Human taste buds can tell the difference between normal and 'heavy' water
sciencealert.com
sciencealert.com
> In tests with mice, however, the animals did not seem to prefer drinking heavy water over regular water, although they did show a preference for sugared water – suggesting that in mice, D2O does not elicit the same sweet taste that people can perceive.
I was reminded that rodents also can’t taste aspartame[1], and that in general human taste buds are more finely-tuned than many other mammals (we can detect isomers and many complex bitter chemicals, whereas many other animals can only do the amino acids, sodium, and simple carbohydrates).
Having never drank it myself I was wondering if the sweet taste of heavy water is distinctly “artificial” in the way that sucralose/aspartame/etc in water is immediately distinguishable from regular sugar.
A lot of the smell sensitivity comes from ("carefully tuned?") positive feedback loops int the olfactory systems which amplify small signals.
Or something like that, supposedly. Not my area. At least, not the input side. On the output side of stink, I'm no theorist either; maker, for sure, though!
Within humans there is considerable variance among bitter tastebuds. Roughly speaking, the salt/sour/sweet tastebuds are comparatively simple ion detectors: salt = sodium, sour = hydrogen (from the acid), and sweet = glucose. And yes, sweet is more complicated, because it’s trying to detect a more complicated form of aquatic solute. But the idea is that these tastes are trying to find a specific and well-defined chemical property.
Bitterness is different. Bitterness is basically a poison detector, which means that to be effective it needs to register a wide variety of potential toxins. So akalais/bases tend to be bitter because naturally-occurring bases tend to be toxic. But there are all sorts of complex organic molecules that may be toxic (or are chemically very similar to toxins), which some people can taste and others cannot. Cilantro is probably the most famous example: people who hate cilantro are tasting a (harmless) toxin that other people can’t detect. But this taste is a true taste from the tastebuds, not a smell.
Possibly there is a dangerous chemical out there found in berries/leaves/etc which is structurally similar to linalool, enough to fool certain types of bitter tastebuds.
As a kid, I used to get stomach aches and a long list of other issues. Fast forward after a bunch of tests as an adult and the results reported to me by a doctor spelt out that most artificial sweeteners are effectively poison to me. If I want a headache, stomach ache, etc I just consume one of the many sweeteners out there.
The "hyper-sweet" taste and after-taste I get from most artificial sweeteners for me is a signal of poison or bad food. Its a clear signal to avoid that food in future.
My question is the same: I wonder if D2O would have that same kind of "twisted" sweetness?
Secondary questions: I wonder if our ancestors did the same? Noticed that they didn't feel well and that was enough to tip the selection balance such that we now have the ability to detect D2O? How subtle would that effect be? or is just it tied into a specialised "anti-poison" set of structures we've got to detect bad-food? I think this is more likely. D2O is bad water. We have senses for other kinds of bad water as well.
Though I suppose any fan theory in this direction could be salvaged by the conjecture that talking mice are different.
Edit: The taste was definitely different but not enough so that I could say it wasn't placebo
https://www.youtube.com/watch?v=MXHVqId0MQc
TLDR - sweet, has an aftertaste, feels cold on the lips (compared to regular water)
For example marketing and sales don't exist yet per academia's opinion...
It seems that Cody’s video inspired the research.
It's a really nice nerd content channel with science of lots of different areas!
Then it went to him recollecting the heavy water that has passed through him. Which is very Cody, but also, well, gives off strong Howard Hughes vibes.
Cody is a heck of a smart person, but then does some pretty questionable stuff. His mercury vids are a good example. Like, I believe him when he says that if you don't have open wounds, you can slosh mercury about in your mouth safely. But for the life of me, I just can't think it's actually safe.
Or the time he was sweeping the center median of a freeway at night trying to collect platinum dust from catalytic converter exhaust. Yeah, it was under the lights, but daytime would obviously have been better.
Or his noble gas vids. Inhaling them seems safe per his description, but the vibe is just so, well, not safe.
A lot of his vids are like that. It feels very early-1800s-chemist, back when they had to taste all the reactions cuz they didn't have pH paper. Like, it all has to be sensorial for him/the views.
Great guy though.
Summary of O16, O17, O18 formation inside massive stars, here:
I wonder if D2O(18) would have any flavor difference...
My understanding is that, at least during WWII, Norway had a bunch of hydro power they used for electrolysis to produce hydrogen in order to produce ammonia via the Haber process. Deuterium is accelerated about half as strongly as regular hydrogen in the electrolysis cells. If you connect up your electrolysis cells in series, the small gradient in hydrogen isotopes you get across each cell accumulates across the cascade, and also the regular hydrogen leaves as a gas at a higher rate. At least that's my understanding, which would also imply the end of the cascade that's depleted of deuterium is also enriched in heavy oxygen isotopes.
