasonal ebbs and flows -- you'd slaughter your hogs in the fall as their forage ran out, your cows might dry up, your chickens probably stopped laying. Winter diets would grow steadily more monotonous and you might spend a few weeks going hungry.

The range of our diet had also globalized. Potatoes are now a staple worldwide, and tomatoes flavor dishes around the world from where they were developed. Spices aren't very exotic, even if some of us like our food plain.

And salt! Salt had gone from a spice and vital preservative with a value comparable to hard currency to something we throw on roads in the winter.

> 200 years ago everyone had perfectly straight teeth

Wait what? Citation needed please, I googled this and couldn't find anything. Our teeth were definitely bad 100 years ago, since we have images and video from that far back. The bad teeth are something that really struck me in "They Shall Not Grow Old": https://youtu.be/IrabKK9Bhds?t=57

Edit: Okay I see a Scientific American article about this here: https://www.scientificamerican.com/article/why-we-have-so-ma... so that means in 100 years we went from perfect teeth to terrible? Dang

> 200 years ago everyone had perfectly straight teeth

What makes you think that? That's not what evidence has ever suggested. https://www.usatoday.com/story/news/nation/2014/01/06/tooth-...

Regarding teeth, one thought is that over/underbite was less frequent before cutlery became commonplace. Our ancestors had to bite/tear their food using their incisors and canines a lot more than we do, which meant their jaws would strengthen in the biting position - thus with their lower and upper incisors aligned.

Personally I wonder if this would affect speech as well, so perhaps out ancestors sounded different too?

there is a theory that "modern" overbite lent itself to pronouncing f and v sounds, which are more tricky with perfectly lined up teeth

https://www.smithsonianmag.com/science-nature/ability-pronou...

Didn’t people lose teeth more often back then as well? Which would naturally lead to more gaps in the mouth and thus less crowding to push teeth inward.

On the point of teeth (and bones), going hungry increase growth hormone, which was good for the skeleton and thus straight teeth. You see this today with dogs prone to hip dysplasia, as a puppy they were likely overfed with not enough tryptophan (60mg converts to 1mg nicotinic acid in humans) or nicotinic acid (vitamin b3) in their diet, ergo not enough growth hormone and so you get Labradors and other dogs getting hip dysplasia.

Dont we see two sleeps in the older generations, known colloquially as the afternoon nap?

Japense kids with depression, were found to be driven to school where as those that walked to school for just 10-15mins iirc didnt get depressed according to one study. Blue light stimulates or helps increase the serotonin in the brain which creates wakefulness.

Its like blue light from computer monitors can keep people awake for longer at night which is why M$ introduce the blue light monitor which is a rip off of the original AFAIK of https://justgetflux.com/

>Dont we see two sleeps in the older generations, known colloquially as the afternoon nap?

Interrupted sleep in the middle of the night for a bit is something I always thought was a normal occurrence as you got older, based on my family.

The problem and solution has been known for almost a century now; check out the book 'Nutrition and Physical Degeneration' by Weston Price. 'The Dental Diet' is also solid reading.

I'm still working through the book, but the tl;dr is that it mostly just comes down to nutritional deficiency. People in the past ate pretty much strictly nutrient-dense foods, people today eat a lot of junk food, empty carbs, and generally foods that just aren't nutrient dense compared to what our ancestors ate (mostly vegetables and meats).

Can’t you make up for nutrition dense foods with supplements?

We're still discovering new plant molecules and the effects they have on us all the time. Supplements are never going to be able to completely make up for a diet lacking in real whole plant food & animal meat.

With respect to the question about underdeveloped jaws, that development takes place primarily during your childhood, so if you didn't have optimal nutrition at that stage you won't be able to fix that retroactively.

Plants picked in darkness have higher levels of melatonin (sleep hormone) in them than plants picked in daylight according to one study.

Do you have a citation for that? Google scholar isn't turning anything up for me, and I'm interested.

Maybe this? "Melatonin synthesis in rice seedlings in vivo is enhanced at high temperatures and under dark conditions due to increased serotonin N-acetyltransferase and N-acetylserotonin methyltransferase activities"

https://doi.org/10.1111/jpi.12111

"The opposite effect occurred during the night, in which the positive effect of darkness on melatonin synthesis was counteracted by the negative effect of a low temperature."

Seems suspect.

People for the last 10k years in agrarian societies mostly ate cereal grains, with a few exceptions like Mesoamerica where they ate beans, squash, and a cereal grain. Hunter gatherers eat a stunning variety of diets and archeology suggests this has always been true. In polar regions people subsist primarily on meat and animal fat, in other places primarily shellfish and small fish.

Air conditioning, refrigerators

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