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> Greenlanders haven't existed for millennia. Greenlanders have existed for just under a millennium.

I got google-y for fun and every scientific paper title implies its inuit greenlanders whom have the mutation, not the euro greenlanders, and greenland is about 90% inuit. The picture of the prof looks like he's a euro greenlander looks like Denmark heritage to me but who knows (and it doesn't matter much anyway).

wikipedia says the inuit greenlanders have been chillin on the island for near 5000 years now.

I would imagine due to intermarriage, if the euro greenlanders are outnumbered 10 to 1, that quite a few euro greenlanders have the mutation, but the paper titles all seem to imply inuit greenlanders only.

The wikipedia article implies the archeological inuit greenlander diet was mostly carnivore. That's actually pretty healthy as long as they eat enough organ meats but not too much (particularly liver)

Greenland may have been inhabited for 5000 years, but that does not mean they share a genetic heritage back that long.

The Thule people, from whom modern indigenous Greenlanders descend, originated around 1000 CE in Alaska.

I'm pretty sure the Inuit diets in Alaska and Greenland are pretty similar though, at least in terms of macronutrients (i.e. a lot of fat).

The diets are the same and the Alaskan Inuit also carry the SI deficiency alleles.

https://pubmed.ncbi.nlm.nih.gov/25452324/

I don't know where you're looking on Wikipedia, but Inuit Greenlanders arrived in 1200 AD

Source: https://en.wikipedia.org/wiki/Greenlandic_Inuit

It's also common knowledge, Inuit/Thule were pretty much the last ones that migrated from Asia across Bering. They displaced previous indigenous people that had been there for few thousand years before (at least in Canada).

They arrived in Greenland during the last millennium. Paleo-Inuit peoples have been in the Americas for probably around 5000 years. The previous indigenous people you're talking about were earlier branches of the same "family". Moreover, this particular mutation is known to be common in Arctic peoples as a whole, not just Greenlandic Inuit.

Yeah it even starts with something not backed up by the study it's reporting on:

"Imagine being able to swap out broccoli for sweets, Ben & Jerry's or some other sugary treat and achieve the same health benefits. This is fact not fantasy for about two to three percent of the Greenlandic population"

The study does not say sweets confer the same health benefits as broccoli!

It kinda does, partially and indirectly. The study indicates it's not a matter of them eating less sucrose, the benefits actually don't show up in the absence of sucrose in the diet. It essentially acts like soluble fibre.

Of course the micro-nutrients that would be in the broccoli don't materialize out of nowhere.

I only read the article (not the study) but I also take issue with the following:

> Imagine being able to swap out broccoli for sweets, Ben & Jerry's or some other sugary treat and achieve the same health benefits.

The study finds the genetic variation/gut bacteria metabolizes the sugar directly from the intestines as opposed to being deposited in the blood-stream and triggering insulin to remove it and begin either the metabolic process or storage.

That is a metabolic benefit for sure and as a result could protect from metabolic and chronic diseases. But nothing about that process improves the nutritional value/health benefits of the sugar. Broccoli contains vitamins, minerals, and potentially enzymes (depending on cooking method) which the sugar doesn’t gain.

The Thule people of which the Greenlanders seem to have been somewhat separate for at least 4000 years, this likely focuses on the Greenlanders because it is made by a Danish University. I don't think you can say that the same is not the case for other arctic populations, they just have no research showing that yet.

> If this mutation gives a health or fitness advantage it would be selected for.

This is not always the case. Be wary of assigning intent to a stochastic process like evolution. It's about probability, not certainty.

See: vagus nerve

> If this mutation gives a health or fitness advantage it would be selected for.

That’s not always how evolution works, especially when you’re talking about characteristics that (as the writer pointed out) were not present or used during evolutionary selection. Adaptations that are selected for can and frequently do have byproduct effects that are not selected for. There are words for these effects, like “vestigial”, “tag-along”, “spandrel”, “byproduct”, “non-adaptive trait”, etc., etc.

As the article points out, super high carb diets make them very sick, but what about the effects of lower or normal (pre 1900) carb diets when they're not feeling sick?

Given that its pretty well known that high levels of sugar in the gut cause gut bacteria to go wild, a very reasonable research hypothesis would be to figure out why their gut microbiome is naturally deficient, such that turbocharging it up with a dose of raw sugar beings their gut microbiome activity up to normal healthy levels.

Sure dumping 2 liters of pepsi soda in their gut might cause all kinds of IBS like symptoms when their guts explode. But in the old days they just ate a couple berries once in a while, or at least the article claimed that.

This could be something as trivial as lots of fat intake means lots of bile production means some probiotic bacteria that's sensitive to bile suffers, until they eat a tiny amount of sugar that lets them grow to normal levels.

Could look at what gut bacteria do in stereotypical average humans. Gut bacteria under normal conditions do churn out some thiamine, folate, biotin, riboflavin, vit K, and probably stuff I'm not able to find from a quick search at pubmed central.

