
Milk, orange juice, pedialyte more hydrating than water - uptownfunk
http://mobile.nytimes.com/blogs/well/2016/06/30/milk-and-other-surprising-ways-to-stay-hydrated/
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colechristensen
This is a terrible article about a study with really poor conclusions.

Are you more "hydrated" if your stomach is carrying around fluid for longer?

They test how much healthy young men pee out 2 hours after consuming
something. The problem is, it's a dumb test. That 2 hours is pretty short when
it comes to how long it takes things to empty from your stomach. With a full
meal, your stomach would be a little more than half full at that two hour
mark.

Just water gets dumped from your stomach really quickly, 50% in 10 minutes.
Here's the rub... while it might not be sure based on the study design, it
seems there's a real good chance that the only thing going on here is people
carry milk and pedialyte around in their stomachs longer. That's it. No extra
"hydration" no health benefits.

It would be akin to saying drinking 1L of water right away is more hydrating
than drinking it in small increments over 2 hours. Is it more hydrating? Or
did your body just have less time to turn it into urine?

The big assumption being made is equating "hydration" with how much fluid you
didn't pee out after two hours. If it's not tied to some set of health metrics
(and really if it isn't tied to a long term health study) it should say
absolutely nothing about conclusions an average person should take.

~~~
the_duke
I was going to write a scathing comment about the study, but you pretty much
said it all. This study is really quite pointless.

What suprises me is that anyone with knowledge in physiology would call this
study "brilliant". I would expect better of someone leading a laboratory and
an education in biology. ([http://kins.uconn.edu/lawrence-e-armstrong-
ph-d/](http://kins.uconn.edu/lawrence-e-armstrong-ph-d/))

~~~
colechristensen
From a scientific perspective, the study has plenty of value. Making models of
how what you consume effects gastric emptying and urination patters... I could
see that being super useful for, say, drug trials. How medicine travels
through your digestive tract is important. Basic facts about the body's
response to stiumli is important.

That is... as _long_ as you constrain yourself to only concluding the facts
that are there. How fast your stomach empties and urination schedules ...
these aren't facts the average person can draw any conclusions from.

Good for science, bad for stupid news articles.

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Havoc
>After all, if you drink a cup of water and then immediately excrete half that
amount in your urine, you haven’t added eight ounces to your water supply, but
only four.

Seems like pretty flawed reasoning to me. The aim isn't to keep the liquid
inside of you as "water supply".

Unless you're dehydrated in the serious sense (survival situation, diarrhea
etc) there isn't really any need to drink something special. The body does an
entire satisfactory job of balance electrolytes and getting rid of waste via
urine if you just drink enough water.

~~~
JshWright
Exactly... If you drink 8oz of water, and your kidneys got rid of 4oz, it's
because you didn't need those 4oz (or because your kidneys needed to use that
water to carry other stuff away with it).

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Bromskloss
> The guiding principle behind the new hydration index is that some fluids
> last longer in your body than others

Is that all there is to it? Could it not happen that some drink caused the
water supply in the body to decay as normal, but then continuing to even lower
levels than before, for example?

> Lawrence Armstrong, a hydration expert

One wonders how there can be such a thing as a hydration expert if not even
these basic things have been known until now.

> But don’t forget that milk has many more calories than water, so don’t
> overdo it, either.

A bit beside the point, perhaps: What caloric content is there in water? Can
it be said to have any at all? It makes you think about how to define it,
really. On the one hand, we don't typically think of the energy as coming from
the water, but in the other hand, water must be present for us to extract the
energy from other molecules. In a situation where energetic molecules (but not
water) are already present, then, it is the consumption of water that causes
an increased amount of energy to be made available to our bodies. Similarly, a
battery contains energy, but not until we add cables to connect it do we get
access to it. In a sense, it is the addition of the cable that contributes the
energy.

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MrJagil
Coconut water is supposedly quite hydrating as well and, unlike Gatorade,
natural. It's a shame they did not test it but the reasoning applied to milk
should carry over:

"Why is milk so efficient at rehydration? “Normally when you drink, it signals
the kidneys to get rid of the extra water by producing more urine,” Dr.
Maughan said. “However, when beverages contain nutrients and electrolytes like
sodium and potassium, as milk does, the stomach empties more slowly with a
less dramatic effect on the kidneys.”"

