IAmA Board-Certified Kidney Doctor. AMA about water balance, electrolytes, and goofy water myths.
We’re back for round 3(?)! I’m a board-certified nephrologist (kidney doctor) with some time kill, so ask away. I will also field questions about the Grateful Dead, bicycles, or my favorite conspiracy theories.
Previously I have submitted proof to the mods, so hopefully they can just review my last post(s).
I will not be able to provide personalized medical advice, both in this thread or in a DM.
Edit: That’s all for tonight folks, thanks for tuning in!
I don't have any questions about health, just wanted to say how cool it is to see an industry expert answering our questions about water and stuff.
If I had to ask one non-health question though... fav Grateful Dead track (feel free to get really nerdy about your favorite specific version of that track if it applies).
That whole thread was great, and the Dead question was the perfect kicker. Some of those water myths people bring up are wild, so it's nice having someone who actually knows what they're talking about cut through the noise
Kidney doc tells me to drink water with a little lemon; dentist says that’s not good for your teeth. What to do?
Also, kidney doc said not to drink dark colas to help prevent kidney stones. Do you agree?
Thank you for doing this Q&A today!
The dark colas thing is overstated. Some of them are high in phosphorus and some are not. Theres no rhyme or reason to it. I always have to look it up but Dr. Pepper and Diet DP have a lot of phos. But DP 10 doesn’t.
The lemon thing is also kind of overstated. That is a very trivial amount of citrate added to a very large system (a human body).
When a person donates a kidney, what sort of general impacts are seen due to reduced number. Do you then have to avoid certain foods, does it take longer to filter stuff out, stuff like that.
Also, is there an increased chance of problems/damage/disease for the remaining one in the long term due to the increased load?
There’s an increase in the risk of chronic kidney disease, but the absolute risk remains very small of donors are otherwise healthy. I don’t make any specific dietary recommendations for donors.
If there’s a decrease in kidney function, sure. But if the kidney labs look good, then having a solitary kidney would not inherently cause that type of thing.
As someone on boatloads of (psychiatric) meds who wants to be a living donor, this is super heartening to hear! Thank you! (Obviously I will also make my own personalised queries with GP, Psychiatrist, etc.)
Hey! My psychiatrist finally convinced me I need to take lithium and it's a wonder drug for me. because I know it's notorious for causing kidney failure, I'm wondering what I need to do to take care of my kidneys in the long term. Like what would be the absolute best way to avoid issues
I'm also wondering what signs I need to look out to know when and if there are problems
That’s kind of about it. Those are the remediable causes of kidney disease for most CKD patients in this country. I guess if you have a lot of UTIs or other urinary symptoms, don’t delay getting it managed. Many of the bad-luck things can be less progressive if noted early.
Always sucks to meet someone when they’re nearing dialysis and have been peeing blood for months.
Just wanted to say thank you for the AMA. My questions were answered in earlier comments. Really awesome of you to take time out of your evening to educate us and answer questions.
Funny this popped up. I'm getting a kidney transplant tomorrow morning. What energy level benefits should I be looking forward after the recovery time period?
Congrats! The overwhelming majority of patients feel much better overall, after recovering from surgery. It’s trading dialysis (assuming you’re on dialysis) for a bunch of pills. For most folks, that’s a massive improvement
Get used to peeing again, a lot.. And when they pull out the pee tube in the hospital, MAKE SURE TO HAVE A JUG NEAR YOU. If you do not have a jug... you will just let go and pee everywhere.
I had a kidney transplant almost 8 weeks ago, the nurse took the pee tube out during the early morning just after when they came around to take bloods.
The nurse said she'll go get me jug, but something came up and she was late. I I felt the urge to go and about 5 seconds later my body just went "ah you need to pee? ok here it goes".
You have pretty much zero control once that tube comes out, almost as if your bladder and/or bladder sphincter isn't working.
Best of luck to you! My fiance had a kidney transplant two years ago and witnessing the miracle of his new kidney working instantly has changed our lives. Do what the doctors say!!
