Water is the key to life, sustaining every cell, organ and metabolic function within in the body. While the benefits of drinking water are commonly understood, less well known are the pros and cons of different types of drinking water and their varying effects on our overall health.
While the ideal water is a subject of debate and controversy, this article simply aims to review some of the health effect of the wide range of water products currently available to us.
For the majority of the world’s population, tap water comes from sources on the Earth’s surface such as dams, reservoirs, lakes, rivers, catchments and even the ocean (post-desalination).
However up to10 million cubic kilometers of water, including more than 90% of the world’s freshwater,lays underground in subterranean aquifers (layers of porous and permeable rock such as limestone and sandstone, accessed via wells and boreholes), providing up to 40% of the world’s drinking water.
Groundwater may be ‘harder’ than surface water, meaning it contains higher levels of dissolved mineral ions, absorbed from rocks and soil. Hard wateris not known to have adverse health effectsand mayhelp consumersachieve recommended daily intake of nutrients, such as calcium and magnesium, which are essential for good health.
Depending on geographic location, groundwater can also be muchhigher in natural fluoridethan surface water.
While 5.7% of the world’s population drink deliberately fluoridated water to tackle tooth decay, ingesting high concentrations can result in dental and skeletal fluorosis among other potential health problems.
The greatest health concern from drinking surface water is its high susceptibility to contamination from bacteria, parasites, viruses, chemicals, pharmaceuticals and stormwater runoff containing sediments and pollutants.
Therefore, before it’s piped to households, surface water is treated, filtered and disinfected with chlorine, chloramine or ozone to eliminate or reduce these substances to acceptable levels.
Groundwater is often cleaner than surface water and potentially safer to drink with little-to-no chemical treatment, due to aquifers acting as natural purifiers, trapping sediment and pathogenic bacteria.
Groundwater may still receive treatment due to contamination from leaking sewage pipes, septic and storage tanks; pesticides; chemical fertilizers; hazardous natural substances, such as arsenic; and landfill seepage.
Despite measures to ensure the best quality drinking water, low levels of contaminants and pathogens may remain and on occasion there have been seriousoutbreaks of waterborne illness. Though chlorinating water is typically effective in destroying pathogens, it’s ineffective against Cryptosporidiosis and Giardia Lamblia parasites, which can cause gastroenteritis and pose serious risks to people with weakened immune systems.
Tap water can also contain low levels of potentially carcinogenic byproducts, includingtrihalomethanes, created by disinfecting municipal water supplies, as well as chemicals leached from corroded plumbing, such as lead, cadmium and copper, which in high quantities can interfere with children’s physical and mental development and cause increased blood pressure and kidney and liver problems in adults.
Unless an alert or ‘boil water advisory’ has been issued, tap water is usually safe to drink, with no imminent risk of adverse health impacts. Still, millions of households worldwide attempt to remove these remaining contaminants with the use of water filter water, which can cost $20 to several hundred dollars.Image: Idea Go / freedigitalphotos.net
Bottled water is a major industry, costing more than 100 billion dollars globally, with popularity growing even in countries with some of the cleanest tap water.
Bottled water is favoredfor its improved taste and purported health benefits over tap water, even though manyare unsureas to why it’s meant to be healthier. While it can help people stay hydrated while they’re on the move, bottled water is generally no healthier than tap water nor is it always free fromchemical contamination,waterborne disease, orfluoridationand can even potentiallyleach unwanted chemicals, such as antimony and bisphenol-Afrom the bottle.
Some bottled water has been found to be just tap water filtered to remove impurities, but can cost several dollars compared to tap water, which generally costs a fraction of a cent per liter. Other than price, a major advantage of tap water is that it’s rigorously checked for contamination and potential health hazards on a daily basis to ensure quality, while bottled water is generally tested less regularly and stringently.
Tens of millions of people worldwide access their own private source of groundwater by tapping underground aquifers via wells (e.g. over 15 million householdsdo so in the USA alone). Private wells are not regulated or checked by governments and therefore provide users with potentially all the water they need while entirely offsetting water bills.
Well owners can also avoid chemical disinfectants used in public water supplies, which some sayimproveswell water’s taste.
Unless wells are constantly maintained and regularly checked for contaminants by owners, drinkers may be at risk of Hepatitis A, giardia, campylobacter, e. coli, shigella, cryptosporidium and salmonella as well as toxins and pollutants such as arsenic, gasoline, nitrate, phenol and selenium.
Wells are a considerable investment, costing thousands of dollars to install plus additional expense for electricity to power the extraction pump and possible water treatment.
Though we already rely on rainfall to recharge dams, reservoirs and aquifers from which we source drinking water, millions of people in dozens of countries collect rainwater for drinking (e.g. more than two million people in Australia use rainwater as a major source of drinking water).
Well designed harvesting systems with clean catchments and storage tanks can provide a free, renewable source of water, clear of impurities and devoid of controversial additives in tap water, such as fluoride and chlorine.
Rainwater is considered ‘soft’, so it lacks many of the beneficial nutrients found in tap water, such as magnesium, calcium and iron. Rainwater can become easily contaminated due to improperly constructed and managed harvesting systems or through atmospheric and land pollution dirt, animal feces as well as dissolved metals (e.g. lead and zinc) leached from materials in the water catchment system and storage tanks.
Though pathogen levels in rainwater are generally lower than surface water, there have been reported outbreaks of Legionnaire’s Disease, campylobacter and botulism as a result of drinking rain water.