~~~
Havoc
>Coconut water is supposedly quite hydrating as well

Is it? I like the stuff sure, but clever marketing and dubious blogs aside
I've not seen anything supporting this.

~~~
mikecke
In these cases it's extremely easy to get a gist of the research behind a
certain topic by searching PubMed.

[http://www.ncbi.nlm.nih.gov/pubmed/22257640](http://www.ncbi.nlm.nih.gov/pubmed/22257640)

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bemmu
I wonder if this means that a latte would have a better kick than black
coffee, because it would stay in your body longer? Assuming same amount of
caffeine per litre.

~~~
JshWright
It stays in your stomach longer. That's not useful to your body... Fluid is
useful in your circulatory system, where your body can move it where it needs
to be, or get rid of it.

The extra fat and sugar in the latte will stick around much longer...

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the_duke
Link to the actual study:
[http://www.ncbi.nlm.nih.gov/pubmed/26702122](http://www.ncbi.nlm.nih.gov/pubmed/26702122)

PDF:
[http://ajcn.nutrition.org/content/103/3/717.full.pdf+html](http://ajcn.nutrition.org/content/103/3/717.full.pdf+html)

------
ekzy
Interesting to see that they use cow milk as an example while there are, I
suppose, a lot of other drinks where this argument applies. What about plant
milk, tea, coffee, other juices etc...?

~~~
kalleboo
The article links to the study it was based on which tested more drinks:
[http://www.ncbi.nlm.nih.gov/pubmed/26702122](http://www.ncbi.nlm.nih.gov/pubmed/26702122)

> Total urine masses over 4 h were smaller than the still-water control after
> an oral rehydration solution (ORS), full-fat milk, and skimmed milk.

> Cumulative urine output at 4 h after ingestion of cola, diet cola, hot tea,
> iced tea, coffee, lager, orange juice, sparkling water, and a sports drink
> were not different from the response to water ingestion.

I don't know where the Hacker News submission got "orange juice is more
hydrating than water" from.

~~~
hellogoodbyeeee
>I don't know where the Hacker News submission got "orange juice is more
hydrating than water" from.

They didn't just read the abstract like you did. There is a link on the page
you hyperlinked to for the full text

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upofadown
>A score higher than 1.0 indicated that more of the beverage remained in the
body as compared to water, while a score lower than 1.0 indicated a higher
excretion rate than water.

Then solid foods that need to be digested to get out the water would score
even higher on this index. Condoms full of water would have an infinite score
as the water would never show up in the urine. What I am saying here is that
this is a stupid way to measure "hydration".

Speaking of stupid, why does HN have so many of these pointless diet things on
the front page?

~~~
colechristensen
>Speaking of stupid, why does HN have so many of these pointless diet things
on the front page?

People are really interested in their health. Lots of "hackers" would be
super-interested in information that gave them conscious and definite ways to
improve themselves.

The problem is that there's very little real information out there.

This study, if were framed properly, would have been at least mildly
interesting.

Stomach emptying of fluids depends on the type of fluid... urination frequency
too. Thirsty but don't want to pee all the time on a road trip or hacking
marathon? Drink milk! Hack your body!

But instead they had to link it with "hydration" which is bollocks. It's not
clear that anyone should care at all about hydration unless vigorous exercise
or extreme heat is involved because your kidneys do a pretty good job, period.

~~~
agumonkey
self hacking the ultimate hacking ?

~~~
dogma1138
Body hacking, biohacking, neurohacking...

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JustSomeNobody
Wow. Whodathunkit? Humans have been walking around dehydrated for tens of
thousands of years.

Definitely sarcasm.

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miguelrochefort
Milk and orange juice? That's the basis of Ray Peat's anti-inflammatory diet.

He advocates drinking one liter of each every day (to which salt and sugar is
added).

~~~
JustSomeNobody
Because that won't hurt your pancreas at all. /s

~~~
miguelrochefort
He doesn't seem to think that would.

He says that polyunsaturated fatty acids are the cause of most diseases.

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Jabbles
Did one of the experiments involve drinking a litre of coffee?

~~~
Bromskloss
Yeah, but not the test subjects.

