How much water do you need
And it seems we’ve swallowed the story. Last year Britons downed an astonishing 1.4 billion litres of still and sparkling mineral water a 300 per cent increase on a decade ago.
But does the idea that we need to drink, drink, drink hold water?
There’s no doubt that maintaining our fluid levels is very important. Fluid cushions our joints, keeps our eyes and mouth moist, helps us swallow, allows us to absorb nutrients, and helps get rid of waste. On top of that it helps regulate our temperature.
But do we really know how much we need to drink?
We look at some common beliefs.
Adults need to drink at least 1.5 litres of water a day.
Experts agree that around 1.5 2 litres of liquid a day is enough for most people (with more needed in hotter weather, if you exercise a lot, or do physically demanding work). But the key point here is the word liquid. Fruit juice, soup, squash and milk all count towards the total.
Dr Wendy Doyle of the British Dietetic Association says this amount is based on sound medical reasoning. Adults lose around 3 litres of fluid a day, she says: 1 1.5 litres as urine, 0.5 1 litres in perspiration, around 400ml in our breath, and about 300ml in our faeces.
But that doesn’t mean we need to drink three litres. Solid food alone gives us around a litre of liquid, and another 300 500mls of water are produced as a by product of digestion, leaving us with just the 1.5 2 litres of liquids experts recommend.
If you drink coffee, Billig Unter Rüstung Ua Slingride Tri Unisex Schwarz Kaufen Wien tea or alcohol, you need to drink even more water.
‘While it’s true that the caffeine in tea and coffee has a mild diuretic [urine increasing] effect, there is a net gain of fluid when you drink a cup,’ says Dr Doyle. ‘So you do not need to drink extra water to compensate.’
Alcohol, Billig Unter Rüstung Ua Slingride Tri Unisex Schwarz Kaufen Wien on the other hand, does dehydrate you, although usually it takes more than one glass to cause noticeable dehydration.
Drinking more water than the recommended 1.5 2 litres a day helps flush out toxins, giving you better skin, hair and nails.
False, says the British Nutrition Foundation, and Dr Doyle agrees. ‘Healthy kidneys are particularly efficient at removing toxins,’ she says. ‘Drinking more water than you actually need won’t remove any more toxins, it will just mean more trips to the loo.’
Mineral water is better for you than tap water.
False. Mineral water contains small amounts of minerals, but not enough to make a significant contribution to your diet. Tap water is no less ‘pure’ and no worse for you than bottled mineral water. In fact, a Thames Water survey recently revealed that two thirds of Britons prefer tap water to bottled water.
It’s impossible to drink too much water.
False. Drinking a lot of water (and that means more than Air Jordan 4 Kaws Retro 930155-100 Männer Weiß Grau Kaufen Wien 6 litres) over a short time can upset the body’s sodium balance, and cause a potentially fatal condition called hyponatremia, or water intoxication.
Symptoms include nausea, bloating, lapses in consciousness and seizures due to swelling of the brain.
Long distance runners and ravers who’ve taken ecstasy are particularly at risk because they often consume a lot of water and lose a lot of salt through sweat. Worse, exercise releases an anti diuretic hormone, Nike Air Huarache Laufen Extrem Unisex Weiß Austria so urine output is reduced, limiting the body’s ability to correct the imbalance. Drugs such as ibuprofen can also make the problem worse because they reduce urine output, too.
You only need to drink when you’re thirsty.
By the time you feel thirsty, you’re already dehydrated, says Dr Doyle. Usually this isn’t a problem, because we drink and replace the lost fluid. But in older people the thirst response can be blunted, leading to more serious dehydration.
Dr John Bradley, senior medical advisor to the National Kidney Research Fund says, ‘Although the kidneys can function if people drink less than one litre a day, there are huge advantages to drinking a higher level of fluid. A high fluid intake can reduce the risk of kidney stones, bladder cancer and urinary infections.’
Older people with incontinence problems should restrict their fluid intake.
False. This is a dangerous misconception, says Kiran Shukla, head of nutrition and dietetics at the South Essex Mental Health and Community Care Trust.
‘Dehydration is a common problem for elderly people, especially if they have senile dementia and live on their own. But it is very important for them to get enough liquid, especially if they are on diuretic drugs.’