Last year I wrote an article on hydration, the signs of dehydration and how much water we need to drink each day. We now know how much water to drink but what water is best? I found a great little book called “Healthy Water for a Longer Life” by Martin Fox. It reviews an extensive body of research carried out on the effects of the quality of water on health. Although it was published in 1986, I don’t think there exists a more comprehensive book on the subject. What follows is a summary of the main points.
High levels of water hardness and total dissolved solids have been linked with decreased cardiovascular disease. Hard water is water that has high levels of calcium carbonate or magnesium carbonate. In areas with hard water, you’ll notice your kettle fur up pretty quickly and in areas with soft water you’ll find it harder to wash off soap when showering. British studies have suggested hardness of at least 170 mg/l for health benefits. In the north of England, the neighbouring towns of Scunthorpe and Grimsby drank the same water for years. Scunthorpe then softened its water from 448 mg/l to 100 mg/l and Grimsby continued with the same water as before. This led to a striking increase in cardiovascular disease in the town that softened its water!
No correlation between sodium levels in water and hypertension or mortality has been found. This is probably because only 10% of our sodium intake comes from water and the rest comes from food. So avoiding processed foods and not salting our food has a bigger impact on our health.
Increased water hardness, increased total dissolved solids, increased pH and increased silica (SiO2) are each linked to decreased risks of cancer.
Fluoride is thought to prevent caries but its use is controversial due to the risk of cancer, genetic damage and birth defects. Water fluoridation has been abolished in most of Europe but continues in some parts of North America. High levels of water hardness and total dissolved solids can negate the deleterious effects of naturally occurring fluoride. Studies of dental caries in primitive groups have found that a healthy unrefined diet leads to healthy teeth.
Chlorination of water has saved countless lives by killing harmful bacteria but it has also led to an increase in atherosclerosis, heart disease and cancer. This is thought to be caused by a release of free radicals.
Animal experiments have shown that hard water provides protection from potentially harmful agents such as cadmium, lead, chlorine and dietary fat. An interesting calcium-chlorine relationship has been found. Pigeons were fed a diet that contained only 80% of the recommended daily allowance (RDA) of calcium. Half the birds were given unchlorinated water and the rest drank water that contained 10 mg/l of chlorine. Three months later the pigeons that drank chlorinated water had blood cholesterol levels that were 50% higher than the group that drank unchlorinated water. Further tests showed that pigeons given a normal diet show no differences in cholesterol levels between those that drink chlorinated water and those that don’t. When 10% lard is added to a calcium deficient diet, pigeons that drink unchlorinated water only have a minor increase in cholesterol but those that drink chlorinated water have cholesterol levels that increase about 3 fold!
Some people claim that demineralised water is better for health but there is no rationale or scientific study to support its benefits. In fact, the reverse is true…soft water is hazardous to health. Minerals with beneficial effects are: silica, magnesium, chromium, lithium, vanadium, calcium and zinc. Interestingly, mineral absorption is greater from drinking water than from food and protein enhances the absorption. If essential elements are present in water, there is less absorption of non-essential (toxic) elements.
Finally, which water is best? It has to have a presence of essential minerals and an absence of harmful minerals and compounds. Tap water may be suitable but one would have to verify its composition with the water company…a water filtration system may be required to remove harmful compounds (inorganic and organic)…the quality of filtration systems varies widely…and one has to be careful to avoid a build up of bacteria within the filtration unit…
By far the easiest option is to select bottled mineral water that satisfies the following criteria:
- approximately 300 mg/l of total dissolved solids
- around 170 mg/l hardness (calcium carbonate)
- an alkaline pH (over 7)
Drink 1.6 litres (women) to 2 litres (men) of water a day
Our bodies are 50-60% water. Water is the most essential of all nutrients. It plays an important role in the regulation of blood pressure and body temperature. It is crucial for digestion and it cushions and lubricates the brain and joints.
Two to three litres of water are lost every day through breathing, urinating, defecating and perspiring. Naturally, the quantity of water loss will depend on temperature, humidity, clothing, exercise, etc. A water loss of more than 1% of our body weight is accompanied by a decrease in physical and mental performance. The signs of mild dehydration are: thirst, headache, weakness, dizziness and fatigue. Moderate dehydration leads to a dry mouth, decreased urination, sluggishness, a rapid heartbeat and a lack of skin elasticity.
Although our sensation of thirst usually keeps us normally hydrated, the declining ability to detect thirst with age makes dehydration more common in the elderly. I remember telling my grandfather that he needed to drink more and his response was that he didn’t like it because it made him have to get up…and walk to the toilet! The colour of our urine is one of the best indicators of hydration. Straw coloured urine is ideal. The darker the urine, the more we need to drink.
It is recommended that we take in 2 litres (women) to 2.5 litres (men) of water a day (80% of the replacement water comes from what we drink and the remaining 20% comes from our food). Obviously our intake should be increased if we exercise vigorously.
Most of the information used in this article came from the European Hydration Institute. They are truly a one stop shop on hydration…and they even have a tool that allows you to compare the colour of your urine! Just in case you were wondering…