Water is labeled acidic or alkaline based on a measurement system called pH. (7 being neutral, below 7 acidic, and above 7 alkaline). The pH of the water alone is not a determinant of its health benefits or harm. Our saliva and stomach acid adjust the pH of orally taken food items and water, while our kidneys and our breathing process of exchanging O2/CO2 maintain blood pH. The human body maintains a constant pH equilibrium not dependent on the pH of the water consumed.
Why is tap water acidic?
Tap water is usually acidic due to rainwater being the main source. Rainwater is slightly acidic due to carbon dioxide and pollutant gases like oxides of sulfur and nitrogen reacting with water to form corresponding acids. The presence of microbes/germs releasing carbon dioxide contributes significantly to acidity. Drinking such acidic water presents some important health hazards. Firstly, if the water in our pipes is acidic, gradual corrosion of the pipes can happen over a period of time exposing us to long term accumulation of heavy metals which is certainly undesirable. Secondly, water containing microbes can be a source of many waterborne infections some of them serious.
Erosion and sedimentation of rocks also add to the acidity of tap water but also are a source of salts like sodium, calcium, potassium, magnesium and other trace minerals useful for the body.
Effect of RO filters on water
The RO (reverse osmosis) filters remove all salts, metals, and germs (including bacteria and viruses) from tap water making it safe for drinking. It is true that the pH of RO filter water is 5.5-6 which is mildly acidic (pH of the stomach is between 2-3). However, that acidity is due to more relative CO2 (carbon dioxide forms carbonic acid in water) in RO filtered water. The RO filter does not stop CO2 from filtering through but blocks out the other mentioned components thereby relatively increasing CO2 content. Therefore, RO water is like having mildly carbonated water, very unlike the highly carbonated and high sugar soft drinks. RO filtered water also helps to cut down unwanted sodium intake from water. Many brands of distilled packaged water also have pH in a similar range as RO water. So RO water even though mildly acidic, represents one of the safest and purest forms of drinking water.
Does Alkaline water offer health benefits?
Alkaline water available as packaged brands in the markets has a pH between 8-9. They contain salts of sodium, potassium, calcium, and magnesium (mineral salts) which are vital for body functioning. The word ‘ionized’ is sometimes added to alkaline water to denote the presence of these minerals salts. During workouts, athletics and sports, these mineral salts are lost at a higher rate. So it may benefit people frequently involved in such activities to carry alkaline water as an immediate replenishment of these salts and to improve exercise performance. However, care should be taken that these don’t contain added sugar for taste, and should not increase daily sodium intake beyond the recommended levels. For most people eating a balanced diet consisting of vegetables, fruits, grains, legumes, and yogurts, will provide adequate amounts of all these salts needed by the body.
Makers and advocators of Alkaline water claim several health benefits for alkaline water which are currently inadequately substantiated and speculative at best. Apart from the mineral salts in alkaline water, there is no conclusive clinical evidence that the alkalinity itself contributes to any health benefit. However, no harms of drinking Alkaline water have been brought out either except that people with impaired kidney function should be cautious and consult their physician before changing over to Alkaline water consumption. There are some isolated opinions that people with acidity problems may experience some relief due to the neutralizing property of alkaline water, but again no medical recommendation can be made at this stage without conclusive clinical evidence. Today household Alkaline filters – UV filters as well as RO filters with decreased ORP (Oxygen Reduction Potential) are available which make the water alkaline after purification, however, this claim needs to be validated by the possession of an authorized Certificate of Product Registration (CPR).
The bottom line is that the pH or the acidity/alkalinity of the water alone does not have any significant health impact. The important thing is that your water intake should be adequate (at least 1.5 to 2 liters/day). The drinking water should be tolerable in taste (which is compromised in both high acidity or alkalinity), be devoid of toxins, heavy metals and disease-causing germs, and be stored in clean containers.
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