Water, bottled versus tap, any benefit to drinking alkalinized or bottled water? Health benefit of drinking, how many glasses a day is necessary? by Ray Sahelian, M.D.
November 20 2016


Water is a tasteless, odorless substance in its pure form that is essential to all known forms of life. There are companies that sell alkaline, ionized, or other forms. Are these scams or do they provide benefits?


Are you drinking more water than you really need? We have all heard the recommendations that we should all drink 8 glasses of water a day. However these recommendations have been made without adequate supporting data. There is plenty of water in many of the foods we ingest (vegetables, fruits as examples). Many people also get a lot of fluid by consuming large amounts of tea, coffee, juice, sodas, and other fluids. I know friends who always leave the house with a bottle of water even if they are going out for a couple of hours. I see them constantly sipping from the bottle as if they are going to get dehydrated if they do not have continuous fluid intake. Some people appear to be quite obsessed about this. There is no reason to be. It is thought that this push to drink more water may partly be instigated by water bottling companies who are making enormous profits at the expense of the consumer and the environment (so many trashed plastic bottles everywhere).


How much should you drink a day?
Depending on one's diet, climate and body size, it seems appropriate to drink on average 2 to 6 glasses of water or similar fluids such as tea or coffee a day. Drink at least a glass of water as soon as you wake up to stimulate bowel function and relieve constipation. Those who have an enlarged prostate may wish to reduce the amount of water or fluid they drink before going to bed.
There are claims that all people should drink 8 glasses of water a day but there are no studies that indicate that the human body requires this much water daily unless a person lives in a hot and dry climate or does a lot of indoor or outdoor physical activity. Some people claim that drinking lots of water improves skin tone, clears toxins, and helps suppress appetite. Although this may be slightly true, it is not as definitive and significant as some claim. Some individuals drink lots of water before or during meals to suppress appetite, but water is quickly absorbed from the intestinal tract and would not stay around like fiber-rich foods to cause satiation. Drinking a reasonable amount of water, such as 4 glasses a day rather than 8 is enough to flush out toxins. As to skin, drinking lots of water does not necessarily increase the water content of the skin. Journal of the American Society of Nephrology, online April 2, 2008.

Water intoxication symptoms
Water intoxication occurs when a person has consumed so much water that the salt levels in the blood become diluted,. When sodium [salt] concentrations are low in the blood, it actually allows water to leak out of the blood into the other tissues, a condition known as hyponatremia. The brain appears to be the organ most affected by hyponatremia, and begins to swell as water leaks out of blood and into brain cells. Usually, the symptoms are mild, such as confusion, headache and nausea. But if left untreated, people might wind up suffering seizures,


For weight loss, obesity, losing pounds, eating less
Obesity (Silver Spring). 2015. Efficacy of water preloading before main meals as a strategy for weight loss in primary care patients with obesity: RCT. A two-group randomized controlled trial was conducted in Birmingham, England. Eighty-four adults with obesity were recruited from general practices. All participants were given a face-to-face weight management consultation at baseline (30 min) and a follow-up telephone consultation at 2 weeks (10 min). At baseline, participants were randomized to either drinking 500 ml of water 30 min before their main meals or an attention control group where participants were asked to imagine their stomach was full before meals. The primary outcome was weight change at 12-week follow-up. Several measures of adherence were also used, including 24 h total urine collections. 41 participants were randomized to the intervention group and 43 to the comparator group. The water preloading group lost -1.3 kg more than comparators at follow up. There is preliminary evidence that water preloading before main meals leads to a moderate weight loss at follow up