BTW: "New York City department of environmental protection is one of the 5 municipalities in the US that is allowed to supply unfiltered water based on their water quality, and the water is well known for its fresh taste (which is based on the absence of chlorine, a chemical often used for water treatment)."
"New York City drinking water springs from 125 miles away in the Catskill Mountains -- 90% of the water comes from the Catskill/Delaware watershed, where waters from tributary rivers collect in 19 reservoirs. The other 10% comes from smaller watersheds in Westchester and Rye -- all of it traveling through vast underground aqueducts to supply the city’s residents."
In general mountain water I think is the best.
People don't really think about it this way, but New York is actually very close to two mountain ranges (the Taconic range of the Appalachians, and the Catskills). The Taconics are the dramatic peaks you see when crossing the Hudson a bit further north around Newburgh, and the Catskills are the much larger mountains slightly more inland.
It would be interesting if in your cases it was high deuterium water though. It's not something I ever considered really.
Of course when straight groundwater is your best or only option, that's a hell of a lot better than having no source of plausibly safe water available. I've drank lake water where we would just disinfect it with a few drops of bleach for a couple of weeks when on trips. But was always told that this is a short term solution for convenience.
The wells here are typically 50m+ meters deep, so if you have a 1 inch connection that's more than 25 litres just sitting in the pipe. For longevity you don't want to run the pump every time you turn on the tap, so there's usually a pressurised tank with another 25L or so and a pressure controlled switch in the pump.
So if you want to get 'fresh' water you first need to run 50L through the system. There's also the issue of extra minerals - the water here has a lot of iron, which turns everything red unless you have a good filter. The filters will have a low flow rate, so you need another tank to store the filtered water. Much easier to just get a RO system or bottled water for drinking :-)
50m of earth is going to produce some of the cleanest water you've ever had, unless of course there is pollution from heavy industry nearby. I know a few people who collect water daily from springs and drink that as is. If you lookup DIY water purification systems they typically have one plastic tank filled with sand and another with charcoal which filters pretty much all of the stuff out you don't want to drink.
>Experiments with mice, rats, and dogs[42] have shown that a degree of 25% deuteration causes (sometimes irreversible) sterility, because neither gametes nor zygotes can develop. High concentrations of heavy water (90%) rapidly kill fish, tadpoles, flatworms, and Drosophila. The only known exception is the anhydrobiotic nematode Panagrolaimus superbus, which is able to survive and reproduce in 99.9% D2O.[40] Mammals (for example, rats) given heavy water to drink die after a week, at a time when their body water approaches about 50% deuteration.[43] The mode of death appears to be the same as that in cytotoxic poisoning (such as chemotherapy) or in acute radiation syndrome (though deuterium is not radioactive)
I think sinking ice cubes would be a fun party trick.
(Note, if you put too much dry ice the water in your drink will freeze and that can affect the taste quite negatively..)
For better sinking ice, mix deuterium and oxygen-18.
For the best sinking ice use super heavy water[1] (substitute tritium instead of deuterium) although it is toxic: “The median lethal dose (LD50) of tritium assimilated by the body is estimated to be 370 GBq (10 Ci). Higher doses can be tolerated with forced fluid intake to reduce the biological half life.”
One of the videos linked by other comments mentioned that they spend $1000 on a tiny amount of O18 to see if it would also taste sweet. Ice cubes made from that seem to be the kind of party trick best reserved for celebrating your first billion.
But also note your body already has to be robust against it to some degree, because water will normally have a certain amount of heavy water in it naturally, so it's not like it's a deadly deadly toxin. It's just something you shouldn't drink a lot of.
In the same paragraph they say "All research procedures were ethically approved by the Committee for the Use of Human Subjects in Research" at their university, so they probably had to provide a lot of evidence that it was safe beforehand.
[0] https://www.nature.com/articles/s42003-021-01964-y#Sec10
Some poisons for example help disease resistance because the disease pathogens are harmed even more by the poison than we are.
https://sciencenotes.org/can-you-drink-heavy-water-is-it-saf...
If you replace 20% of your cellular water with heavy,
you gain about 1.7% of your weight maybe (water being ~80% of you).
I see an angle here for a boxing thriller.
"Joe, this taste I dunno, sweet to you? No? Huh."
https://www.chemistryworld.com/opinion/the-last-retort/30055...
But the most interesting part is when they tested it on mice. Mice are small and it doesn't take that much for heavy water to start having an effect. And what they noticed is that after some time, mice shunned the heavy water in favor of regular (light) water. Suggesting that mice are able to taste and recognize heavy water as harmful.
By the way, that video is excellent. Thunderf00t is a troll, but when he stops ranting and starts doing science, he makes really great content.
