| + | This annex has been intensively reviewed by many scientifically oriented individuals, including Dr. Lee Rozelle and Dr. Ronald L. Wathen. Dr. Rozelle summarized his review: The data for their conclusions, summarized in Annex 8 of the WHO unofficial guidelines, are not very convincing from a scientific viewpoint. The volume of water consumed per day was not indicated and the length of time of the experiment for the human "volunteers" was not indicated (one year fpr rats). The physiological changes reported apparently were based on rat and dog studies. For dogs, the same physiological changes were observed for water containing 50 mg/L and 1, 000 mg/L. 5 The conclusion of a minimum TDS of 100 mg/L is confusing and thus not very convincing. In the human studies, diuresis was observed particularly on the second day of the study (the increase in urine output reported to be 18%). The volume of water in the body from the "distillate" was reported to be 50 to 100% higher than the "other groups." The Russians also reported increased elimination of sodium, potassium, chloride, calcium, and magnesium in the urine, and the specific gravity was reduced. In the blood serum, the sodium was increased and the potassium decreased. Then it was reported that the "tendency" for similar changes were observed after consumption of 100 mg/L TDS and 1, 000 mg/L TDS. The water intake (based on thirst) of various TDS waters was not clearly reported. In some cases it was difficult to determine if the data were from animals or humans. In summary, the Russian studies, as reported in Annex 8 of the WHO document appeared not to be rigorously scientific. Dr. Wathen reviewed it from a medical point of view and wrote the following: The Annex VIII of the report is an alleged "review" of water and salt balance under the influence of a variety of water and salt intakes, in a variety of animals, including humans, exposed to a variety of conditions. The review is long on deductions, but very short on (re) presentation of solid data. Moreover, probably only a handful of references cited in this review (assuming they are cited correctly) may be from creditable scientific journals, that is, journals which demand proper scientific methodology and peer review of all work, prior to publication. Many of the cited articles may be from journals of "personal opinion": being versed only in English, it is impossible for me to establish the credibility of the cited work. This review cited observations on the organoleptic features of water (i.e., consumer appreciation of taste, odor, and color qualities) to underscore precise, physiologic thirst slaking with specific levels of TDS -- containing water in response to volume depletion. To begin with, the quoted electroencephalographic studies probably indicate only that a maximum number of receptor sites (taste buds) have to be recruited through stimulation to provide a maximum brain (alpha) wave response and that the TDS level in water providing the maximum response was between 200-600 mg/L of salt. One would expect such a response; one might also imagine that receptor response (sensitivity) is considerably tempered by prior salt and mineral exposure for the individual. Organoleptic features are very, very unlikely to define whether a given water source is healthful on non-healthful or that the amount imbibed is appropriate to need. Moreover, taste receptor electrical activity, being unlikely to reveal preference by the consumer, means the consumer must be asked whether he or she prefers a given type of water. More often than not, preference reflects prior experience (learned behavior). 6 The review refers to exposure to desert and exercise conditions for humans and how water lost in sweating should be replaced, not with purified water but with salt water. Who would disagree with this conclusion? With GatoradeR, for example, selling to extremely large U.S. and world markets, one hardly needs to be reminded in this day and age that volume and salt losses encumbered with the sweating of heavy exercise are best replaced with a fluid whose constituents are more aligned with extracellular fluid in the human. GatoradeR, though billed a being "low sodium" on its label, is in fact rather high in salt content (both sodium and potassium) and it provides a rapid, convenient, and safe way to promptly reconstitute vascular volume after heavy exercise. Dizziness, even syncope (passing out), from volume depletion are thereby avoided and strength of the individual is better sustained, due both to volume replacement and the glucose contained within Gatorade. GatoradeR is a water source to be taken only to replace severe fluid losses accompanying sweating; it generally averts the need for supplemental salt tablets. GatoradeR, in an opinion which may not be shared by the Gatorade Company (Chicago, IL), is not a source which should be used to replace normal fluid and electrolyte losses any more so than pure water should be used to accommodate severe volume losses. In the presence of salt accompanying usual dietary food intake (4-8 gm/day of sodium in U.S.), GatoradeR might conceivably lead to volume excess. A 64 oz. serving of GatoradeR contains: 880 mg of sodium; 200 mg of potassium; and about 400 calories, as carbohydrate (112 grams). There is no magical solution; one should