Doctor's Note

I’ve previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the eight-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That’s the impetus behind this concept of evidence-based medicine (what a concept!). Ironically, though, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalinizing machines? See Alkaline Water: a Scam?

It’s so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

To post comments or questions into our discussion board, first log into Disqus with your NutritionFacts.org account or with one of the accepted social media logins. Click on Login to choose a login method. Click here for help.

  • Plantstrongdoc M.D.

    I will go and get a cup of water – right now!

    • Joevegan

      I brew my first cup of white tea before opening NF each weekday morning. Bummer, I’m out of lemons.

    • Julot Julott

      Only if you are thirsty though…

      • Jan Hunsinger

        NO Julot…if you are thirsty you are WAY past the dehydration point!

        • rob

          What if you are rarely very thirst? Go for me so I pee less at night. Ok, I am 81

        • Lawrence

          I disagree. We have a natural thirst indicator and we should learn to listen to it. How much water you need depends upon who you are, what you eat, where you live and what you do. I barely drink any water but I do drink about one cup of tea a day. I eat a whole plant food based diet and use non-animal based milk for my breakfast and smoothie for lunch. I find if I drink water on top of that I just have to pee all the time. Overworking your kidneys is not a good idea.

          • My mum has dodgy kidneys, and her kidney specialist has her drinking 4L of plain water a day. He is very happy with her progress, and thinks she will avoid having to go on dialysis.

        • Julot Julott

          No way lol, it just means your body could use some water like on a car the gas tak is not empty when the warning light comes on, the body is not that poorly designed. ;D

          • lounge

            As long as you’re urine is clear or very light light yellow, you’re properly hydrated.

        • Wade Patton

          I think this is only accurate if one is engaged in high-intensity behavior, like cycling or other sport. To think that a bit of thirst indicates “way past” dehydration for the less active person doesn’t make sense, otherwise what point would thirst serve?

          • Brandjontan Jon Tan

            I would think, “bit of thirst” body signal is a warning indicator for “starting point of dehydration”. (1) And if I ignore this, my mouth would begin to feel dry, lips may start to become “chapped”, or even throat starts to become irritated (like prior to a “sore throat”). A feeling of (what we Chinese call) “body-heatiness”. (2) I will then increase the amount of water consumption…to help cool down the “body-heatiness”. It works.

        • Chris

          So shall we apply the same principle to feelings of hunger?

  • brucegray

    re bladder cancer, it’s possible people with troublesome bladders (frequency, urgency, pain with urination) are disinclined to drink adequate water. chicken and egg thing, yet again.

    In my view, as a clinical physiotherapist, poor hydration also contributes significantly to accelerating joint wear and tear, muscle/tendon/ligament pathologies (tendinosis, calcific tendonitis), bone spurs (plantar fasciitis), etc

    I would also think it very likely that the brain’s glymphatic system (CSF role in brain waste clearance) is heavily dependent on hydration levels and unimpeded CSF flow in and around the cranial vault and into the spinal canal. So hydration may play a very important role in delaying the build up of beta-amyloid and all dementias.

    In fact, it may play a pivotal role in clearing the body of cancerous cells and infection. If we don’t have adequate fluid on board to get white blood cells to where they are needed, in adequate numbers, then infection and tumors are less likely to be halted.

    • Stewart

      Bruce, your assertions seem totally reasonable and, I think, are likely correct. I would be delighted to see any studies that back up what you are saying but if they don’t exist they are at least very reasonable inferences.

      I developed type one diabetes for my 21st birthday (that was the approximate date I first noticed the polyuria and polydipsia) and for the next 6 months I just figured if I was thirsty I needed the water. Consequently, I did not become as severely dehydrated as many undiagnosed diabetics do. So it seemed to me that the water might have saved my life by flushing some of the excess ketones as well as limiting dehydration. (Oh, in case anyone else does’t know, the build up of ketones along with dehydration is the basis for going into a diabetic coma which often ends in death. Hence my own inference that a ketogenic diet such as Atkins and some paleo fads is bats**t crazy. But I digress.)

      In any case I am taking your assertions to be valuable.

      • Lawrence

        Hi Stewart, Sorry to hear you have Type 1 Diabetes. I hope you have seen “Simply Raw: Reversing Diabetes in 30 Days”. While most of the benefits are for Type 2 suffers there are also benefits for Type 1 provided you can still produce some of your own insulin. I suggest it is worth a look.

    • David Johnson

      >>it’s possible people with troublesome bladders (frequency, urgency, pain with urination) are disinclined to drink adequate water

      I know that’s the case for me. In fact for those with nocturia, one standard recommendation is to stop drinking fluids 3 (or perhaps even 4, I forget) hours before bedtime, i.e. partially dehydrate oneself. I used to do this, and in fact would partially dehydrate myself before social outings, etc. Result: I got gout (twice in 4 years), which my doctor thinks occurred because I was dehydrated.

      Unfortunately for people in my category, it looks like a choice between sleeping through the night (or getting up only once) and partial dehydration. I’ve picked the former…

    • Kim Churchman

      I think there’s an unmentioned reason that bladder cancer is the 4th leading cause of cancers in men: Smoking. The #2 smoking-related cancer is bladder cancer. So it makes sense to me that increased water throughput helps move more tobacco-derived irritants and toxins out. Bladder cancer: Thar’s tar thar!