Alkaline water
Question: I recently became aware of Alkalized / ionized water as it is one of the products I sell wholesale (I work for a Santa Monica, CA based grocery warehouse). A rep for REAL water (alkaline / ionized) impressively demonstrated that its ph is around 8 and she tested the ph of many other well known bottles. Those other waters were all somewhat acidic. The theory is that cancer (and perhaps other diseases) are prone to grow in an acidic environment but not an in alkaline one. Frankly I want to believe that there are healthful effects to be had from the consumption of alkalized / ionized water, etc. but I wanted to temper my enthusiasm for alkaline by hearing from some cogent medical experts about this. I came upon a particular MD online, a Benjamin D. Levine, M.D. Director, Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Dallas; it just seemed to me that he would know something about the subject so I sent him an email. Turns out he didn't know much on the subject at all, however he forwarded this to Tamara Hew-Butler DPM Phd, who sent me the following: "The movement of fluid between the intracellular and extracellular space is primarily dictated by effective osmolality with the effect of  pH and ionization negligible factors in total body water distribution. I have answered your queries below and welcome any further scientific documentation supporting the physiological benefits of ionized water to which I am unaware."

Beverage pH has minimal impact on the pH of the body and is not a factor in the movement of water between the extra and intra cellular space. The concept that ingesting a more alkaline beverage would enhance the intracellular movement of water seems physiologically implausible: as the amount of fluid ingested in proportion to the amount of total body water is generally not enough to influence the pH of the system, chemical buffers within the body can respond to alterations in pH in milliseconds and the total concentration of hydrogen (H+) ions in the blood is 40 nmol/L while the concentration sodium (the main effective solute in the body) is 140 mmol/L (~3.5 x 106 the concentration of H+) thus negating any effect of beverage pH on overall tonicity.


Water moves freely between intracellular and extracellular compartments in response to osmotic pressure gradients created by effective solutes (Na+, K+, and mannitol) that are impermeable to the cell membrane If we measure a serum sodium concentration below 130 mmol/L, the amount of total body water in the extracellular and intracellular compartments is in equilibrium; however, the concentration of sodium is below the normal reference range because 1) total body water is in excess to total exchangeable sodium (dilutional hyponatremia) or 2) excessive sodium losses (depletional hyponatremia) have occurred. The use of “ionized” water will have little impact on body fluid distribution for reasons detailed above.


References 1) Verbalis JG. Disorders of body water homeostasis. Best Practice and research Clinical Endocrinology and Metabolism 2003;17(4):471-503. 2) Suslow TV. Oxidation-Reduction Potential (ORP) for Water Disinfection Monitoring, Control and Documentation. University of California Division of Agriculture and Natural Resources 2004; 8149:1-5. 3) Vorobjeva NV. Selective stimulation of the growth of anaerobic microflora in the human intestinal tract by electrolyzed reducing water. Medical Hypothesis 2005;64:543-46. 4) Shoenut JP, Duerksen D, Yaffe CS. Impact of ingested liquids on 24-hour ambulatory pH tests. Dig Dis Sci 1998;43(4):834-9.


So, Dr. Sahelian, after hearing this Dr's opinion that suggests it will do little good to improve ones health etc, what do you have to say?


Answer: I have not studied this topic in great detail but I am skeptical of the claims regarding alkalinized water. In order to know for certain a large number of people would have to be placed on one type of water for at least a decade and compared to another large number of people who drink exclusively another form of water. I am not aware of such studies at this time and hence any claims by sellers of such water products are just speculation and are not based on actual human studies. As far as I know, most centenarians or those who have lived to 110 years or longer have never mentioned paying particular attention to the type of water they drank throughout their lives. I prefer to drink filtered water most of the time and suggest my patients to not be obsessed too much about these issues. There are too many other dietary and lifestyle factors that influence health and it is more practical to focus on these since they are more likely to make a major difference in overall longevity. There is a good article that I think makes a lot of sense, see http://www.chem1.com/CQ/ionbunk.html

