Why we need to drink water

publication date: Mar 18, 2008

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author/source: Kerry Torrens

We are constantly being advised to consume two litres of fluid daily – but where did this recommendation actually come from and what does it mean in practice?

The recommendation to drink 2 litres of fluid each day originally arose from a US government report which advocated consuming “1 ml of water for each calorie of food”. This means as an average female consuming the daily 2000 calories a day you would require 2000ml (2 litres) of water (2.5 litres (2500ml) for an average male).

However, the guidelines have often been misinterpreted. Many proclaim the need to consume 2 litres of plain water in addition to other drinks whereas the guidelines actually refer to total fluid intake. This includes water in foods and beverages such as tea, coffee, juices and soft drinks as well as plain water. This is a move away from original advice that excluded tea and coffee because of its diuretic effect (put  crudely, they make you want to pee more often! FB) though choosing more hydrating fluids such as herbal teas and water or diluted juices is still the better option.

Our bodies are 70% water so it is important that we consume adequate levels of fluid because it helps cool us, transport nutrients, digest and absorb food as well as eliminate waste products. If you have lost fluids due to illness or you exercise regularly you will need to ensure you drink extra liquid.

So what about the tap vs mineral water controversy? Well apart from the obvious issue of cost and effect on the environment there are health-related issues. Tap water in this country is widely recommended as safe but some authorities do have worries as to whether it contains residues of heavy metals or prescribed medicines like antibiotics. The most cost-effective answer, if you're worried, is to invest in a water filter - a cheaper option in the long run than buying water by the bottle.

If you do buy bottled water it's best to avoid brands that are particularly high in sodium particularly if you suffer from hypertension or water retention. It is also better, though again more costly, to buy water in glass bottles rather than plastic ones because of possible contamination by phthalates and bisphenol-A from the plastics used to make them as argued on the Green Guide website.

If you're not keen on the taste of plain water here are three ways to improve the flavour and keep your fluid intake up:

• Add a slice of lemon or lime and some ice cubes to improve the temperature and flavour

• If you find water boring – make a pot of fruit tea, leave to cool and then decant into an old water bottle, chill in the fridge and enjoy in place of a sugary squash.

• Soups are a great way to maintain hydration: choose a wintery vegetable broth or a summery pea & mint or chilled gazpacho in the summer. Or, for a quick fix, make up a mug of miso soup.