  • Wade Patton

    I’ve long utilized the color of urine and frequency of urination to determine my fluid intake adequacy. Yes it is “after the fact” but it’s completely relevant to my personal physiology and activity level. At some point in the past I tried drinking 8 full _glasses_ and found it completely ridiculous. Thanks for clearing up the source of the ancient, incorrect water “requirements”.

    Also, when working out (cycling-high energy, sometimes for hours on end) I consume 16 to 32oz per hour-depending on temperature and intensity. Anything less drastically reduces urinary flow.

    • The studies still aren’t clear enough for me to make a recommendation that patients should drink “X” amount of water a day. There are many variables involved as Dr. Greger mentions. For folks consuming a whole food plant based diet they “eat” alot more water (e.g. vegetables, fruits, soups) a day than those eating a standard american diet. I believe you should consume regular fluids during the day. If your urine is clear you are most likely adequately hydrated so I think using the color of urination is a reasonable way to go as you suggest. Thirst often lags behind dehydration… hence the saying in cycling… “drink before you are thirsty and eat before you are hungry”. Each patient should adjust their intake to what works for them. Of course there are always exceptions so if you have questions or symptoms you should consult with a knowledgeable health care professional.

      • Wade Patton

        Yes, I tried “fruitarian” a few years ago, then went cycling per normal. I tried to drink the same amount of water as before. The result was stopping 6 times in one 3-hour ride! (crazy too much) That’s when I realized how much water the fruit was delivering. Experience has taught me the perils of under-hydration. No study necessary. Drink up–but in moderation!

        • Julot Julott

          Especially hyponatremia always happens when there is over-hydratation because the big sodium loss especially on a low sodium diet, there is usually no hyponatremia without over-hydratation even on a very low sodium diet, sorry for my english~

          • Wade Patton

            Yes, there have been some publicized hyponatremia deaths in the US where folks had no idea that too much water could be harmful and drank WATER and died. They drank a lot. Probably in a contest or challenge. Read up folks before “contesting” with your body.

    • Dom Suda

      I agree about color of urine and hydration

    • Dom Suda

      I agree about color of urine and hydration

  • justme1

    I take a glass of water with every trip to the kitchen .. and since I’m always in the fridge I do believe I get plenty of water … lol

    • Matthew Smith

      Great rule of thumb. Drink a glass of water each time you are on your way to the kitchen. I think drinking a lot of water can help people eat less and get some of the benefits of a calorie restricted diet. At least I’m hoping that’s what drinking a lot of water would do. In me too!

  • telguera

    There is no mention here that recommended water intake has any relation to the weight of the body. I drink one glass of water every day for every 10 pounds of body weight.

    • Debra

      Really? So I would need 14 glasses, if I weighed 140 pounds?! There is no way that can be necessary. I’ll try to get 6.

      • aribadabar

        Agree – you have to be in a sweltering heat doing high-intensity activity to require that much water…which in itself is not very healthy.

    • Joseph Gonzales R.D.

      Great point. Clinical nutrition guidelines vary, but they do account for weight, sex, and activity level. If you want to see the equations used let me know there are many.

  • OK, but what about the water source? With God knows what ending up in our water supply, is bottled water any better? Do they do anything to bottled water to remove all the potentially bad stuff?

    • Joseph Gonzales R.D.

      Great questions. Dr. Greger covers this in his video comparing bottled water to tap water. See if that helps? Other links you may want to check out are listed in the “Doctor’s Note” below this video. The “Alkaline Water: a Scam?” video is a interesting. Thanks, Ty.

    • Unfortunately it seems water sources and processing for bottled water is all over the map – some is just tap water, some is from springs, etc. If all you have added to water is chlorine then I believe just leaving it on the counter or in the fridge for a few hours will allow it to come out.

      • Joevegan

        Most water is processed with chloramines which I used to age for a month when I had tropical fish. Supposedly, chloramines take longer to evaporate out than chlorine.

      • Mike Quinoa

        Yeah, when we had cats they would turn up their noses at freshly-drawn tap water. After it had been sitting for a few hours they were willing to partake. I’m sure their sense of smell was far superior to mine.

    • Kim Churchman

      Bottled water is tap water, bro. Municipal water supply. It may say ‘sourced from an artesian spring’ or similar, but the entire city is sourced from the same, so all they do is turn on the tap, maybe with more filtering. They may say ‘No fluoride!’ but that means no artificially added fluoride. There are varying amounts, from not enough to too much, of naturally-occurring fluoride all over the world, and it’s the same atom in the same little handful of molecule variations. So maybe buy a filtration pitcher if you want, but stop the river of empty bottles going from all of us to the landfills. Thanks for reading this far. Fluoride is an ATOM.

      • Brux

        Yes, fluoride is an atom, but really it is an “ion”, that is – it is very reactive and always attached to something else. When it is in the ground that is usually a homogeneous mineral, from a natural geological formation, a salt that can be dissolved in water, along with the something else. When it has been added to your water the same used to be true, however ( and I don’t know this from personal experience ), but what I hear is that most fluoride now comes from industrial waste, meaning you do not know what is with it, or where it comes from, or what impurities are in it.

        • Kim Churchman

          thanks Brux, can you cite a substantiating reference for the ‘industrial waste’ statement from a respectable source please? I know many ‘industrial wastes’ are good reusable materials. One I can think of is corrugated cardboard, another pre-consumer paper recycling. I’m sure not all industrial waste is as obnoxious as smokestack tar.

          • Brux

            > I’m sure not all industrial waste is as obnoxious as smokestack tar.

            I did not say it was. What I said was that compared to those who get fluoride in their water from natural mineral sources, the fluoride we get in our water is not the same. The fluoride atoms may be the same, but where it comes from and what goes with it is not tested, approved or certified.