Chlorinated and cancer risk
Drinking, bathing or swimming in chlorinated water may increase the risk of bladder cancer. Dr. Cristina M. Villanueva of the Municipal Institute of Medical Research in Barcelona says chlorine can be harmful when inhaled or absorbed through the skin, as well as when ingested. Chemicals, most commonly chlorine, used to disinfect water can produce by-products that have been tied to increased cancer risk. The most prevalent chlorination by-products, chemicals called trihalomethanes (THM), can be absorbed into the body through the skin or by inhalation. To investigate lifetime THM exposure and bladder cancer risk, the researchers matched 1,219 men and women with bladder cancer to 1,271 control individuals who did not have the disease, surveying them about their exposure to chlorinated water via drinking water, swimming pools, showering and bathing. The researchers also analyzed the average water trihalomethanes levels in the 123 municipalities included in the study. People living in households with an average household water trihalomethanes level of more than 49 micrograms per liter had double the bladder cancer risk of those living in households where water THM concentration was below 8 micrograms per liter, the researchers found. THM levels of about 50 micrograms per liter are common in industrialized societies. Study participants who drank chlorinated water were at 35% greater risk of bladder cancer than those who didn't, while use of swimming pools boosted bladder cancer risk by 57%. And those who took longer showers or baths and lived in municipalities with higher trihalomethanes levels were also at increased cancer risk. When trihalomethanes are absorbed through the skin or lungs, it may have a more powerful carcinogenic effect because it does not undergo detoxification via the liver. American Journal of Epidemiology, January 2007.


Bottled water benefit and risk, is it worth the cost?
Bottled water makers make millions off people who believe their products are purer than tap water, but consumers do not realize that they are less regulated than plain old tap water.


Dasani, a Coca-Cola product is simply purified tap water that’s had minerals added back in. For example, if your Dasani water was bottled at the Coca-Cola Bottling Company in Philadelphia, you’re drinking Philly tap water. But it’s not the only brand of water that relies on city pipes to provide its product. About 25 percent of all bottled water is taken from municipal water sources, including Pepsi’s Aquafina.


Tap Contaminated with Trichloroethylene

The most widespread industrial contaminant in drinking water — a solvent used in adhesives, paint and spot removers — can cause cancer in people. The National Academy of Sciences says that a lot more is known about the cancer risks and other health hazards from exposure to trichloroethylene than there was five years ago when the Environmental Protection Agency took steps to regulate it more strictly. Trichloroethylene, which is also widely used to remove grease from metal parts in airplanes and to clean fuel lines at missile sites, is known to cause cancer in some laboratory animals. EPA was blocked from elevating its assessment of the chemical's risks in people by the Defense Department, Energy Department and NASA, all of which have sites polluted with it. Trichloroethylene is a colorless liquid that evaporates at room temperatures and has a somewhat sweet odor and taste. It is one of the most common pollutants found in the air, soil and water at U.S. military bases. Until the mid-1970s, it also was used as a surgical anesthetic. Trichloroethylene also has been found at about 60 percent of the nation's worst contaminated sites in the Superfund cleanup program, the academy said. That's a step that could lead to stricter regulations. EPA currently requires limiting trichloroethylene to no more than 5 parts per billion parts of drinking water. A stricter regulation could, in turn, force the government to require more thorough cleanups at military and other sites. In 2001, EPA issued a draft document saying the risks of trichloroethylene causing cancer in humans were higher than previously thought. But that pronouncement was dropped after other federal agencies accused EPA of inflating the risks.


Trace amounts of metals such as copper and lead can be present in tap water and, depending on their levels, could be harmful. The risks of lead are well-documented - if you live in a house built before 1930, you should check that any old lead plumbing has been replaced with copper. Could copper itself cause problems. Trace copper ions present in drinking water can stop amyloid beta protein from being cleared from the brain (Alzheimer's disease is characterized by a built-up of this protein).

There is no scientific evidence to support that drinking "super oxygenated" water enhances athletic performance. So-called super oxygenated water -- water in which the oxygen content is increased significantly -- are marketed by various companies as a way to improve athletic performance by feeding extra oxygen to the muscles through the blood stream. Researchers from the Medical University of Vienna compared the performance effects of the maximum oxygenated water they could find (180 mg of oxygen per liter) with that of non-treated water from the same source. Twenty young men were submitted to intense bicycling exercises after having drank either 1.5 liters a day of oxygenated water or the same amount of untreated water, during two weeks. Consumption of super oxygenated water had no significant influence on maximum physical performance and maximum oxygen consumption. International Journal of Sports Medicine, March 2006.