He has some strident opinions on things outside his field (for example he's got a big problem with Christianity) but does that actually make him a troll?
For a hard scientist, that's almost a given. He'd be a lousy hard scientist if he didn't have a big problem with it (both when it comes to internal contradictions and in the mismatch with the real world).
It is not his opinions, and in fact, I mostly tend to agree with these. It is more about if he disagrees with someone, he is going to lose all objectivity and attack him like a rabid dog, backed by all his fans. It is surprising considering that he looks like a competent scientist and promotes rationality.
For example, it looks like he has a grudge against Elon Musk for some reason. No problem with that, I am a bit of a hater myself. However, some (not all) of his argument are simply wrong, or at least incomplete, and he repeats them over and over, mixed with movie clips meant to ridicule, and he never backs down.
Even when it supports my ideas and I enjoy two minutes of hate as much as anyone, I think it is toxic. The only purpose I see to these videos is to reinforce ideas people already have and turn them into zealots instead of educating others. Not so different from the cults he denounces.
And it is a shame because SpaceX is awesome and I credit Tesla for making electric cars people actually want to drive, and PayPal served me well in the early days.
I also find those videos very grating and tiresome. That’s not entirely his fault though, some of the videos he excerpts from are themselves dreadful. Leaving that part aside, the mocking tone he adopts just isn’t necessary.
On the other hand, when he’s presenting an actual technical topic his videos are great.
There's a lot of cringey comments and statements in that video that are just hilariously wrong I thought it might be satire at first. Apparently you can't put steel in contact with concrete because a tiny whiff of surface corrosion is going to seriously risk the integrity of that 3/4" thick steel pipe... Not to mention claiming that clearly they didn't account for linear expansion of the pipe right after poking at the linear bearing material and saying it looks like they put it on some type of plywood.
That video is 20 minutes of him spouting off the same kind of nonsense and trivial mistakes that he spends every other video deriding other people for making. He even makes some mistakes that are basically just pure physics, which he of all people should know is suspicious on the face of it. He claimed that if a test vehicle failed to slow down and impacted the far end that it would rupture the test track. It's a 3/4" steel pipe with a massive thick door and the inside being at a weak vacuum, it's not coming off. Not to mention his differential heating claims which would not change with length given that the test track can obviously resist the bending with just the weight of the tube elastically deforming it to keep it straight.
His own zealotry on some subjects blinds him to his own obvious mistakes. If it was someone else making a video with so many errors he would be all over debunking it.
https://www.quantamagazine.org/a-new-spin-on-the-quantum-bra...
Off-topic: Is anyone else reminded of that episode of Hogan's Heroes where the Germans store heavy water in the POW camp to protect it from allied bombers, and Hogan tricks Colonol Klink into drinking the heavy water by telling him it had some kind of health benefit? https://www.pinterest.ca/pin/584201382887878852/
In certain cases and depending on the person, human taste and smell is an incredibly accurate chemical detector. https://www.sciencealert.com/this-woman-can-smell-parkinson-...
Low pressure, extremely hard to the point where soap is useless and we had to replace things regularly from scale build up, the UV filter thing we had to run in the basement, the worry that one day you could randomly lose the prime on the pump and they'd have to dig to get it back (which happened once), no fluoride so my teeth aren't the best.
Give me that carbon filtered (removes the chlorine taste) city water any day :)
I think a common misconception is that your water runs through the salt. In reality, the water runs through a filter and the salt water is used to periodically flush the accumulated metals out of the filter. This could lead to some residual salt, but it will get flushed away quickly. The other source of salty water is a busted valve. Replace it and the water will be fine again.
Where was this? Pumps are placed at the bottom of wells and avoid this problem entirely. It's physically impossible for a pump placed at the top to raise water more than 10m.
Toronto has chlorine plants and ozone plants.
(And from my darkroom days, I'm fairly good at nailing 20 °C with my fingers, so I just waited for the tap to give me the right temperature and then poured it straight into the pots.)
Seattle has fantastic city water. Most months of the year, Oakland water is very good (offer not valid for all combinations of reservoir and pipes, your mileage may vary).
Also, if you got used to something like iron or calcium enrichment, you might just not like those vintages, even if they're "objectively" good.
My dad commented specifically that he was impressed at the taste of our tap water, and thought it was an unexpected highlight of the trip.
We grew up on well water. Although by this point they were living "in town" so it is possible that their water has more chlorine, etc, than Toronto's. When I visit them, their tap water tastes dull (but not bad) to me, so there is that.
people disagree with any water that tastes different than what they are used to and assume its bad. that's pretty much all it comes down to.
Really, up until a few generations ago, people tended to stay put and a family might drink from the same set of water sources for centuries. The only reason water would ever taste different is if something bad had happened to it.