I think a really good research paper would combine the article results with a hypothesis that greenlanders as a group suffer (or, archeologically suffered, or occasionally suffered, or their kids suffered, etc) from deficiencies in folate, biotin, vit K, etc, basically the list above, and turbo charging their gut bacteria with a dose of raw sugar makes the bacteria more active which brings their vit K level or whatever up to normal human levels such that they're healthier on average and/or their kids die less often etc.

I didn't google up much immediately for deficiencies in Greenlanders. Maybe folate. Small amounts of sugar in small intestine would superficially seem to help with that. Folate deficiency really screws up pregnant women. As a hypothesis for a future research paper, it all kinda adds up, almost too neatly (conspiracy theory like). So their diet is not exactly folate rich, their pregnant women get all messed up, someone gets a mutation where their gut bacteria which produce folate get turbocharged by a couple berries, thus producing more folate in their gut, which optimistically is absorbed by their pregnant women, so women with that mutation have like three times as many living children as folate-deficient women without the mutatuon, it all kinda adds up.

>Greenlanders haven't existed for millennia. Greenlanders have existed for just under a millennium.

That sentence is saying the diet is millennia old. The diet and genetic variation are also common to other Inuit populations.

And then that part about the gut biome “learning how to make energy out of sugar”, facepalm. How can you write this, it’s really bad indeed. Oh and swap broccoli for sweets oh Greenlanders, like not being able to take up sugar efficiently equates to not needing anything of nutritional value.

It doesn’t have to do with Greenland specifically but the Inuit lifestyle in general which is thousands of years old. Inuit settlement in Greenland may be more recent but people have practiced the Inuit lifestyle (and its almost 100% animal content) for much longer.

> If this mutation gives a health or fitness advantage it would be selected for.

the more important question is if a mutation presents as a disadvantage for reproduction.

In this case, for the Inuit, the common allele (for Caucasians) presents as a disadvantage.

They needed this polymorphism to survive on a diet with low sucrose.

I agree with the first part of what you said.

(Note: I am an amateur Nutritional Geneticist)

They said:

"The results demonstrate that carriers of the genetic variation have what is known as sucrase-isomaltase deficiency, meaning that they have a peculiar way of metabolizing sugar in the intestine. Simply put, they do not absorb ordinary sugar in the bloodstream the way people without the genetic variation do. Instead, sugar heads directly into their intestine."

Ha! What? SI, the gene that they studied, ONLY exists in the intestine. The inability to break down sucrose leads to microbe imbalance that concerts the sucrose to acetate. They are using the word "sugar" to cover everything from sucrose to any other oligosaccaride. They just do not understand the science enough. If you read the study it is clear.

And in NO way doe sthis mean that eating sugar is healthy for them as the title implies!!!! Look at what happens when you have this deficiency!

https://medlineplus.gov/genetics/condition/congenital-sucras... "After ingestion of sucrose or maltose, an affected child will typically experience stomach cramps, bloating, excess gas production, and diarrhea. These digestive problems can lead to failure to gain weight and grow at the expected rate (failure to thrive) and malnutrition. "

So this is NOT a great mutation. There is no such thing as a universal "great" mutation. These genetic changes are just one change in a probably network of changes in the Inuit. Others would include genes like FADS1 and FADS2 and CPT1A.

(NOTE: I have Saami heritage, who are the Inuit of Finland.)

"'It is probably due to Greenlanders not having had very much sugar in their diet. For the most part, they have eaten meat and fat from fish, whales, seals and reindeer. A single crowberry may have crept in here and there, but their diet has had minimal sugar content,' "

Here the researchers are correct, this is not only a Greenlander trait, but a common trait in all Inuit, and very low sucrose is common in all Inuit diets. https://pubmed.ncbi.nlm.nih.gov/25452324/

And this absolutely is a fitness example. For people with the common allele, the lack of sucrose in the diet leads to lower levels of acetate and these people would die off leaving the survivors with the less common allele to flourish.

>And in NO way doe sthis mean that eating sugar is healthy for them as the title implies!!!!

That's actually exactly what the study concludes. They say children do experience those symptoms, but adapt as adults and are better off for it.

The study does not conclude that at all. They only concluded they might be able to trick some people to make money off a a drug they will make.

Limitations: We hypothesize that the healthier metabolic profile observed in homozygous c.273_274delAG carriers was mediated by acetate produced by gut bacteria; however, we lack data to firmly verify this hypothesis.

Impact: Our results suggest that sucrase-isomaltase constitutes a promising drug target for improvement of metabolic health, and in a broader perspective add to the debate about the health effects of sugar consumption.

You know, it could be that these people are healthier because they avoid sugar because sugar makes them feel like crap when they get overloaded with aceatate.

There is no evidence that higher levels of acetate are better for people. Because if that as so drinking would be healthy for everyone.

https://academic.oup.com/alcalc/article-abstract/23/2/123/96...

https://www.biorxiv.org/content/10.1101/2020.07.20.212597v1....

>You know, it could be that these people are healthier because they avoid sugar because sugar makes them feel like crap when they get overloaded with aceatate.

They address that hypothesis and dismiss it. It's beyond my understanding to assess their methods, but don't pretend they didn't even mention it.

Where did the study say that? They did the genetic study on mice, not humans. And they only said it gave them a better BMI, which is only one indicator of health.