Health Claim Notification for Fluoridated Water and Reduced Risk of Dental Caries
Under the Federal Food, Drug, and Cosmetic Act, a manufacturer may submit to the Food and Drug Administration (FDA) a notification of a health claim based on an authoritative statement from an appropriate scientific body of the United States Government or the National Academy of Sciences (NAS) or any of its subdivisions. On June 16, 2006, the FDA received a notification (the June 16 notification) from the law firm of Covington and Burling regarding a health claim for the relationship between fluoridated water and a reduced risk of dental caries. The 120-day period from the date of submission of the June 16 notification was October 14, 2006. Therefore, after October 14, 2006, manufacturers may use the claim specified in the notification, as modified by the notifier in a letter to FDA dated October 13, on the label and in labeling of any food product that meets the eligibility criteria described below, unless or until FDA or a court acts to prohibit the claim. The following three statements are considered authoritative for purposes of this notification.

Recommendation for Using Fluoride to Prevent and Control Dental Caries in the U.S. (Centers for Disease Control, 2001):
"Widespread use of fluoride has been a major factor in the decline in the prevalence and severity of dental caries (i.e., tooth decay) in the United States and other economically developed countries. When used appropriately, fluoride is both safe and effective in preventing and controlling dental caries. All U.S. residents are likely exposed to some degree of fluoride, which is available from multiple sources." (Summary section, page 1)
"Continue and extend fluoridation of community drinking water: Community water fluoridation is a safe, effective, and inexpensive way to prevent dental caries. This modality benefits persons in all age groups and of all SES, ...." (Recommendation section, page 24)
Oral Health in America: A Report of the Surgeon General (2000):

"Community water fluoridation is safe and effective in preventing dental caries in both children and adults. Water fluoridation benefits all residents served by community water supplies regardless of their social or economic status. Professional and individual measures, including the use of fluoride mouth rinses, gels, dentifrices, and dietary supplements and the application of dental sealants, are additional means of preventing dental caries." (Executive summary)
Review of Fluoride: Benefits and Risks (Public Health Service, 1991):

"Extensive studies over the past 50 years have established that individuals whose drinking water is fluoridated show a reduction in dental caries. Although the comparative degree of measurable benefit has been reduced recently as other fluoride sources have become available in non-fluoride areas, the benefits of water fluoridation are still clearly evident." (Conclusions section, page 87)


It is worthwhile to use a water purifier at home, this way you can save a lot of money by avoiding buying expensive bottled water.


Bladder problem in men
Drinking extra water is unlikely to relieve older men's bothersome bladder symptoms. Lower urinary tract symptoms, such as bladder pain and difficulty urinating, are a common problem among older men. In some cases, underlying medical conditions like enlargement of the prostate gland are to blame, but problems in the urinary tract can also cause the symptoms. With age, for instance, the muscles that surround the bladder can start to weaken and hinder the organ's normal functioning. Dutch researchers studied 141 men between the ages of 55 and 75 who were suffering lower urinary tract symptoms. They randomly assigned the men to either drink an extra 1.5 quarts of water each day or take a daily dose of an inactive "placebo" syrup. After six months, there were some changes in the water group's bladder functioning. However, the men had no clear improvement in their symptoms compared with the placebo group. Though study participants in the water group were instructed to add 1.5 quarts to their daily water intake, in practice they managed to drink only about 12 ounces more per day than the placebo group. That raised their urine production by about 10 percent over the comparison group. Urology, November 2006.

Bottled water brands
PepsiCo Inc. sells Aquafina bottled water which is made with tap water. PepsiCo, starting in 2007, will include the words "Public Water Source" on Aquafina labels. Pepsi's Aquafina and Coca-Cola Co's Dasani are both made from purified water sourced from public reservoirs, as opposed to Danone's Evian or Nestle's Poland Spring, so-called "spring waters," shipped from specific locations the companies say have notably clean water.
   Bottled water is being promoted all over the world by a number of companies such as PepsiCo, The Coca-Cola Co., Nestle, Cadbury Schweppes, Evian and S. Pellegrino. The environmental damage from the transport of this water all over the country and the world is enormous.