We knew that our taste buds (and smell receptors) are incredibly sensitive to small amounts of chemicals. It's somewhat unexpected that they could distinguish molecular weights.
It may tie in to the Vibrational Theory of Smell:
https://en.wikipedia.org/wiki/Vibration_theory_of_olfaction
The standard theory of odor is that it's a lock-and-key process, like the immune system (and related to it). But there are some odd holes in that theory, like why sulfur compounds smell "alike", even though they're different keys fitting different locks (and we can't even exactly say what "alike" means).
This one guy suggests that it acts like a spectroscope, sensing the way atoms vibrate within the molecule. It's a brilliant theory that explains a lot of stuff, except that it's completely insane and there's nothing even vaguely like a biological mechanism that would enable it to work. He tried testing it with molecules that substituted deuterium for hydrogen, which alters the spectroscopic signature -- but got mixed results.
Smell and taste are only distantly related as mechanisms (taste is actually several very different mechanisms, and that's well-documented). This suggests that there's even more to it than that. Does this bring Luca Turin back? Dunno. He seems to have abandoned smell research entirely.
Deuterium is so much heavier than regular hydrogen that the bond lengths in D2O are shortened by enough (~3%) to affect cell chemistry. Also significant differences in boiling points and other physical properties.
if someone making a sandwich puts mustard on a sandwich and uses that knife to cut my bread, I can taste the mustard even though they wiped the knife. the % of mustard on my sandwich has to be very, very small.
I hated that entire room and what it stood for. Philistines masquerading as professors. No scientific talk which was done systematically should be laughed at like that.
To me it reinforces the one correct reason to become a professor: you want to raise the standard of professionals / colleagues in the field by mass education. Your goal is to increase quality across the board, and the only way to be successful is to be a good and engaging communicator. There are networked benefits from creating success for your students.
E.g., now that it turns out that saturated fat is wholly harmless, the past five decades spent failing to investigate why meat consumption really causes circulatory disease is practically criminal. How many early deaths are traceable to this sustained failure? How many, to having continued permitting trans fats in stuff sold as if it were food? How many to oxidized unsaturated fats?
People like to insist that science always gets it right in the end, but these corrections are always isolated flukes. The pattern suggests a clear majority never get corrected.
mRNA vaccines are just such a fluke; their inventor spent her whole career being spit on. How many died, for lack of mRNA vaccines in past decades when the method could have accelerated vaccine development by years back then, instead of only now?
A great fount of suppressed truths must lie dreaming in the work of women and minorities driven from their fields.
But of course detection would be possible, it has been known for many decades that different isotopes change reaction kinetics (https://en.wikipedia.org/wiki/Kinetic_isotope_effect). That is a measurable chemical effect, so of course a protein could make use of it. This is something I was taught in university, so this is not any kind of obscure knowledge, but mainstream chemistry.
Just that the fruitfly (or some parts) could be used; I imagine the fruitfly is more of a canary than a detective.
Source: Dating.
And by conventional chemical wisdom D20 and H20 are virtually identical: the electron structure is the same and that basically dictates the chemistry. The only significant difference is the mass of the molecule (about 10% heavier), and experiments with oxygen-18 water (which has the same mass as D20) showed it doesn't taste of anything, so it must be due to very slight changes in structure between the two.
Many of the most poisonous berries are sweet. Belladonna is extremely sweet.
Much of what is bitter (basically every non-sweet plant out there) is harmless.
If you judged the safety of food by taste, I’m afraid you wouldn’t last long in the wild.
But is this a pattern because humans, like other species, find a niche where they can consume something that makes other life forms sick?
It's always an advantage to be able to benefit from something others can't, so you're not in direct competition.
It is always advantageous to be an omnivore. The more things a creature can consume, the more it will reproduce and the more ‘niches’ it fills.
Cockroaches, flies, bacteria, and — through the use of intelligence that enables turning virtually anything into nutritional energy - humans.
There is never an ‘advantage’ to limiting ones foods.
I agree in theory, if there were no tradeoffs required to consume any particular thing. But my comment took for granted that there are. Even for really versatile species, there are to some extent.
I've lived in multiple San Jose homes now, including SJSU dorms, and in every one of those, the water came out of the tap cloudy and if you let any dishes/silverware air dry after washing, they have a significant amount of white precipitate on them that becomes impossible to clean off without some kind of mild acid, like vinegar. At my parents house you can get water spots on things but they're typically quite light and easy to clean off.
In addition to that, the flavor just tastes very wrong in San Jose. I lived in SJ for 9 years and never got used to it, either.
There are some sites that have PPM ratings for different cities in California and it seems like San Jose consistently rates as one of the highest.
edit: I was mistaken, please disregard.