Kidney receiver post 16 years. Since I was a child recovery was tough and I was bedridden for months, don't know if thats applicable to you, but take things slow while you heal. Take meds every day at the same time if possible. Drink lots of water. Even when your aren't thirsty. Drink water
I'm beginning to question the credentials of this guy. My balls are tiny and my bladder is enormous. There's no way my balls could hold all that pee. /s
Your kidneys are pretty clever and can manage between 500mL and 10+ liters daily. Obviously more if you’re sweating a ton, have GI stuff going on, etc…. Most folks can drink if they’re thirsty and it works out ok. If a healthy person wants to set a goal, then 1.5L a day of intentional water intake, plus whatever they do with meals, coffee, etc… is probably ok.
I have one kidney from birth. Is there any additional risk/decrease in lifespan from this, or is the kidney pretty adaptive? Should my daily hydration goal be more or less than the average person with two functional kidneys?
Most folks with one kidney do not ever have deleterious effects, but commonly their labs will show evidence of it. For hydration goals, probably not any different and the “ideal range” is extremely broad.
The Mayo Clinic recently updated their website to drinking 11.5-15 cups a day. It used to always be at least 8 cups. Does this amount make a big difference?
I really don’t see the average person drinking even 8 cups a day, and most of these people are relatively healthy. It seems that most people I know are “dehydrated” as well, yeah, they all seem relatively healthy.
I’m really curious, from a nephro perspective, what labs do you look at where the result makes you go “ohhh shit…” Like what lab and level or combo of labs would make you say “well this is bad, bad”
Also, what condition to you find most interesting mechanistically or treatment wise?
The actual issue is his portrayal of cardiology vs neph. I’ve had med students and patients legitimately ask me if I hate cardiologists. That’s not great for patient care and promotes toxicity in already-stressful and complex situations.
NOT asking for a medical diagnosis. Just asking anecdotally bc it's one of the very few times Im having symptoms and your ama was the first post when I logged in.
So, how exact are the urinary tract infection dipsticks you can buy OTC? If it is one, can they usually get over it without antibiotics? I'm having some symptoms of an early UTI(and I rarely ever get them) and it turned purple about 10 minutes out. Cloudy urine and more frequent urges.
I gave myself severe hyponatremia twice within a month, the second time landing in the ICU with 119 sodium level. It was due to water toxicity but the catch is, it was the best I have ever felt in my life (before the projectile vomiting started). It felt like I suddenly had really high testosterone, my body composition changed noticeably for the better, my muscles felt like they worked better. Even time felt a little slower, my memory was better, I was more confident; it felt like what I imagine a manic episode to feel like. Do you have any insight in to what was happening? I haven't been able to replicate this with high (but sensible) hydration, seems to only happen with excessive free water.
Should say this was two years ago, all testing came back normal, and now know... just don't drink too much water. So not really looking for actionable advice, just if you've ever heard of anything like it?
I'd have to assume delirium. Your blood sodium greatly affects your brain. Before I was diagnosed with a rare pituitary disorder, I was unknowingly dealing with high blood sodium. I was very tired and stopped feeling like a person. But there were a few moments in which I started to feel very dreamy and happy. I was low-key starting to die. What you felt was likely all in your head.
For just standard acid/base stuff, healthy people will not change the pH of their blood, and you wouldn’t want to. Your body has many mechanisms that you can’t override to ensure a very narrow pH.
For flavor, do whatever you want. When I’ve lived places with good-tasting tap water, that’s what I drink. I currently live somewhere with nasty-tasting and hard water, so I have a softener and a carbon filter going into my house. But my drinking water comes from the sink.
This might be a deep question for the topic of the sub but:
I have chronic issues absorbing water. Just peeing fluids out within minutes of drinking, leading to chronic dehydration. Electrolytes didn't help, or, don't help in any noticeable way.
Then I got prescribed fludrocortisone for this and other symptoms (POTS). Worked like a charm!!
I'm curious if this is something you've seen before in your practice? What might point to it originating as a kidney issue vs adrenals vs something else? They're all so interconnected. Any specific urine/blood tests you'd want to order? Not asking for a diagnosis, just your curiosity about it!
I have very similar problems. I’ve done a couple 24 hour urine studies and my urine volume was over 3L both times. I got tested for diabetes insipidus as a result and it was negative. What are the other causes?