Q. I was going to suggest vitamin water to your subscribers for a great tasting & healthy beverage, but then I took a closer look at the ingredients and how it's sweetened. Apparently it is sweetened with crystalline fructose. So I looked it up online and found out that crystalline fructose, is derived from methanol, which raised a red flag immediately. I just purchased some for my first time yesterday. I am drinking it as I type. Actually, I decided to stop drinking it after I found out it contains crystalline fructose. And actually, I now have a funny taste on my tongue.
   A. We don't see any reason to drink water where fructose or crystalline fructose is added although small amounts are probably not harmful.


Q. I wish to seek your expert opinion on the issue of Alkaline Water . We live in Singapore and the water from the tap here is safe for drinking even without boiling. However, we learnt from some friends about the benefits of drinking ionized water, i.e. alkaline water. There are conflicting opinions on the websites on this issue and we are rather confused. We have been drinking alkaline water for the past five years but somehow do not seem to enjoy the benefits that we were told (by the supplier) that others enjoy from it – e.g. healing them of some health ailments like high blood pressure, etc. In fact, my hubby discovered that he has mild hypertension about mid last year. His reading averages from 130 to 155 (systolic), and 87 to 97 (diastolic). He’s aged 50 and not on any medication currently as we are trying some herbal remedies like Hawthorn, Kyolic and Tablets (combination of Potassium, Magnesium and Calcium). What is your opinion with Alkaline water? There seems to be some scientific explanation ( by Dr Weil ) on the website that this is not of any benefit to the body. We hope to hear from you because we can trust in your opinion.
   A. I am not aware of any research that says alkaline water is preferable to drink than any other kind of water. My preference is to drink regular, clean water, no matter what it's source. Those who do not trust their local water supply from the kitchen faucet could get a good water purifier.


Q. I saw an ad for mineral water with calcium and they claimed that high calcium mineral water is a good source of calcium. Does the calcium in this mineral water get absorbed well?
   A. High-calcium mineral water can provide useful quantities of bioavailable calcium.


Q. I would like to know if drinking distilled water is good or bad for health.
   A. Drinking distilled water is fine, but occasionally drinking regular or spring water would also be a good idea.


Q/ I was wondering if the use of water alkalinizing drops (suck as AlkaLife which is made of distilled water, potassium hydroxide & sodium hydroxide) can have any undesirable secondary effects on the body or health. Are there any risks for toxicity?
   A. We have not seen research regarding the use of AlkaLife so we don't know, it most likely appears to be safe unless high amounts are used. If you are concerned about any possible risks with AlkaLife, perhaps you can use very small amounts.


Q. I'm a BIG fan of your website and receive your newsletter. Your site has lots of helpful info about many different health concerns and supplements. I was wondering if you have anything on water safety and bottles? The reason I ask is because I'm employed at a health food store. We sell polycarbonate bottles for people to use. They are glass-like, non porous with no leaching of materials, etc. But, recently, there have been news reports about how, suddenly, polycarbonate bottles may be detrimental to one's health where they could affect hormones, etc. Does your site have any info about this and does Dr. Sahelian have an objective opinion about water safety and bottles? It's frustrating because it seems things are found out that is bad about everything! Any feedback would be appreciated-love your site.
   A. If one reads about all the possible chemicals we are exposed to, there seems to be a risk from almost everything. However, we have to put things in perspective and not to worry too much about risks that are very minor. The worry itself could be more harmful. As to these polycarbonate water bottles, I have not kept us with it to any great detail, but it is possible that tiny amounts of unhealthy chemicals may be leached, but I have not studied this in any great detail. But, on the scale of potential other harms and exposures we are bombarded with on a daily basis, I would consider this to be on the low end of worrying items. If a person is very concerned, they could use glass bottles, but then again there is a small risk of the bottle dropping and breaking with a possible laceration. Nothing is totally risk free.


