[revolvingocelot]

I'm no expert either, but I consider the likelihood of distilled water being neutral-to-good to be pretty poor. I can't really imagine naturally-occurring freshwater sources without minerality of some kind, and so I thus expect evolution to "expect" that minerality in water at the organism level.

[Mistletoe]

Rain fits the bill for what you describe.

The RDA for calcium is about 1.2g per day and magnesium is about 420 mg. It's hard to think of a way that the 24 mg calcium (2% of RDA) in a cup of bottled water and 5 mg of magnesium (1.1% of RDA) could have any effect at all compared to the massive amount in food. I guess if you were marginal on your doses of those minerals it could add up, but I can't think of a way deionized or distilled water could actually be harmful.

Disclaimer: I drink reverse osmosis water every day with a ppm of about 8 compared to my tap which is 100 ppm. Rainwater varies but is probably about 8 ppm. :)

[revolvingocelot]

Sure, but nobody and nothing is standing out in the rain to "drink" the majority of their water intake. It's hard to think of any civilizations that relied on mostly rainwater, but maybe I haven't heard of any. What little prehistory I do comprehend suggests that consistent freshwater sources control patterns of human habitation (eg, most capitals are on rivers; Ur is a desert ruin because it is no longer a port city covered in greenery but was once).

Your point about diet is reasonable, but I still think it's probably "easier" to get it right in the water. No need for the body to move stuff to the kidneys if the water's already got some in it!

>Disclaimer: I drink reverse osmosis water every day with a ppm of about 8 compared to my tap which is 100 ppm. Rainwater varies but is probably about 8 ppm. :)

Parts per million of what? Maybe I'm stupid and that stands for "particles per milliliter"?

[nequo]

> It's hard to think of any civilizations that relied on mostly rainwater, but maybe I haven't heard of any.

I think that the Maya mainly relied on capturing rainwater for their water needs. I assume this would have included drinking water.

https://cnnespanol.cnn.com/2012/07/18/los-mayas-resolvieron-... (in Spanish)

https://www.discovermagazine.com/the-sciences/maya-water-sys... (in English)

[quesera]

I'm sure that naturally-occurring water sources will have much higher mineral content (i.e. dissolved solids) than distilled water.

But I'm not convinced that "drinking water" is a significant contributor of minerals to the human diet.

My instinct (not a nutritionist!) is that there are far more accumulated minerals in the plant and animal "apex hydrators" that I eat than I could get directly from water. And I probably drink a lot more direct water than most people do.

The anti-DW "leaching" argument is that you have the minerals in your body already through other sources and accumulation, and when you drink DW (yuck anyway), it has so much capacity to dissolve things that it leaches necessary stuff from you. The counterargument is that most of the incorporated minerals aren't coming out of your organs easily, so DW mostly sucks up bad stuff that you'd probably excrete most of anyway, but every little bit helps. These both seem flawed to me!

[hinkley]

You can explode a salt water adapted single celled organism by putting it in fresh water. The osmotic pressure sucks in water and the cell blows up like a balloon.

I'm not talking about minerals in drinking water being a nutritional supplement. I'm talking about your kidneys not being able to block minerals from leaving in your urine. Any water coming in with absolutely no mineral content means a net loss on the other end.

[revolvingocelot]

>But I'm not convinced that "drinking water" is a significant contributor of minerals to the human diet.

I don't think I'm claiming that. I'm sure kidney functions work so long as some salts get in 'em, whether dietary or water intake, I just suspect that the body expects the minerality to already be in the water directly, because the vast majority of non-human-curated drinking water seems to be that way.