            The problem is that fluoride is being “virtually” prescribed to most of us like a medicine, but there is not prescription, there is no choice, there is no dosage or control. If this was a medicine the FDA would not allow it.

            If you are interested I think you can do your own searches … it is easy. But to get you started, here’s just one a many: http://fluoridealert.org/issues/water/fluoridation-chemicals/

          • Kim Churchman

            I was hoping for information from a disinterested source…?

          • Brux

            Anyone willing to write about something is going to be an interested source. What I do is to look for things I know are facts, and look for things I know are lies, and then weight them.

  • Normand

    I have read in many books about the benefit or drinking a glass of water

    with real lemon juice as soon as you get up in the morning.

    Are there any scientific benefits to this?

    Just very curious.

    Thank you.

    • Joseph Gonzales R.D.

      Hey Normand. I have also heard this, but never thought to look into the research…until NOW! ;-) I didn’t find anything substantial. I feel like there is no harm to this and many folks drink more water with lemon. I love lemon water! I did find this study suggesting just the smell of citrus may boost mood so perhaps that is enough reason to drink lemon water? If anyone else finds any studies please post!

      Thanks for your comment,
      Joseph

    • lilyroza

      Adding lemon to your water increases you
      logo

      The Truth About 11 Allergy Myths You’ve Probably Always Believed
      Are you really allergic to penicillin? Will your pet make you sneeze and wheeze? Is black mold really serious? Doctors clear up our most pervasive misunderstandings about allergies and our health.

      By Kelsey Kloss
      81
      SHARES
              
      9 of 12
      The Myth: “I’ve always been allergic to penicillin.”
      Even if you experienced a bad medication reaction as a child, people typically outgrow a penicillin allergy. “I would say 80 to 90 percent of people who think they’re allergic to penicillin are probably not,” says David Rosenstreich, MD, director of the division of allergy and immunology at Montefiore Medical Center. Penicillin is a common treatment for a bacterial sore throat, sinus infections, skin infections, or syphilis. Allergic reactions may include skin rashes, asthma attacks, or swelling of the eyes, lips, face, or tongue. “If you need a penicillin-related drug because of your specific infection, ask for a test to see if you’re really allergic or not,” says Dr. Rosenstreich.

      9 of 12

      Category: Everyday Wellness
      81
      SHARES

      Want to stay smart and healthy?
      Get our weekly Health Reads newsletter
      Email address Sign Up
      how we use your e-mail
      by TaboolaSponsored LinksFROM THE WEB
      10 Tasty Taco Recipes
      Kraft Recipes
      5 Things That Golf Pros Do That Amateurs Don’t
      Square to Square Method
      What Does Your Last Name Say About You
      Ancestry
      Top 10 Cheap All-Inclusive Resorts
      TripCurator
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      15 Funny Church Signs That Are Going to Hell
      11 Hilarious Restaurant Sign Fails
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      15 Funny Church Signs That Are Going to Hell
      11 Hilarious Restaurant Sign Fails
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      10 Short Jokes Anyone Can Remember
      How to Spot a Liar: 7 Clues Anyone Can Use
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      15 Funny Church Signs That Are Going to Hell
      11 Hilarious Restaurant Sign Fails
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      10 Short Jokes Anyone Can Remember
      How to Spot a Liar: 7 Clues Anyone Can Use
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      15 Funny Church Signs That Are Going to Hell
      11 Hilarious Restaurant Sign Fails
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      10 Short Jokes Anyone Can Remember
      How to Spot a Liar: 7 Clues Anyone Can Use
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      10 Short Jokes Anyone Can Remember
      How to Spot a Liar: 7 Clues Anyone Can Use
      by Taboola
      More from RD.com
      8 Hilariously Bad Cake Decorating Decisions
      Doctors Confess: 11 Most Annoying Things You Do
      8 Signs of Disease That Are Written All Over Your Face
      10 Short Jokes Anyone Can Remember
      How to Spot a Liar: 7 Clues Anyone Can Use
      by Taboola

      Dr. Greger recommends adding a squeeze of lemon to 4 cups of hybiscus tea a day, as a way to keep your antioxidants high between meals.

  • ChrisC

    While we’re on the topic of water, please do a segment on the healthiest water – filtered, tap, mineral, bottled? Also, what are the major contaminants that should be removed from water? (e.g. cadmium) Any recommendations as to which filters do a good job of this? Thanks!

    • Joseph Gonzales R.D.

      Great suggestion! Dr. Greger may have read your mind. Please see my comment to Ty Ford two comments below. Perhaps water contaminates could be tested through our NutritionFacts Research Fund if we receive enough interest? I am unfamiliar with the best water filter or any hard science on the matter. If you find any (or others can weigh-in) please post here!

      • Gemini2010

        See Chris Beat Cancer and also Natural News Mike Adams who both highly recommend the Berkey Water Filtration system.

        • chorisia

          I have used a gravity berkeley filter with doulton filters for more than a decade,rainwater into a pond,ramshorn snails thriving in the pond so am I :-)

    • Billy

      When my city announce that they were going to begin adding fluoride to the water, that inspired me to find a filtration system to counter their action. I chose a reverse osmosis system that fits under the sink for my home. It removes about 90% of fluoride along with chloride, particulates and many other minerals, although some of the minerals it removes may be helpful and I have to get them from food instead. It cost about $250 but has lasted 8 years so far, although I have to pay an additional $50 a year for replacement filters.