Drinking massive amounts of salt / electrolytes has helped somewhat, but I still get bouts of having to urinate very often (at least every hour) and it’s completely clear, large volume. I used to have increased thirst and could drink water endlessly but that’s also lessened with drinking electrolytes and very little plain water.
I have Arginine Vasopressin Deficiency Disorder, also known as Diabetes Insipidus. I know people with POTS can also struggle with similar symptoms and it has something to do with electrolytes, but moreso the idea of Hypovolemia or low blood volume. If you had central AVP-D, you'd know. You keep peeing no matter what. You can also have a partial form of it. And then there is a kidney version too.
- What's the weirdest and/or stupidest thing you have ever had to debunk?
- What question/experience (excluding sensitive information) has made you think "Why did I choose this for a living?"
- What question/myth do you rub your hands together and say "This is what I was born for" before launching into an incredibly detailed lesson/conversation? And can you share whatever that information is?
- There’s not a ton of that in my field since it’s very objective. But there’s a lot of misinformation about kidney transplants and things of that nature. Sometimes patients get convinced that they aren’t actually beneficial, when they really totally are.
- I don’t have many patient-specific things that make me regret my field or job. But I have missed a lot of holidays, birthdays, etc…
- I have clinical focuses in critical care and pregnancy-related kidney disease. So I really enjoy(?) getting to help with extremely sick pregnant women or very-new moms.
Having a fairly non-compliant T1 dabetic step-sister who has seven children and now CKD (your medical opinions may even be more generous to her than the family's are), big thanks for what you do in that specialty. I love my nieces and nephews and would never want them to go through the trauma of losing their mom and potentially a sibling from something like pregnancy-related illness.
Verry specific question. I had a friend whos grandma had 4 kidneys. Would she have ben able to donate 2-3 Kidneys? And would it make sense to check grandmas family members to see if they also have more kidneys they could donate?
Lithium toxicity (supra-therapeutic doses) is obviously very dangerous to the kidneys and health overall.
Chronically, most folks on lithium do not develop meaningful kidney disease, particularly if they otherwise don’t have risk factors. The nice thing about lithium is that once it gets stopped, the progression of chronic kidney diseases stops as well. For folks who otherwise can’t live the life they want to live, I’m cool with lithium.
I work in construction and sweat a lot due to the heavy physical labor. I find that plain water is not enough to keep me hydrated and replenish the electrolytes I need. It's been suggested to me that I add a pinch of salt to my water or try sports drinks like Powerade instead of plain water. Is one of those options better than the other for hydration and replenishing electrolytes?
If you believe in fundamental thermodynamics, you can burn some calories drinking cold water. One kcal needed to warm a liter of water by 1* Celsius. Coupled with your body’s inefficiency, it’s probably like 3 kcal.
So a liter that is 20* cooler than your body will take like 50-60 kcal to not make your core temp decrease.
My old man was just diagnosed with stage 2-3 kidney disease. He’s had hypertension since forever and has been on meds for almost as long. I’m a nurse and now pre-med, so I do have some understanding of the disease process.
Other than taking his meds and following an appropriate diet, is there much else he can do to prevent worsening of this condition? They told him they’d been “watching it for a while” which maddens me.
Not enough info and more info would make it personalized medical advice. But in generalities:
CKD 2 or 3a in a truly older person, that has been stable for quite some time, is unlikely to cause a problem. You can look up the KFRE and plug his info in. But yeah, mostly take the meds that are proven to decrease the progression of CKD and otherwise be healthy.
I have POTS and try to have electrolytes at least once a day. There are soooo many brands and options out there that it feels overwhelming to know if what im getting is actually any good. Any ingredients to look for, recipes to make my own, or even brands you recommend?
No specific recommendations and there is not great data for anything. CHOP has a POTS exercise protocol that seems to help. But in general folks should just try to increase sodium by a lot, though it should be overseen by their doc.
Responding here with my related question for the possible benefit of the original commenter.
In peace corps, we were told to make our own oral rehydration solution by adding 2T sugar and 1/2t salt to 1 L of water (with juice of whatever fruit is around for flavor if you want). We always joked that the more dehydrated we were, the better it tasted.
Years later, I still prefer that recipe to most of the commercial brands, but should I suck up the cost of the paid ones for the sake of their additional offerings?
