All fluids being equal, this overdosing on water is simply a flush-in-the-pan
IT’S the end of January and your New Year’s resolution to drink more water is wearing thin from too many inconvenient trips to the bathroom. With a closer look at your fluid intake, it could well be you can relegate this resolution to the recycling bin.
A modern mantra is that it’s a healthy habit to drink eight glasses of water a day — the alleged benefits of which seem to range from helping with weight loss to detoxifying the liver and speeding up metabolism.
While the body certainly needs plenty of fluids, none of these claims is true, and the idea that everyone needs eight glasses of water a day is based more on average intakes than on rigorous scientific evidence.
When it comes to recommendations regarding the body’s need for fluids, it’s important to note that ‘‘ fluids’’ cover more than just plain water. Fluids include milk, juice, cordial, soft drink, tea, coffee and sports drinks as well as plain drinking water. All of these beverages count toward a person’s total daily intake of fluid, meaning it’s often unnecessary to drink eight glasses of plain water if a variety of other beverages are part of your usual daily repertoire.
Another well-entrenched myth is the idea that coffee is dehydrating. In many cases, it’s believed that a glass of water needs to be consumed for each cup of coffee drunk to offset the dehydrating effects of the caffeine. However, to be dehydrating, a beverage must lead to more fluid loss than the amount gained, and research shows that this does not occur when caffeine is consumed (until over about 500mg of caffeine is ingested). To put this into perspective, an average cup of instant coffee provides 60-80mg of caffeine, while a can of cola contains around 50mg. So as long as you are having less than seven cups of coffee a day, it will count toward your total daily fluid needs.
Drinking enough fluid is important, as all biochemical reactions in the body occur in water. It’s needed to fill the spaces between and within cells, and it’s required for digestion, absorption of nutrients and for regulation of body temperature. If you don’t drink enough you can experience the signs and symptoms of dehydration, which range from headaches, fatigue and light-headedness in mild cases, to increased heart rate, muscle cramping and kidney failure in more severe cases. Over a lifetime, too little fluid can increase the risk of kidney stones, urinary tract infections and bladder cancer.
In Australia, we drink an average of three glasses of water a day. This is followed by coffee (two cups a day), tea (one cup a day), milk (one cup), soft drinks and sports drinks (one cup) and juice (half a cup). In total, this adds up to 2.3 litres a day, enough to meet requirements for good health. So it’s not the total amount of fluid that most people need to set resolutions around, it’s the types of beverages that may need modifying.
Increasing water intake while reducing soft drinks, juice and other sweetened beverages will assist in shifting those unwanted kilos — much more so than simply drinking more water. Recent research shows we are taking steps in the right direction and shifting away from sugar-sweetened carbonated beverages to more water-based beverages, including plain bottled water. Our intake of sugar from beverages has declined by 12,402 tonnes between 2002 and 2006— a significant saving of unwanted kilojoules.
So drink plenty of water, but rest assured that if you’re an average Aussie, it’s likely you’re drinking plenty of other beverages as well and that your current intake is meeting your needs. By adding eight glasses of water on top of your usual intake, it could be that your main achievement in 2008 will be spending more time in the bathroom than you ever did. Sharon Natoli is an accredited practising dietitian and director of Food & Nutrition Australia www.foodnut.com.au