drink what's appropriate to the circumstance. Replacement of the large fluid losses accompanying heavy exercise or thermal exposure, therefore, has nothing to do with using purified water for normal drinking and cooking purposes, the latter being paired with normal food intake to meet salt and mineral needs. In normal day-to-day activity not associated with extremes in sweatloss, the salt and minerals accompanying normal food intake more than meet daily dietary needs of such elements, whether consuming potable water (e.g., TDS of up to 500 mg/L) or purified water (e.g., TDS 100 mg/L) or pure water (e.g., 0.111 mg/L TDS). Salts and minerals are not "leached" from the human body; they are preferentially retained or excreted, either of these events occurring relative to whether or not one is surfeit in water or salt or both. In short, the human body is not a lead or copper pipe which "leaches" in the presence of purified water. The Annex VIII review is very misleading in this regard. I also think it is incredible to suggest that, in the absence of abnormal water loading experiments, consumption of demineralized water will cause distortion of the mucosal cells lining the GI tract. Besides, in the normal human setting, such water is often combined with other elements (e.g., coffee, tea, fruit juices, soft drinks, etc.) which raises its TDS prior to consumption. But, even if the TDS is not raised by some external means, through the additions of saliva, gastric secretions, and small intestine secretions beyond the stomach, 7 there is an internal elevation in TDS of any dilute fluid one might drink. It would be my opinion that the adsorptive portion of the GI tract, that is, the small intestine, in the absence of extreme water loading, never sees a hypotonic solution sufficient to cause the mucosal cells to swell or to appear damaged. There is a tendency in this review to draw conclusions from observations in anhidrotic (nonsweating) laboratory animals (dogs, rats, and rabbits) and apply them to the very hidrotic (sweating) human. That is, the review often draws conclusions from fluid, electrolyte, and acid-base studies in "non-sweaters" and seems to transfer these conclusions to the "sweaters." It is imprudent physiologically, if not scientifically erroneous, to do so. I found the reported physiological data to be very confusing, often at right-angles to prior knowledge. One wonders if the responses to various levels of salt in water were confused when citing data from the actual papers used in the review. I personally have never heard of osmorceptors being present in the gut which might serve to regulate fluid adsorption. And certainly, I have never heard of the liver being a repository of salt to be released to reconstitute salt levels in the vascular compartment. This statement, I think, is borderline preposterous. The literature cited here has been misconstrued or is comprised of essentially factitious observations. Salt in all body fluid compartments redistributes bidirectionally in attempts to off-set excesses or insufficiencies in extracellular fluid constituents, particularly in the vascular (blood volume) compartment. The following responses have been received from different experts in many different fields: WHO's Dr. Galal-Gorchev states that WHO has "no information that such (low TDS) water would have and adverse effect on mineral balance". U.S. EPA's Dr. Edward V. Ohanian, Chief of Human Risk Assessment Branch wrote, Drinking water supplies a number of minerals that are important to human health. However, drinking water is normally a minor source of these minerals. Typically, the diet is the major source of these beneficial minerals. I am not aware of any data adequate to support the conclusion that water with low levels of minerals is unsafe. The U.S. Navy has used distilled water with less than three ppm TDS aboard ship for more than 40 years. Surface ships while on shore take on water from shore sources, but it is common for submarines to provide nothing but purified water for months at a time, all with no reported ill effects. This was confirmed with separate sources at the David Taylor Research Center in Annapolis, the Naval Sea Systems Command, the Bureau of Medicine and Surgery, and the Navy Environmental Health Center. Finally, the Surgeon General directed the Navy to address the subject formally in 1972. The conclusion was that drinking distilled water is not harmful. The University of Illinois Health Sciences Library's ONLINE SERVICES department was contracted to search the MEDLINE database for the several key word groups back to 1980. That search produced 18 articles, but only two relevant ones, both supporting the proposition 8 that the physiologic mechanisms of homeostasis are more than adequate to permit routine drinking of purified water. Article 1 described experiments in which dogs were given large amounts of distilled water to lower the blood osmotic pressure while monitoring very closely the pH and C02 of arterial blood and the breathing rate. They found that the blood osmolality has a direct effect on breathing in addition to the known effects on kidney function. Thus, homeostasis appears to be controlled while intentionally consuming low TDS water. Article 2 described experiments with rats which had had their pituitary glands removed ("hypophysectomized rats)", and which therefore should show some damage to the hormonal control system. They found that the renin-angiotensin-aldosterone system worked well even without a pituitary, suggesting an additional control system leading to the maintenance of homeostasis. None of the 18 articles, including these two, showed any direct information about the subject matter of interest, but only that the homeostasis mechanism in living beings has significant abilities to adapt to different situations and inputs. 