Q. What bottled water do you recommend? Which do you think is the safest and the purest? I currently drink Sam's Choice. It says is uses reverse osmosis or distillation and it adds minerals, potassium bicarbonate and potassium chloride. Are these safe minerals to add and drink 4 or 5 bottles a day?
   A. I don't have any specific bottled water recommendations. I think it is cheaper and more environmentally proper to use a water filter attached to your kitchen faucet. Plus, the major brands use tap water for their water source, anyway. PepsiCo Inc. sells Aquafina bottled water which is filtered tap water. Coca-Cola sells Dasani which is also filtered water from public reservoirs.


Q. What happens with the salt in the blood when too much water is drank?
   A. The condition is called hyponatremia and can be dangerous. 


Q. I've had sleeping problems since I increased my water intake to 1 gallon per day. I am 24 years, male, currently bodybuilding, so I require a bit more than average water. The sleep problem is, ever since I upped my water intake (about a few months ago), I've started to wake up several times a night to go to the bathroom. I tried stopping (or at least slowing) water intake at about 3 hours before sleep. But, I just seem to wake up every 2-3 hours still. And I seem to be almost wide awake at those times, not groggy like I used to be when waking up in the middle of the night. It might be because my body is used to waking up at those times. Even when I don't really need to go to the bathroom, I still wake up several times. And ever since I've had this problem, I've noticed my testosterone levels are decreased dramatically, probably because of the interrupted sleep.
   A. There is no need to drink a gallon of water a day, There is no research that says drinking more than 8 glasses of water a day offers additional health benefits. Reducing water intake should reduce nighttime awakening. Also, many people take supplements that could cause sleep problems at night. It may be a good idea to stop all supplements for a few days.


Thank you for your informative newsletter. I was concerned in the case of your response to the question of how much water is enough water to drink daily, in your April 2008 issue. The gentleman in question asked if 8 glasses of water per day were adequate, and you stated that 4 would be enough. In view of today's society where people drink outsized amounts of caffeinated drinks which are well known and documented to dehydrate the body... in view of the fact that many of the off-the-shelf foods contain more sodium in one serving than we could possibly need, let alone after the many servings of food eaten in a day... in view of the fact that an enormous amount of the population eat a constant array of fried takeaway, more sugar than a small country would consume and certainly much less fruit and vegetables than is healthy, let alone good fibre vital for maintaing stable bowel health... it seems to me that 4 glasses of clear, clean liquid a day, (depending on the glass size) will most certainly not be enough for something as large as a human body. After resurrecting my health with Natural Therapies post massive and long term mis-diagnosed Chronic Fatigue Syndrome, I am the first to say, that if I had not drunk from 1 to 2 litres a day throughout recovery, and still to this day, I would not have been able to get my health back. Overdrinking water isn't neccessary. However I believe that even such common problems as headache, constipation and so on, often dissapear by drinking the right amount of clean, clear fluids, preferably filtered water; the same effect is not created by juices, even home juiced, or soups and certainly not this modern society's addiction to the rubbish on shop shelves that people drink by the bucket load. In much of Europe, as a very small example, people often still drink a short black coffee and a large glass of water to balance it. The hydration/ dehydration balancing act. This precaution is not often approached in much of Western Society where outsized amounts of fizzy drinks, coffee and such, are drunk one after the other all day long in repetitive monotony. Obviously people's bodies are telling them they are THIRSTY, but if you were to ask most people they would actually truly believe they were addressing their bodies thirst. How much are most bodies screaming out for clean fresh water? According to my Naturopath, most people's bodies are in such deficit it's almost the first thing she has to educate before even beginning with therapy.
    Different people have different opinions on the topic of idea water intake. If you have a study that disproves my point that 4 to 6 glasses of water are adequate for most health, normal activity people, I would be glad to review it.