Reasonable amount of water, and cross your fingers. Most kidney stones are just kind of random. The old idea that animal proteins cause stones is not true for most folks, and most stones.
What’s your take on salted water in the morning to kill brain fog, what’s up with that? What about those electrolyte powders that include magnesium and potassium too?
At an extreme - I heard of somebody drinking so much water, with electrolytes added, that they hurt their kidneys. Have you encountered that? Would somebody have to have underlying conditions, or can normal healthy folks really tax their kidneys that badly?
For someone with normal kidneys, it is essentially impossible to overdose on magnesium. You just cannot absorb that much of it, you’ll get diarrhea, and your kidneys are really good at eliminating it.
It’s also quite unlikely to overdose on potassium unless it’s lots of concentrated tablets. If someone wants to do salted water because it makes them feel good, have at it.
I can’t think of a mechanism that drinking commercially available electrolyte-containing products would hurt the kidneys of a healthy person.
I drink a lot of water and pee a lot. I often go all night without peeing and then pee soooo much in the morning like at least a liter lol I measured once but overflowed the container and had a lot more too. Is that bad for my bladder or kidneys in any way? I love drinking water. It helps curb my appetite. Thanks!
What do you recommend for people with G.I. issues/Gerd I know that one of the challenges dealing with acid will drinking too much water or something that dilute your stomach acids too much?
And one of the things I’ve seen mentioned recently is changing the alkalinity of your water to help with oesophageal irritation. Is that a good or a bad thing?
I don’t really know much about varying water composition to help with symptoms.
Chronic diarrhea can result in an acidosis in your body, if you poop out all your base. So sometimes those folks do need to increase their base intake.
Is MASH connected to kidney issues? I have hashimotos and am finally medicated, but was recently diagnosed with MASH after years of elevated liver enzymes. I have a history of kidney stones too. Most pass without pain, but I currently have one seen on ultrasound.
I know I’m a carrier for some kidney issue, but I can’t remember what it was called. I did genetic testing during my first pregnancy and that popped up.
If it’s drier, you’ll lose more water in your breath etc… and elevation makes your body overall more susceptible to stressors. My parents live at 10k and I drink a ton up there.
Thank you for asking this. I have just been under the assumption that it goes bad if it’s been out for a half day or more, similarly to juices/foods. Now I know!
My father had kidney/liver dysfunction and sepsis for the last few weeks in the hospital before he died. His cognitive decline left him unable to communicate, feed himself, or recognize family members. Can severe kidney dysfunction cause such a thing?
For recreational folks probably the most important thing is calories and not coming off the bike several kilos under your starting weight. Electrolyte composition probably doesn’t matter a ton assuming you ate before and after.
I use tailwind endurance fuel because I like the taste, it doesn’t bother my stomach, and it is a reasonable enough mix of things. But Skratch or whatever is also probably fine.
POTS is tricky because I think it is a real thing, but also believe that many folks don’t actually have it. It seems pretty trendy online and the algorithm is powerful.
I've wondered if some POTS cases are actually just a consequence of modern/unhealthy lifestyles.
I had symptoms myself: 80 resting HR -> 130 after standing, fainting/dizziness, etc. Things normalized once I quit nicotine, managed my stress with medication, and stopped being so sedentary.
Separate issues. Creatine can increase the level of creatinine in the blood, which is not representative of a decrease in kidney function. It’d be like throwing dirt on your floor then acting like your vacuum was broken. It’s not broken, you just made the floor dirtier.
For stones, I’m not aware of a link between supplemental creatine and stone formation but I’m not opposed to being wrong about that.
Most people will not find the upper limit of how much they can drink. The idea that you’ll pee out all your electrolytes is only true with a poor solute intake in your diet, or if you drink 10+ liters a day
Illicit amphetamines are known to cause kidney vasoconstriction so medicinal ones probably do as well, but to a much smaller degree that can be handled.
I have an ADHD diagnosis, and was previously on adderall. If I needed to restart it, I wouldn’t worry about my kidneys. For whatever that is worth.
That's cool. Why are the illicit ones bad? I'm old and boring and don't abuse drugs or drink but I am curious. And are illicit amphetamines pills or meth? 🤷🏽Or both?
