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Comment by ampdepolymerase | Hacker News Reader

It would be interesting to see whether the sweet taste is because of pure coincidence or whether it is because a small quantity of heavy water confers an evolutionary advantage.

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Indications are that it's generally bad for eukaryotes: https://en.wikipedia.org/wiki/Heavy_water#Effect_on_biologic...

Another thing that tastes sweet is lead paint. That did not work out well.

Lead isn't good for the brain or nervous system, but does it have any benefits?

Some poisons for example help disease resistance because the disease pathogens are harmed even more by the poison than we are.

We do not know of any, either in humans or animals.

Evolution doesn’t need mutations that give perfection just an advantage on average. How much does lead paint occur in the environment humans traditionally evolved in?

Nonetheless, there are proteins whose role is to bind and sequester lead, which means there was some functional selection to avoid lead toxicity.

Also antifreeze, which dogs unfortunately find irresistible.

It's coincidence. Our ancestors didn't have access to heavy water.

Heavy water exists naturally. It is reasonably common, and since it has a different density there might well be natural or biological processes which might concentrate it...

I'd be curious at what concentration people can detect heavy water. My guess is that this concentration does not occur naturally, but I could be wrong.

I'm betting the latter. Consider that lead also tastes sweet[1], that's why kids would eat lead paint. Our ancestors were never placed in situations where eating either lead or heavy water could change evolutionary outcomes because these substances are not easily obtained in high concentrations in nature.

[1] https://www.thoughtco.com/sugar-of-lead-3976065

I assume you mean "former", not "latter"?

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