      • Joanna Carroll

        What is this system? It it a whole house system or just for drinking water? I am using a Big Berkey.

    • robert

      In evaluating the quality of water with respect to health you need to think about what you want in it and what you want to exclude. There is also the cost vs degree of purity issue. Chlorine and its highly toxic breakdown products can be eliminated by carbon filters and eliminating conventional tank type water heaters and replacing with on demand water heaters. Priority wise showers are actually a greater exposure risk than drinking water. Search IMPACT OF WATER HEATERSON THE FORMATION OF DISINFECTION BYPRODUCTS. A high quality carbon matrix filter can be a good solution for drinking water if your city meets standards. Another drinking water treatment is reverse osmosis filtering which in conjunction with carbon filters removes both chlorine and minerals. This is a more pure water, but many consider it deficient in taste and minerals. You can add minerals back through various products which are essentially sea water without the sodiium. I get my water from a well and in this case you need to test the water and get professional advice about how to treat it. For example my water source is too high in iron and extremely hard. The well water is treated with ozone which oxidizes the iron so it can be filtered by an iron filter. Then the water goes through a softener and then to a reverse osmosis system for drinking.

      • Brux

        The latest technology, chloramine, a mixture of chlorine and ammonia is almost impossible to get rid of, and in any case very expensive to get rid of.

    • Gary

      After reading the Consumer Reports article in Feb 2012 on water filters I bought the number 2 rated “Best Buy” Clear2 O CWS100A quick connect to a faucet model for the whopping price of $15. I use about 3 filters a yr for $30.
      I fill a 1 gal jug every 2 or 3 days with it. If you buy one, order the longer hose for hooking to a faucet. Or get a hose at an auto parts store…lol

      Out of 18 fllters tested it was rated just under the Reverse Osmosis Kinetico K5 system that cost a whopping $1,800…..

    • Stu

      I posted part of this in another section previously so forgive me for those that notice…

      I’ve found spring water in my region to be the closest match to the parameters outlined below.

      “not only does completely demineralised water (distillate) have unsatisfactory organoleptic properities, but it also has a definite adverse influence on the animal and human organism.”

      After evaluating the available health, organoleptic, and other information, the team recommended that demineralised water contain:

      1.) a minimum level for dissolved salts (100 mg/L), bicarbonate ion (30 mg/L), and calcium (30 mg/L);
      2.) an optimum level for total dissolved salts (250-500 mg/L for chloride-sulfate water and 250-500 mg/L for bicarbonate water);
      3.) a maximum level for alkalinity (6.5 meq/l), sodium (200 mg/L), boron (0.5 mg/L), and bromine (0.01 mg/L).

      The lowest morbidity was associated with water having calcium levels of 30-90 mg/L, magnesium levels of 17-35 mg/L, and TDS of about 400 mg/L (for bicarbonate containing waters). The author concluded that such water could be considered as physiologically optimum.

      http://www.who.int/water_sanitation_health/dwq/nutrientschap12.pdf

  • Brux

    My problem with drinking lots of water is that I am peeing like 2 times an hour if I drink a lot of water. It is not convenient to be doing something, then have to get up and go pee, and then come back and have to go pee again very soon. I find that I can hold my pee if I wait for it to get almost painful and then at some point it stops, but I doubt that is good for me. I have no idea is any of that is normal or healthy? I don’t usually get thirsty, but my understanding is that the sense of thirst goes away the older you get.

    Why don’t they do tests based on how often it makes people pee, or what the color of their urine is when they pee? It seems odd that no one really knows how much to drink. I can see it now, someone will invent some kind of sensor and develop an app to tell you when to drink. ;-)

    • valnaples

      Brux, and for ME, it helps me get up and move around at work! I like to drink lots of water & green tea during my work day so that I can go downstairs to the rest room (taking the stairs of course, more exercise!) pretty much once each hour…I try to do this not only for the health benefits of staying hydrated but also for the benefit of getting up and moving around as much as possible each work day!

    • Lawrence

      Hi Brux, I think that how much water you need depends upon who you are, what you do, where you live and what you eat. Too many variables to make a one size fits all suggestion. The colour of urine is unreliable indicator. I eat a whole plant based diet and so my urine is always coloured because of the nutrients etc. If I am thirsty I would rather eat some fruit than drink some water as it is more nutritious. There is a danger of drinking too much water from brain swelling to overworking your kidneys. So, I think some common sense goes a long way.

  • Han

    I’ve got this funny idea that I get a common cold if I don’t drink enough water. The idea being that if I’m thirsty my mucous membrane in my nose and throat dries out and I am more subsceptible to contracting the virus.

  • Neil De Silva

    Most water is Polluted with Toxins such as Chlorine, Lead, Fluoride. I replace water as much as possible, with King Coca (King Coconut water) whenever I can!!

    • jim.henry

      Or you can get a Berkey water filter …

    • Mike Quinoa

      I bought a ZeroWater pitcher-style filtration unit, which comes with its own TDS (total dissolved solids) meter. And sure enough, with a fresh filter you somewhat amazingly get a reading of .000 TDS. My question is, am I also filtering out beneficial substances, such as minerals, etc.?

      • Joanna Carroll

        I don’t know about the ZeroWater pitcher, but the Berkey Filter system removes just about everything, however it claims to keep the good minerals in.

      • Joseph Gonzales R.D.

