How much water should we drink?

We often hear claims that we should drink 2 litres of water a day or 8 glasses.  Many of us do not drink this much perhaps because we find it difficult to include water throughout the day unless we feel thirsty.  We may also be drinking other fluids throughout the day such as teas and coffees and so will then not feel like water.  In winter, we will feel the need for drinking much less and so will not be giving our body the necessary water.

The British Nutrition Foundation states that:  Water is essential for life and it is very important to get the right amount of fluid to be healthy. However there are lots of mixed messages about how much, and what to drink and this can be confusing.  The BNF goes on to state:

Why do we need water? Your body is nearly two-thirds water and so it is really important that you consume enough fluid to stay hydrated and healthy. If you don’t get enough fluid you may feel tired, get headaches and not perform at your best. ‘Fluid’ includes not only water from the tap or in a bottle, but also other drinks that give you water such as tea, coffee, milk, fruit juices and soft drinks. You also get water from the food you eat – on average food provides about 20% of your total fluid intake.

The amount of fluid we need depends on:

• the weather (summer makes us need more water)
• how much physical activity you do (intensive exercise requires you take more fluids)
• your age (children need plenty of water and should be encouraged to drink water especially if they are active)
• any illness you might be suffering which might require more fluids
• breastfeeding mums should drink more
• Generally you should drink about 1.2 litres (6-8 glasses) of fluid per day (on top of the water provided by food you eat). You can get water from nearly all fluid that you drink, apart from stronger alcoholic drinks such as wine and spirits.

So how much should we drink in all:

Our body needs about 2.5 litres of total fluids daily (drinking water and from food and other drinks) - this is because we lose around 1.5 litres through urine output and lose another litre through breathing, sweating and bowel movements.

What type of liquids can we drink to make up these 2.5 litres?

Water is the best choice since it provides us with no calories and does not harm our teeth.  Other drinks may provide us with vitamins and minerals but they may also provide us with calories.  Therefore it is important that if we are drinking teas and coffees we take these in moderation and without sugar or fatty milk.  Milk contains a lot of essential nutrients and is good as long as we take the low fat variety and fruit juices are good too as long as they are 100% fruit juice and preferably fresh.  Some drinks are acidic such as carbonated drinks and fruit juices and so may cause erosion to the tooth enamel if consumed frequently.  The consumption of these drinks should be limited.  Drinking alcohol increases the amount of water you lose in urine and so these are not the best choice of a fluid to keep you hydrated.  We all know that alcohol consumption should be kept within recommended limits of not more than 2 - 3 units per day for women and 3 - 4 units per day for men.

Food gives us fluids too - we get as much as 20% of our total water intake from food.  Fruits and vegetables have a higher water content and these can give us up to 80% as do soups and stews.

How can I tell if I am getting enough water? Feeling thirsty is your body’s way of telling you that you need to drink more.

You can also tell through the colour of your urine:

• If your urine is a dark yellow colour during the day then you are not getting enough.
• If you are getting enough water your urine should be a pale straw colour.

Sparkling Vs Still Water

Water is a good agent to detoxify our body, that is it helps in flushing out of the body toxins via urine and sweat.  Still water is beneficial for this.  Sparkling water on the other hand is carbonated water which means it is plain water which has had carbon dioxide passed through it.  This results in the formation of carbonic acid which is normally associated with tooth decay.  Although this risk exists with sparkling water too the risk is much less than with soft drinks.  It therefore causes less erosion on teeth than soft drinks.  Sparkling water has its benefits too.  The Journal of Nutrition has quoted studies which have been done with women who had been asked to drink sparkling water and compared with other who had been asked to drink plain water.  The ones who drank sparkling water had been found to reduce their levels of low density lipoproteins (the bad cholesterol that cause risk to heart disease) and increased the levels of high density lipoproteins (the good cholesterol which can reduce the risk of heart disease).

The mantra should be that our body will always need plain still water and the less ingredients there are in it the better.  So although a moderate amount of sparkling water may be fine, one should as much as possible always opt for still water.  One should definately avoid the flavoured still water which have emerged recently as those contain a lot of sugar.

Karen Mugliett