Your body needs water or other fluids to work properly and to avoid dehydration. That’s why it’s important to drink enough fluids.
Water makes up about two-thirds of the weight of a healthy body.
Most of the chemical reactions that happen in our cells need water in order to take place. We also need water so that our blood can carry nutrients around the body.
However, we lose water all the time, through evaporation when we breathe and sweat. If the temperature rises or we do more activity, this increases the amount of water we lose.
We also lose water when we urinate as urine is mainly water.
To stay healthy, it is important to replace the water we lose. We can do this by drinking water and other fluids.
This topic is about water and non-alcoholic drinks. Find information on Alcohol.
How much water?
In climates such as the UK’s, we should drink about 1.2 litres (six to eight glasses) of fluid every day to stop us getting dehydrated.
In hotter climates, the body needs more than this.
We also get some fluid from the food we eat.
Signs of dehydration
When our bodies don’t have enough water, we are said to be dehydrated.
One of the first signs of dehydration is feeling thirsty.
If you think you may not be getting enough fluids, check if you have any of these other common signs of dehydration:
- dark-coloured urine and not passing much urine when you go to the toilet
- confusion and irritability
- lack of concentration
See the Health A-Z topic on Dehydration for more information.
Types of drinks
Try to choose healthier drinks as part of a healthy, balanced diet.
Many soft drinks are high in sugar. Food and drinks that are high in sugar are often high in calories, and eating too many calories can make you more likely to gain weight.
Some energy drinks are high in both sugar and caffeine.
Checking the nutrition labels on soft drinks, such as fruit juices and fizzy drinks, can help you make healthier choices. For more information, see Food labels.
Water is the healthiest choice for quenching your thirst at any time. It has no calories and contains no sugars that can damage teeth.
If you don’t like the taste of plain water, try sparkling water or add a slice of lemon or lime. You could also add some squash or fruit juice for flavour.
Milk is a good source of calcium, a mineral that helps build and maintain healthy bones.
It also contains vitamins and other minerals, and does not cause tooth decay.
For a healthy choice, choose semi-skimmed, 1% fat or skimmed milk. Limit your intake of flavoured milks, milkshakes, condensed milk and milk-based energy or malt drinks because these contain added sugar, which is bad for teeth.
Milk is especially important for young children. They should drink whole milk until they are at least two years old, because they may not get as many calories as they need from lower-fat milks.
Fruit juices and smoothies
Fruit juice and fruit smoothies contain a variety of vitamins that are good for our health.
A glass (150ml) of fruit juice counts as one of your recommended five daily portions of fruit and vegetables. But juice can only ever count as one portion a day, no matter how much you drink. This is because it does not contain the fibre found in whole fruits and vegetables.
Fruit juice also contains sugar that can damage teeth. It’s best to drink it with a meal because this can help protect teeth.
The sugars found naturally in whole fruit are less likely to cause tooth decay because the sugar is contained within the structure of the fruit. When fruit is juiced or blended, the sugars are released. Once released, these sugars can damage teeth, especially if juice is drunk frequently.
When you buy fruit juice, check the labels carefully and choose 100% fruit juice with no added sugar. These drinks count as one of your 5 a day. Watch out for “juice drinks”, which can contain as little as 5% fruit juice and a lot of added sugar, and do not count as one of your 5 a day.
Learn more about 5 a day.
Fizzy drinks and squashes
Fizzy drinks, squashes and juice drinks contain lots of sugar and very few nutrients, so keep them to a minimum.
Their high sugar content means they are high in calories, and foods that are high in calories can contribute towards becoming overweight. Cutting down on these drinks is a good way to reduce the number of calories you consume, while not missing out on any nutrients.
Likewise, getting children to drink fewer sugary drinks is a good way to reduce the amount of sugar they consume. Children who drink a lot of sugary drinks are more likely to become overweight.
The added sugar in these drinks also means they can damage teeth. If you do have sugary or fizzy drinks, drinking them with meals can help reduce the damage to teeth.
The best drinks to give children are water, milk and milkshakes without added sugar.
If you or your children like fizzy drinks, try diluting fruit juice with sparkling water instead. Remember to dilute squashes well to reduce the sugar content in the drink.
Diet versions of fizzy drinks also contain very few nutrients, so milk or water are much healthier choices, especially for children.
Tea and coffee
Tea and coffee contain caffeine, which is a stimulant. This means caffeine can temporarily make us feel more alert or less drowsy. Caffeine affects some people more than others, and the effect can depend on how much caffeine you normally consume.
It’s fine to drink tea and coffee as part of a balanced diet. But it’s important that tea, coffee or other drinks containing caffeine are not your only source of fluid.
Pregnant women should limit their intake of tea or coffee (see below). Neither tea nor coffee are suitable drinks for toddlers and young children.
Caffeinated drinks can also make the body produce more urine. Some people are more susceptible to this than others, but it also depends on how much caffeine you have and how often you have it.
Energy drinks often contain high levels of caffeine. They are often high in sugar. They may also contain other stimulants and sometimes vitamins and minerals or herbal substances.
The caffeine levels in these drinks vary, but there is often around 80mg of caffeine in a small 250ml can. This is the same as two cans of cola or a small mug of coffee.
People who are sensitive to caffeine should consume high-caffeine food and drinks only in moderation.
Energy drinks are not suitable for babies or children.
Pregnant women should limit their intake of energy drinks as they are often high in caffeine (see below). Check the labels of energy drinks as they often say that the drink is not suitable for children or pregnant women.
Sports drinks can be useful when you’re doing endurance sports and need an energy boost.
However, they are no different to any other sugary soft drinks, which means they are high in calories and contribute to tooth decay.
Unless you’re taking part in endurance sports, water is the healthier choice and the best way to replace water that you have lost.
Caffeine during pregnancy
Pregnant women should have no more than 200mg of caffeine a day. One mug of instant coffee contains around 100mg of caffeine.
This is because high levels of caffeine can result in babies having a low birth weight, which can increase the risk of health problems in later life. High levels of caffeine might also cause miscarriage.
For more detail on how much caffeine is safe during pregnancy, see Pregnancy: care with food.