        Hey Mike. I am not familiar with any of these filters, sorry. I know Dr. Greger has more videos on water coming very soon! Stay tuned…

    • Allan

      I see many speaking of water but only a couple speak of the quality of the water. Quality is key! Ph and ORP are critical for absorption and utilization for the body. Chemicals in the drinking water are also very bad. Our governments allow to many chemicals in our city tap water. But Bottled water can be even worse! I suggest point of entry filtering and ionizers at your kitchen sink for drinking and cooking.

  • guest

    What about the temperature of the water one drinks? In the US everybody drinks cold water directly from the fridge, regardless of the season. Ayurvedic advice is to drink water close to the body temperature.

    • Joseph Gonzales R.D.

      Right. I have heard of this, too. The idea I think is that cold water puts more “stress” on the body, but I have not seen any research to support this.

  • jim.henry

    In 1980, at age 28, I herniated two discs (L4-L5 and L5-S1) in a basketball injury. From 1980-2011, I suffered from acute back spasms about a half dozen times a year, which I would manage with chiropractics and anti-inflammatories. Sometimes the pain would be with me for a week or two weeks at at time. So I got used to counting on being significantly compromised in my ability to sit, exercise, move about, etc. for about 15% of my life. Then in 2011 I was in Washington, D.C. and had a spasm. A friend took me to his chiropractor, Philip Bahnson, who had me lie face down on his table. He put his finger directly on the epicenter of my pain and asked me if that was where it hurt.

    When I affirmed that it was, he said, “That’s on your kidney meridian. Are you drinking 6-8 cups of water a day?”

    “Nope.”

    “And avoiding the dehydration of caffeinated drinks?”

    “Nope.”

    “Why don’t you try that?”

    And thus my life changed dramatically. I start every day with two big glasses of water and make a point to drink more at intervals. I cut out coffee. And I have been to the chiropractor only two or three times in four years! I have to go to the bathroom more often, but it is a small price to pay for being pain free. I am also a kidney stone former, about once a decade, and I am hoping the extra water will help be in that category, too, as per Dr. Greger’s other posts.

    Drink water!

    • Joseph Gonzales R.D.

      Great story, thanks for sharing!

  • Robert Haile

    I live on the equator and drink over 1 gallon per day, mostly water but also tea and coffee. I even get dehydrated surfing and drink about 3.5 pints before I surf or play tennis. I drink a pint while playing tennis and another after I ride my bike home.

  • Sandra

    Please use the phrase “reduce your risk” when talking about cancer, not the word “prevent”. I exercise, eat healthy foods, have the right weight for my height, meditate, and I’m battling metastatic breast cancer. I certainly don’t regret my healthy life style, but it’s no guarantee that you won’t get cancer.

    • DanielFaster

      Prostate cancer in my case, not metastasized. 4 years plant based and 15 yrs of bike racing would not undo 50 years of Western eating . . .

    • SeedyCharacter

      Sandra, Thanks for pointing out that we are all vulnerable to cancer in spite of any and all healthy behaviors.

      If you don’t know about Dr. Jeanne Wallace’s integrative/nutritional cancer practice (available via phone consultation), do check her out: http://www.nutritional-solutions.net She is brilliant, evidence-based and her patients have had excellent results.

      Best of luck to you in your healing journey.

  • David Hochstettler

    I don’t drink water. I eat my water. I eat about 5 to six pounds of food a day. Most of it is over 90% water. I love water but since I went on a plant based diet if I drink water I am up every 2 hours going to the bathroom unloading 16 ounces of urine

  • Dommy

    How many ounces is “a cup”?

    • Wade Patton

      A measuring cup is 8 fluid ounces. A traditional US coffee cup is 6 fluid ounces, but many consume coffee from mugs that hold upwards of 20 oz.

      That is why “10 cups” on the coffee carafe only fills 2 or three “cups” for the Javahounds. For water, we’re talking 8 or a half-pint.

    • fred

      Put this program on your desktop and CONVERT away….

      https://joshmadison.com/convert-for-windows/

  • vegank

    I’m terrible at keeping up with my fluids, I consume more caffeinated beverages than water.
    Hopefully the plant based diet is compensating for that but I ‘ll try what is recommended here.
    Thank you for reminding us Dr Greger & team.

  • David Hochstettler

    There is 8 ounces in a cup. For many adults a full bladder holds 16 ounces

  • Marco Bellacci

    Hello friendly people.
    I have been told that it is a good idea to squeeze som fresh lemon in the water before i drink it. What do you think about that?

    • Wade Patton

      Is there some benefit that is associated with this “good idea” that “you’ve been told”?

      If it helps you stay hydrated when you wouldn’t otherwise, then go for it. But be wary of any “non-whole” food. Juice is one.

      • Dommy

        Fresh lemon juice added to green and white teas increases its antioxidant and polyphenol absorption.

      • Marco Bellacci

        Hey Wade and Dommy.

        I can see in your messages that I must be bether at asking the questions
        :).
        Dommy> that must be the answer. I gues if that is how it Works in tea then it may be the same in Water. Do you have any interesting material on the subject?
        Thank you :).

  • I drink a gallon of liquid a day between straight water and the water in my vegetable and fruit juices. This is one of the reasons why I am never tired during the day.

  • saipan

    There are two choices. Drink a lot and pee a lot. Or not drink very much, die early and not pee at all.

  • Neale Blackwood

    Hats off to the guy in 1921 with a sample size of one – he did a pretty good job.

  • AA

    Off topic, but does anyone have an opinion on this new study on the Paleo diet vs the heart health diet?