Rainwater tanks can be a fairly expensive option to obtain water, costing hundreds or several thousand dollars.
Hot & Cold Water
A common rumor suggests that drinking cold water, especially after a meal, can cause cancer or heart problems, though this is largely false. For many people, cold water is more refreshing, hydrating, soothing and better tasting than warm or room-temperature water.
As well as eliminating parasites and bacteria in our tap water, boiling water can remove small concentrations of residual chlorine from drinking water (which despite being considered safe by most health organisations, many people fear can increase risk of serious ailments), as well as reduce concentrations of detrimental disinfectant byproducts.
Sparkling / Carbonated Water
Due to water’s often bland flavor, many people turn to a fizzier alternative to increase the enjoyment of drinking a long, cool, glass of H2O.
A common rumor is that sparkling water can leach calcium from the bones and increase calcium excretion through urination. Though a connection has beenfound to exist between calcium loss and caffeinated carbonated drinks, sparkling water doesn’t seem to have the same detrimental effect on bones.
Opinion is a little divided on whether sparkling water can exacerbate tooth decay.One study found that it had a negligible effect on dental erosion, especially compared to juices and cola which are 100 times more damaging.
Carbonated water may create discomfort for those with irritable bowel syndrome, by increasing bloating and gas. Some bubbly drinks also have a high sodium content, making it a potential risk for those who have to monitor their salt intake due to various conditions such as high blood pressure, fluid retention and poor bone health.
One study found that sodium-rich carbonated mineral water may actually help reduce the risk of cardiovascular disease in postmenopausal women. Further research has shown that sparkling water may improve indigestion, constipation and gallbladder emptying.
Spring & Mineral Water
Springs are formed when groundwater emerges naturally from an aquifer to the earth’s surface. Some spring water is said to originate from an ‘Artesian Well’ which is an aquifer confined between slabs of impermeable rock in which natural pressure allows water to rise above the aquifer or all the way to the surface without the use of a pump.
Mineral water is also naturally produced at springs and contains at least 250 parts per million total dissolved solids, including minerals and electrolytes such as calcium, magnesium, potassium, sulfur, silicon, sodium, bicarbonate and iron.
The health benefits of spring and mineral water depends on the quality of the aquifer and how protected the spring is. Minerals from a well managed spring can benefit bone structure, energy production, nervous system function, blood clotting, muscle activity,kidney stones,teeth, skin and hair, liver purification, digestion,blood pressureas well as many other functions.
Drinking directly from a poorly managed spring may be hazardous to health, as it can easily become contaminated from various pollutants and bacteria.
Depending on geographic location, natural mineral water can have high concentrations of lithium. This trace mineral is commonly used to treat bipolar disorder and depression, though some studies have found a correlation between its presence in drinking water and decreased rates of suicide and criminal behavior. In some places this mineral water is sold as ‘Lithia Water’.
Purified Waters (De-Ionized and Distilled)
Several methods exist to purify drinking water of remaining contaminants, though this article describes just two: Distilled and Deionized.
Distilled water involves evaporating the liquid with heat to separate it from contaminants and then condensing the steam back into water within a separate container, usually leaving behind more than 99.9% of all minerals.
Deionized (or demineralized) water instead uses a process of ion exchange, in which electrically charged resinsreplace calcium, magnesium, sodium, copper, iron and manganese with hydrogen and hydroxyl to create pure water, free of minerals, though it may still contain bacteria and viruses.
The major case for drinking purified water is that it lacks most of the chemical contaminants and undesirable minerals that exist in tap water.
However, also absent are most, if not all, of the beneficial minerals from drinking water that supplement our diets. Due to their low mineral content, many have found purified waters to have a flat taste compared to tap or bottled water.
Drinking only purified water can also increase diuresis, dilution of electrolytes, increased elimination of minerals from the body, high blood pressure, osteoporosis, hypothyroidism, hypertension among many other things, though with a healthy diet it’s still possible to receive beneficial minerals and nutrients that are absent in purified water.
Alkaline / Ionized Water
Alkaline water is generally created with water and an ionizer, which uses an electrical current to separate H2O particles into hydrogen and hydroxyl ions, raising the pH level to around 8 or 9.
Proponents claim that alkaline water is capable of increasing vitality, slowing the ageing processes, preventing cancer and diabetes as well as neutralizing acid in the bloodstream, boosting metabolism, restoring the body’s pH balance, helping the body absorb nutrients more effectively and even offering protection against radiation.
Unfortunatelythese claims are not yet backed by medical research. Some studies have found its potential for treating acid reflux, decreasing cholesterol and helping slow bone loss, though further research is required. Another study claimed that alkaline water was effective in managing metabolic acidosis, though this was only in certain animals.
Critics argue that alkaline water may be detrimental to digestion and that it’s no healthier than regular tap water.Ionizers generally don’t filter out contaminants and mayincrease the concentration of dissolved metals to dangerous levels or even transform certain contaminants into unknown compounds.
Water ionizers can cost several hundred or even over a thousand dollars.
With a range of colors and flavors distinguishing them from other bottled water products, enhanced water is marketed as having an improved taste and being fortified with beneficial vitamins, minerals, electrolytes and herbs so as to achieve various effects including boosting energy, increasing calmness, increasing antioxidants, improving hydration as well as many other effects.
While all these things sound great, their actual health benefits have been called into question by consumer watchdogs due to enhanced waters containing high levels of sugar, comparable to carbonated soft drinks, effectively negating any potential benefits.
Featured photo credit: Bart / Flickr via flickr.com