9 DISCUSSION OF FIELD EXPERIENCES There are no known scientific data which clearly demonstrate that the consumption of low TDS water by humans will or will not lead to harmful effects on the human body. However, a number of field experiences can be cited which support the premise that the consumption of such water by humans does not cause such harmful effects. There are no known documented experiences which show that consuming low TDS water will create any long-term health effects. The U.S. Navy has used distilled sea water for human consumption for approximately 40 years. TDS levels below 3 mg/L have been reported and consumption of this water for months at a time is common on submarines. No health problems have been reported by the Navy and they feel low TDS water is safe to drink. The U.S. Army uses reverse osmosis units to provide drinking water for soldiers in the field. They do not consider low TDS water to be a problem and have no minimum standard. The U.S. EPA conducted a project in San Ysidro, New Mexico in which the TDS was dropped from 800 mg/L to a range of 40 to 70 milligrams per liter. No health effects were observed during the one year test. Possibly the largest field study of human consumption of low TDS water is within the United States where municipal systems are delivering water in this category. Millions of people currently consume such water, and this practice has gone on for decades. Exact data are difficult to obtain due to seasonal changes, use of blended water from multiple sources, and changes of sources. However, the following levels have been reported: Boston, MA Portland, OR Baltimore, MD Lake Tahoe, CA San Francisco, CA Seattle, WA Denver, CO New York City, NY 64 mg/L 23 mg/L 89 mg/L 50-64 mg/L 27-154 mg/L 34-47 mg/L 39-216 mg/L 41-283 mg/L In addition to these areas, thousands of private wells, as well as numerous small municipal systems in the U.S., produce low TDS water. No known health effects or problems have been reported as a result of this widespread practice. Thousands of TDS reduction devices have been sold residentially in the United States for decades. No reports of mineral depletion or health effects are known as a result of the consumption of this water. In Plains, Texas, where the drinking water was brackish at 1500-2000 mg/L TDS, a change was made to desalinated water and the residents experienced temporary diarrhea. Because of the high initial TDS and because of blending, the treated water exceeded 100 mg/L TDS, which is above the definition of low TDS water established for this report. 10 In Montreal, a study compared the gastrointestinal disorders of two groups; one consumed tap water, while the other consumed reverse osmosis water. The group consuming the tap water had a higher incidence of GI infections. While neither of these experiences can be considered conclusive, no evidence of mineral leaching, the topic of this report, was reported in either case. NASA has reported no ill effects from the consumption of approximately .05 mg/L TDS water on board space craft. It appears that the possibility that this could have been a problem was never seriously considered by NASA. In a field test in Boulder, Colorado with about 50 families, an experimental, zero discharge water system provided drinking water containing about. OS ppm TDS. No ill health effects were caused as a result of drinking this water. In conclusion, the field experiences cited suggest that there are no long-term ill health effects, specifically the mineral leaching from human tissue, due to the consumption of low TDS water. 11 CONCLUSION It has been concluded that the consumption of low TDS water, naturally occurring or received from a treatment process, does not result in harmful effects to the human body. This is based upon the following points: • No public health organization with authority over the drinking water quality anywhere in the world has enacted or even proposed a minimum requirement for total dissolved minerals in drinking water. The human body's own control mechanism (homeostasis) regulates the mineral content of the body fluids and the discharge of different types of ions from the body of normal health individuals drinking water with low or high mineral content. Several types of scientific literature searches have found no harmful effects to the human body attributable to the consumption of low TDS water. Review of the Soviet report has shown that the scientific methods used are questionable and the conclusions are either vague or unsupported by the data. • Many examples of real-world situations in which large populations have been and continue to be provided exclusively with low TDS water without any reported unusual or ill health effects, establishes the safety of consuming such waters by human beings. |