    Paleolithic nutrition improves plasma lipid concentrations of hypercholesterolemic adults to a greater extent than traditional heart-healthy dietary recommendations

    Robert L. Pastore,

    Judith T. Brooks,

    John W. Carbone

    For some reason I can’t post the link.

    • DanielFaster

      Extensive negative facts on paleo and other low carb diets are presented by Dr. Greger at atkinsexposed.org

    • Here is the link–thanks, I’ll add it to my paleo article stack.

      • nodelord

        WOW, does this mean I should run out to whole foods and grab some steak for dinner…. I’ve been WFPB for 2 yr LDL not loweri

      • Mike Quinoa

        Dr. Greger, you often hear that your urine should be “pale yellow,” for example. But are doctors referring to the color that appears in a specimen container, or to the color that appears in the toilet bowl, where it is, of course, diluted. Thanks.

  • Mike

    I think this thing of drinking “x” amount of water is
    completely absurd and was started by the bottling industries to make lots of
    money. I firmly believe that nature is wise so therefore you should drink water
    ONLY when your body asks for it and NOT like a medical prescription
    “x” cups every “y” time. Think, for example, of the people
    who live in the desert. I can bet they DON’T drink 4 glasses of water a day
    simply because it’s very scarce, and they’re not sick people who are dying of
    cancers. Besides, these modern methods of getting bottled water rid of the
    “bad” elements and make it clean and sterile simply makes it a HIGHLY
    PROCESSED product which has been stripped of its useful nutrients for the body
    such as vitamin B12 and some minerals not to mention all those toxic substances
    used to “purify” it (which would be something like refined sugar).
    I’d say that almost all the food (unprocessed of course) we eat has water in it
    because it’s an essential component of life. So the advice here is: DRINK WATER
    WHEN YOU’RE THIRSTY AND NOTHING ELSE BUT WATER! :-)

    • dommy

      Elderly people however tend to lose their thirst signal. They are often dehydrated as a result.

      • Wade Patton

        But they don’t likely need 8 “glasses” of any liquid per day. Urine flow/quality is still a valid gauge in my book.

  • SeedyCharacter

    If you’re discouraged from drinking more because of a need to pee too frequently, be sure to assess how much caffeine you may be consuming in teas (black, green, white), coffees, energy drinks, etc. As I’ve aged my bladder has become highly sensitized to caffeine and it causes me to have “the urge” for hours after consumption. I love a morning cup of coffee or black tea but have to settle for de-caf now and even that has me running to the bathroom more than I want.

  • lisa

    I literally came here to see how much water I should drink a day… Thats what the heading of the article hinted at…. yet its not here. Thanks for a massive waster of time. I will stick to my 8 glasses for now as I am no wiser from reading this. Thanks for a load of babble with no substance.

  • Thank you for addressing this topic Dr. Greger. I have heard unreferenced water claims all my life from so many people. Finally someone is presenting some science..

  • David Johnson

    So I take it then from the comment near the end about other beverages not counting, that even decafe or herbal coffee and tea don’t count? I’d find it hard to drink so much water on top of tea and coffee so I hope this is not true.

  • dogulas

    Vitamin D. What’s better? Increasing risk for melanoma, or…

    John Mcdougall says vitamin D supplements are associated with increased risk of pancreatic cancer and prostate cancer, raise bad cholesterol, increase the occurrence of kidney stones, and other kidney and autoimmune problems https://www.youtube.com/watch?v=d2zCUyppVd0&t=2m5s

    As an extremely white person prone to sunburn, should I really be sun-tanning for 10-15 minutes a day, or should I just take enough vitmain D to keep my blood levels right around 30 ng/ml?

    • Wade Patton

      Here are a dozen or two Vitamin D and Vitamin Supplements and Vitamin requirements videos from Dr. Greger: http://nutritionfacts.org/?s=%22vitamin+d%22

      Enjoy!

      • dogulas

        Thanks, but I’ve seen them all. What I would like to hear someone weigh in on is whether it would be best to get the sun rather than taking the supplement. Considering the risks associated with each (for example, melanoma from sun exposure).

        • Wade Patton

          Ok, fair enough, personally speaking I know I get enough exposure for vitamin D health requirements and use brimmed hats, long-sleeves (oh the joy of fishing guide shirts) and sunscreens to limit further damage to my skin. Pushing 50 and my forearms and hands tell it-despite generally looking younger than most folks my age. I worry about the crap in sunscreens as much as the UV sometimes and is why I’ve gone to “cover” mode as much as practical (without being pasty).

    • guest

      Mcdougall says that vitamin D pills should not be taken. He flat out says this. No fortified vitamin D products, vegan fortified milks, vegan yogurts, you name. He says vitamin D supplements are harmful across the board. Do we actually think humans were meant to live indoors, hiding from the sun?

      • Brux

        McDougal’s opinion is just another opinion. Skin cancer is a fact of life. There is somewhere in between the two sides that makes sense. I see no one else raising the red flag against vitamin D, and a lot of people telling us to limit sun exposure. Why would you just decide to accept one person’s opinion like you are their disciple? I mean that is OK when you are following the son of God if they existed, but for any human talking about a science that we all know is not figured totally out yet, to me it doesn’t make a lot of sense.

        Brux

    • Gary

      Maybe our Vit D level is not that big of a deal as it’s cracked up to be to live a long healthy life as is shown by the 1940’s Okinawan diet.
      They had very low levels of just 2% of the Recommended Dietary Allowance. Scroll down to page 444

      http://okicent.org/docs/anyas_cr_diet_2007_1114_434s.pdf

      Given that, I don’t worry about burning my skin up or taking the large amount of pill supplements to get my level in the “recommended range.”

