Hacker News Reader

Comment by dragonwriter | Hacker News Reader

> Where did Western people get iodine before it was necessary to add it to salt?

Some lived near the sea and had high seafood diets, but most were just iodine deficient, which doesn't stop a population from surviving, though it leads to suboptimal outcomes in a number of dimensions.

There is this wierd pervasive mythology that before modern times people lived in an ideal state (at least in terms of nutrition), so any present deficiency from the ideal must reflect a difference between modern and premodern society. Past conditions were at least minimally adequate for survival and reproduction, or we wouldn't be here, but there's no real basis for assuming that they were in any way ideal.

View on HN

You can make a good argument that before agriculture, people lived in a "steady state" hunter gatherer society for at least hundreds of thousands of years, to which they were extremely well adapted adapted evolutionarily.

Let's repeat that because it's important and counterintuitive: Those conditions were ideal for us because our species changed to fit the conditions.

What's happened since is a crazy rollercoaster ride of life conditions changin much faster than evolution has any chance of keeping up with, and premodern society in the sense of preindustrial can in no way be presumed to be ideal.

> for at least hundreds of thousands of years, to which they were extremely well adapted adapted evolutionarily.

Hundreds of thousands of years is not a really long time in evolutionary terms, and evolution doesn't necessarily, even given a long time, get out of a good-enough local optimum to “extremely well adapted”.

It's also debatable whether conditions in which humans evolved are really a steady state.

More to the point, humans being ideal for the conditions—what the argument from evolution suggests—is not the same as the conditions being ideal for humans.

I thought about responding to these critics, but they don't really say much beyond "you never know!"/"don't be too sure!", so I'll leave things as is.

Species don't change so that the conditions become ideal for that species, species change so that the species is (close to) ideal for dealing with that environment. This is a very important distinction. Certain plants may grow in the desert with very little water, but that doesn't mean that they don't grow faster with more water.

Ideal in the sense of "outcompeting the other animals of the time in terms of breeding". Far from ideal in the "I'd like to be happy" sense.

Didn't people in early Hunter-gatherer societies have drastically lower life-expectancy, height and IQ as compared to modern humans living in industrialized nations? Evolution may not value those traits all that much, but we certainly do.

True, but it's not like diet is the only thing different between their lives and ours.

I think violence, poverty and disease were the bigger factors.

All I'm claiming is that our digestive system is adapted to what we had to eat where our species evolved.

Umm, if you're gonna parrot vague evo-psych-anthropological arguments, they need to be more solid that this.

Cursory Google search seems to indicate that some fruits, as well as potatoes (!), dairy products, fish, and eggs contain iodine. Even if you were a very poor European peasant in the middle ages, you would still get to eat potatoes, milk, and smelly not-fresh fish, so the iodine problem probably would be bad but not terrible. If you were a rich person or someone who lived on the coast, I would speculate that you'd be pretty much fine.

> Even if you were a very poor European peasant in the middle ages, you would still get to eat potatoes

Potatoes are a New World crop. Medieval European peasants didn't have them.

> Even if you were a very poor European peasant in the middle ages, you would still get to eat potatoes

No, you wouldn't, as a European of any social class, except maybe in the very late middle ages at the boundary of the Renaissance; potatoes were a New World import in the 16th century, which might just still be considered the Middle Ages in some parts of Europe.

Preserved fish (dried, smoked, salted, or pickled) has been a common food for millennia. It's arguable if it's "smelly", it's by definition not fresh, but it's definitely fine to eat.

It was an important source of protein in centuries past, and was traded all over Europe. It would've also been an effective way for inland residents to get iodine.

As I understand it, the iodine in dairy typically comes from the products used to clean and sanitise the milking and storage equipment (iodophor). It's not inherent in the dairy itself, otherwise we could just eat the cow's grass to obtain iodine

> As I understand it, the iodine in dairy typically comes from the products used to clean and sanitise the milking and storage equipment (iodophor).

It's possible this has some contribution, but it's not the main source.

> It's not inherent in the dairy itself

Yes, it is; in cows (and humans) mother's milk is where young who aren't eating anything else get their iodine.

> otherwise we could just eat the cow's grass to obtain iodine

Well, except for the fact that grass doesn't work well in the human digestive system, and you'd have to eat a lot of it, sure.

The Catholic church has a rule not to eat meat on Friday and fish was popular instead. Not sure when that started but maybe forcing a bit of more expensive fish into the diet was quite useful for dietary health.

As I understand it, meat (non-fish meat) was considered a luxury, not the other way around. But I'm not 100% sure of the context.

Before refrigeration and the steam engine fish prices would rise dramatically and quality decrease quickly as you move away from the ocean. Salting was done to preserve some types of fish, but this processing would add cost. As discussed elsewhere, people inland are the ones who would lack iodine in their diets and in those locations and I would guess fish would be the more expensive than meat in those locations. It would be interesting though to see a list of market prices for meat and fish from some inland city back then.

According to my endocrinologist, about 15% of women in most western countries are Iodine deficient, and about 10% of men. The difference is mostly because women tend to dislike seafood.

In Australia the situation is a lot worse, she said, because our soils are so depleted. No just of Iodine but many other nutrients.

Wait, women dislike seafood more than men? That's the first time I'm hearing this. In landlocked Europe I'd be guessing the opposite. Is there some biological explanation?

Not knowing much about the biochemical effects of iodine: is it possible Western people need less iodine? Northern Europeans evolved to have lighter skin because they needed more Vitamin D from the limited sunlight. I wonder how much genetics play a part in what defines the "ideal state".

> Not knowing much about the biochemical effects of iodine: is it possible Western people need less iodine?

Since the identification of the widespread deficiency and it's effects which motivated iodization of salt was first in the West among Western people, probably not meaningfully. Unlike sunlight which is highly latitude dependent, iodine availability is much more location dependent, and the high availability places (places with access to fish, approximately—both saltwater and many freshwater locations) are also where pre-civilization human populations tended to be most concentrated.

Reply on news.ycombinator.com