Wed 29, May 2019
So, you’ve been led to believe that carrying a water bottle as a permanent fixture is a good thing? And that drinking two or more litres of water a day will improve your complexion and even help with weight loss?
Well, think again. Adelaide-based urogynaecologist Dr Ian Tucker says there is absolutely no evidence to show that drinking more water than the amount required to satisfy our thirst has any health benefits. In fact, excessive fluid intake can be dangerous if taken to extremes, he says.
Dr Tucker, like most medical professionals, is at pains to stress one simple point; that our thirst – and not some bottled water company executive or beauty editor - is the best guide as to how much we should drink.
It’s a simple case of arithmetic, he says; we need to take in enough fluid each day to make up for the amount we lose, which is normally about two litres.
Of the volume lost, about 1.5 litres is urine and the remaining 500ml is through breathing and perspiration. Therefore we need to consume about two litres of fluid each day.
However, most people overlook the fact that we get about one litre of fluid daily through our food (based on a normal diet comprising fruit, vegies, cereals, soups and casseroles). This means we only need to drink about one litre - about six tea cups or small glasses - to make up the difference.
“Obviously this intake will need to be varied on hot days and at times of significant exercise. But even then, the urine output should be approximately 1.5 litres a day,” Dr Tucker said.
Any liquids - including tea and coffee - are suitable for hydration, with alcohol the only exception.
“That’s because alcohol is a diuretic. But there is this misconception that coffee is a diuretic too, which is incorrect. There is no diuretic effect from coffee, except from the aspect of volume – if you drink too much of it,” Dr Tucker said.
He also warned against too many fizzy or caffeine-based drinks, which can trigger urge incontinence in some people with bladder dysfunction.
Another common misconception, he said, is the belief that increasing fluid intake improves skin tone. For this to occur, a person’s fluid intake would have to be at such extreme levels as to be deemed dangerous.
“Improved skin tone will only occur if the fluid intake is sufficient to cause generalised oedema (fluid retention), and at this level, such fluid intake becomes dangerous,” Dr Tucker said.
Like most urogynaecologists, Dr Tucker has seen the dark side of excessive water consumption. In extreme cases, excess water intake can cause hyponatremia, when the body’s salt levels drop so low the brain swells, risking seizures and even death. Excessive fluid intake can also put strain on the heart because of the increased blood volume being pumped around the body. Too much fluid can also cause peripheral oedema and worsen incontinence issues, Dr Tucker said.
He refuted the theory that drinking water helped weight loss by reducing appetite, and referred to the work of respected nephrologist Professor Stanley Goldfarb from the University of Pennsylvania. Dr Goldfarb’s 2008 review of the scientific literature about the health effects of drinking water (published in the Journal of the American Society of Nephrology) found no evidence that drinking water before meals reduced appetite.
So, next time you’re tempted to take another sip of water you don’t particularly want, don’t. Listen to your body instead.
And a quick tip. If your urine is pale lemon in colour, you can be confident you’re drinking the perfect amount.
1. Excessive urine output (polyuria) may be an indication of diabetes as the high blood sugar levels cause the kidneys to produce more urine. This leads to excessive thirst and is one of the early signs of diabetes. Seek medical advice if this is the case.
2.Older people may not get strong thirsty signals from the brain, putting them at risk of dehydration, and so should be reminded and encouraged to drink. However, the urine output should remain about 1.5 litres a day, which can be easily measured.