    • Joseph Gonzales R.D.

      Complex! Dr. Greger has more to come on this! Please stay tuned. I the meantime check out my comment, here, as I address this question. See if it helps? Thanks, Douglas!

  • tJprescott

    How does water consumption affect out sodium and mineral balance? Is spring water with minerals better than distilled? Dr. Greger has posted little research on sodium and minerals. What are your opinions on this meta analysis that does not support lower levels of sodium intake for the general population?

    http://www.math.montana.edu/~jimrc/classes/stat524/notes/Midgley-1996-SaltMetaAnalysis.pdf

    • Joseph Gonzales R.D.

      You can dilute electrolytes in the body by drinking too much water, especially on hot days in people unaccustomed to the heat which can lead to dangerously low sodium levels. Still, this does not mean eating lots of sodium is helpful. There is a newer study
      that concludes sodium should still be < 1500mg for adults.

  • Michael

    This is great… So, to be clear- do cups of tea, milk or broth count towards the recommended amount of water we should be getting?

    • Joseph Gonzales R.D.

      Hey Michael. Yes, listen again at 3 minutes 45 seconds or view the transcripts where Dr. Greger says “Now but that’s water from all sources, not just beverages, and we get about a liter from food and the water our body actually makes, and so these translate into a recommendation for women to drink 4 to 7 cups of water a day and men, 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures. We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. Note, though, in the cancer and heart disease studies I mentioned, the benefits were only found with increased water consumption, not other beverages, so unless you have conditions like heart or kidney failure, women should drink 4 to 7 cups of water a day and men should drink 6 to 11.”

      • dorange

        How about all this water “flushing” minerals from the body, like potassium, for example? I remember once I had a diarrhea, and my doctor told me to keep myself well hydrated, and he specifically told me I had to take coconut water or homemade physiological serum (water with a pinch of salt and a pinch of sugar), because water alone wouldn’t be hydrating.

        • Joseph Gonzales R.D.

          Sure, you can dilute electrolytes in the body by drinking too much water, especially on hot days in people unaccustomed to the heat which can lead to dangerously low sodium levels.

  • RainbowCupcakes

    Fantastic! I can recommend this to my friends. :)

  • Sophia Keenesburg

    2 Liters or a bit more ….
    But water also is in other stuff you eat. Fresh veggies, fruits and so also contain water offcourse.
    We (netherlands) have GOOD drinkingwater right out of the tap … NO fluoride nor Chlorine (other process to clean the water no Chlorine needed) ….

  • Jeranthemum Beardikus Beckman

    Tap water? There are far too many dissolved solids in tap water not to mention chlorine and fluoride! Drink distilled or reverse osmosis water, distilled mimics the hydrologic cycle (rain water) and is the purest with lowest TDS (1-4PPM). leaches minerals? Pulls inorganic (calcified deposits, non-usable), organic minerals (those found in plants) are left unmolested.

  • Mery Daae

    I drink A LOT. Especially during summer. Up to 6-7 liters some days. Is that bad?

  • Saroya

    Tap water ~ that’s full of toxins ~ what kind of ignorant advice are U giving here ~ only drink purified water ~ tap water is carcenogenic

  • Christo Okulian

    Dear Doc and NF staffs,

    I have been drinking purified water that taken from water under the soil, the purifier contains carbon active,1 antibacteria based on chlorine and another carbon active as the last filter before we drink. i know that vit b12 produced by bacteria, if this purifier use chlorine as anti bacteria, it means there is potential a trace amount of b12 from the native bacteria in this water. is it possible that this water from that has been purified soil water contained vit b12 ?kindly comments. thx

  • Guest

    Here’s an interesting article by a doctor who’s study indicates that getting enough water isn’t really something we need to be concerned about:
    http://www.nytimes.com/2015/08/25/upshot/no-you-do-not-have-to-drink-8-glasses-of-water-a-day.html?smid=fb-nytimes&smtyp=cur&_r=0&abt=0002&abg=0

  • Rebecca

    I recently attended a lecture given by a neurologist about healthy aging and the mind. She said that she NEVER drinks water, only tea and multivitamin ECO drink (http://www.ecodrink.com/ecodrink-daily.html). Is there really any benefit to drinking ECO drink instead of tea and water? Is ECO drink worth the money? Thank you!

  • Modus Operandi

    I’m often thirsty throughout the day and drink a lot of water (6-7 liters day) and it still feels that it’s not enough. Sometimes my stomach is full of water but I’m still thirsty. I’ve always been very thirsty, since I’m little.

    Dr. Greger, do you think some people are just more sensitive to thirst, hunger and other bodily signals? It seems to be the case for me, like with sleep deprivation, for example.

  • Diana

    The quote you post at minute 1:15 is not from Hydration and health: a review but from “Author Response: Is Whole Body Hydration an Important Consideration in Dry Eye?”

  • Sarah Tabler

    Drinking enough water has never been an issue for me, I adore water! My mother has always labeled me as a “water baby” because, since I was able, I’ve been pounding down the water. The last several years, there have been rumors and information spreading concerning drinking TOO MUCH water which, to me, seemed improbable. But, it did get me wondering a bit in regards to consuming too many liquids throughout the day and the risk/potential to flush out vitamins and nutrients before they’ve been absorbed. Personally, I drink a minimum of 2 gallons of filtered water daily, this doesn’t include all the water I get from eating mostly raw fruits and veggies either. So, is there such thing as drinking too much water? If anyone has any insight on this, please respond!