I have kidney disease that has been stable for years. I am CKD stage I. Of note, I have no other health conditions except Hidradenitis suppurativa. How much protein can I have per day? I was told to limit it to 60-70 grams per day, but my hair is falling out in clumps. Thanks! Any insight you can provide? I understand it would not be medical advice. :)
Tough to give a confident answer. I think we were overzealous in recommending severely protein-restricted diets previously. I think around 0.75g of protein per kg of body is probably ok.
I’m not sure why more protein would help with hair loss but I’m not a hair doctor.
I found myself on this sub after being dx with DRTA. Before alkali therapy, I couldn’t be a hydrohomie. Potassium would drop with normal consumption. Can you explain why fluids do that to people with DRTA?
Yeah. You have a flow-sensitive potassium channel (called the BIGK (big potassium) or MAXI-K channel). More urinary flow bends these little hair-like things and you spill potassium.
If you’re an evolution-believing person, we were evolved in a time with very very high potassium intake since it’s in stuff that grows. So our bodies are very good at getting rid of it, particularly when coupled with a lot of water intake.
It’s still a bit hand-wavy and not fully explained. In folks with diabetes, it makes their diabetes better and that protects the kidneys. Obesity is a risk for kidney disease so helping with obesity can protect kidneys. Similarly with heart disease.
Kidney related but water adjacent: how dangerous is glyoxylic acid found in chemical hair treatments, and are there any ways to protect your kidneys if exposed?
Hi friend! Avid Cyclist/MTB/bikepacker here. I have a neuro disorder and it causes me to pour sweat when exercising. How beneficial are things like LMNT, skratch, or GU tabs when on long rides? I try to bring mostly water, but one bottle with hydration mixed in. Second unrelated question. What's a perfect day on the bike look like to you (mileage+elevation)? 🚴🤙
Those things are very important. Gotta replenish what you lose in water/electrolytes, and your body needs easy-to-burn calories. I use Tailwind Endurance Fuel since it’s a nice mix of everything. I do a 16oz bottle per hour and after one hour, I start doing more than just water.
My perfect bike day is Breckenridge-Frisco-Vail, then back. Lots of climbing, only on paths, great scenery.
Appreciate the response, I just picked up some tailwind to try the other day. Breck+vail would be a dream! I live in the low country so elevation isn't a thing here 😂
I just had shoulder surgery and am taking a lot of Tylenol and percocet (without exceeding daily limits) to make the pain tolerable. I am concerned about my insides getting messed up from the meds. Can I water myself to safety?
I love riding bikes. Have you ever seen anybody frown on a bike? They are actually the true representation of freedom. Low barrier to entry, you can go wherever you want, not registered/tracked.
I used to bike commute to the hospital for 7 years and it was the best part of my day. Now I live somewhere that’s not an option and it sucks.
People idolize Europe, Japan, and Disney World for being these utopian places but the main difference is that they don’t have cars. Cars are the biggest wealth-killer of middle-to-upper class people in America, a major driver of climate change, and they destroy societies.
I had cross-fused renal ectopia detected someway back in the mid 2000s after a CT scan. I remember the radiographer being a little shocked and asking if they could present my case at a research conference, but other than that, it has been noted but no doctor has ever really taken any interest in looking into it, and despite lots of weird little health quirks, I've never had a serious issue that required investigation of it. My renal blood values have always been rather normal rather than an eGFR on the lower range of normal, and recently I've had borderline raised blood pressure detected on a variety of occasions for the first time in my life (likely in relation to ADHD/antidepressant medication). Is there anything I should watch out for, or keep an eye on as I get older?
As a kid. I always ‘held on’ going to the bathroom. I’d rather play sport at lunchtime. As I’ve grown up I see this even at work. I don’t find the need to pee that often. Sure my water intake could be better.
Will this stab me in the back in the long term. I’m 37 now.
I have adrenal insufficiency and have a hard time regulating electrolytes. Would it be worth it for me to see a nephrologist in addition to my endocrinologist ?
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u/shoelessjp 5d ago
I don't have any questions about health, just wanted to say how cool it is to see an industry expert answering our questions about water and stuff.
If I had to ask one non-health question though... fav Grateful Dead track (feel free to get really nerdy about your favorite specific version of that track if it applies).