  • Andrew Dorfman

    simple observations on a complex topic: how much water do we need?

    while searching the internet for “recommendations” on the amount of water to drink daily i found a number of natural and “paleo” sites recommending to hydrate based on thirst.

    it strikes me that “authoritarian” guidelines and recommendations, in the form of “rules”, suggesting water intake be based significantly on thirst might miss the fact of our very human tendency to habituate to all kinds of conditions, some of them potentially unhealthful.

    a person might rest in a chronically under or over hydrated status simply because it is a familiar adaptation. for example, if a person is used to running “dry” (or “wet”), then the thirst mechanism would not prompt a person to “correct” the present hydration status via drinking more, thereby moving toward an idealized status of “physiologically” optimal hydration, because the mechanism is suppressed and otherwise experienced as a “normal” level of hydration.

    personally,i eat a diet of uncooked fruits and vegetables with some seeds and nuts, and notice that i am hardly ever thirsty, and i also notice that my urine is almost always clear or near-clear. i generally feel fit and well and at age 58 i am sometimes told that people guessed me to be younger.

    i wonder if this kind of observation relative to clear urine can be tested as an approximation of optimal hydration. if the pee is near-clear, are we hydrated?

    what about a hydration estimate based on thirst + pee lightness? if these could be established to be reliable signs, then the rules become secondary. and if they can be reliable signs, then people could at least in theory, by taught to find the inner hydrometer themselves.

    is there anything obvious or dangerous that stands out in this simplification which i am not seeing?

  • Cezar Derevlean

    Is it recommended to drink water before, during or after a meal?

    I’m interested especially during the meal, because I’m doing it and seems like everywhere there are split opinions.

    Thank you!

  • TvP

    This seems to be good advice and something I’ve been following. However, I’ve been scanning the site and internet as a whole for information regarding water/liquid intake while eating and whether it aides or slows digestion. is there any actual scientific evidence one way or the other, it mostly seems to be anecdotal or hand waving? Thanks

  • berinho7

    what about those who have kidney failure ?

  • Pam Sobek

    Why the difference between men and women? If size is the issue, then small men and large women might need to adjust the recommended amounts of water.

  • Guest

    Do you recommend using a filtration system for tap water?

  • Chris

    I don’t drink water from a cup. I use a glass. What size glass should I use ? No idea! Also I drink water chilled from the fridge – is that good or bad?

    • Cody

      Hi Chris, I am a volunteer for NutritionFacts.org. Most glasses are more than 8 fl. oz., usually around 12 fl. oz., but obviously depending on the size of the glass. If you have a measuring cup, you can test out how many cups fill up the glass. Remember, one cup is equal to 8 fl. oz.

      Also, drinking chilled water is just fine. The main idea is to just drink plenty of water. I hope this helps!

  • Ian4health

    Does drinking water with your meal negatively impact digestion?

  • Ian4health

    Does having water with your meal negatively impact digestion?

    • docbeccy

      The pendulum has seemed to swing back and forth on this subject. For years people have been trying to choke down more and more water in the belief that we are all horribly dehydrated. Lately more research has come out saying that we should drink when we feel thirsty. It does seem that we often put off responding to our thirst so we may well be on the dehydrated side. Many diet plans recommend drinking a tall glass of water to decrease misplaced thirst as hunger prior to a meal as well as transiently take up some room in our stomachs. The Indian practice of Ayurveda has several rules about drinking water. One of them is to not drink a lot of water during or around your meals partly to avoid bloating as well as to avoid the dilution of digestive enzymes. Those are some theories. Like most things, you have to figure out what works best for you.

  • healthy ian

    Does having a cup of water with your meal negatively impact digestion?

    • Christine Kestner

      Hi, healthy ian. I am Christine, a NF Volunteer Nutrition Moderator. Although I have seen no credible research evidence to support this, there is a theoretical possibility that drinking water with meals could dilute the hydrochloric acid in the stomach, especially if a person has hypochlorhydria, or low stomach acid, to begin with. This is thought to be more likely with advancing age. Drinking water with meals will increase the feeling of fullness, and may contribute to gastroesophageal reflux simply by increasing the amount of “stuff” in the stomach, putting more pressure on the sphincter where the esophagus empties into the stomach. Eating foods that are very high in dietary fiber without enough water is not recommended. Other than that, if you are concerned, simply drink water between meals. I hope that helps!

  • Elias Durán

    How many times a day should we eat?

    • Thanks for your question Elias.

      That is a complex question that will really depend on a variety of factors but currently there is not enough evidence to state anything for certain.

      According to a review (see here):

      “Although major research efforts have focused on how specific components of foodstuffs affect health, relatively little is known about a more fundamental aspect of diet, the frequency and circadian timing of meals, and potential benefits of intermittent periods with no or very low energy intakes. The most common eating pattern in modern societies, three meals plus snacks every day, is abnormal from an evolutionary perspective. Emerging findings from studies of animal models and human subjects suggest that intermittent energy restriction periods of as little as 16 h can improve health indicators and counteract disease processes. The mechanisms involve a metabolic shift to fat metabolism and ketone production, and stimulation of adaptive cellular stress responses that prevent and repair molecular damage. As data on the optimal frequency and timing of meals crystalizes, it will be critical to develop strategies to incorporate those eating patterns into health care policy and practice, and the lifestyles of the population.”

      My practical suggestion is to eat when hungry and stop when full.

      Hope this answer helps.