Trendy electrolyte drinks could be putting consumers at risk of high blood pressure and kidney damage, experts are warning.
The supposedly healthy drinks have exploded in popularity in recent years, with millions now using them as part of their daily routine in the belief they will keep them better hydrated.
But kidney and heart experts say many contain significant amounts of sodium – the main constituent of salt – which can raise blood pressure and, over time, damage the kidneys.
The concern is particularly acute because millions of Britons are already living with high blood pressure or kidney disease without knowing it – meaning they could unwittingly be making an existing problem worse.
Typically, 500ml of electrolyte drink contains about 320mg of sodium – more than twice as much as a standard bag of ready-salted crisps. That is equivalent to about 0.8g of salt. Britons already consume some 8.4g of salt a day on average – well above the recommended maximum of 6g – meaning a daily electrolyte drink could push intake higher still.
Simon Davies, Emeritus Professor of Nephrology at Keele University and a trustee of Kidney Research UK, says: ‘Just as people shouldn’t have too much salt in their diet, I would advise caution with electrolyte drinks.
‘The danger is that consuming a lot of extra sodium every day in a drink can increase blood pressure, which can then damage the kidneys. Damaged kidneys are not as efficient at removing excess salt, so blood pressure rises even higher and the kidneys are damaged even further – and so on and so on, in a vicious circle.
‘What’s worse is that people may not realise the damage has been done until the problems are already well advanced.’
Millions now use electrolytes as part of their daily routine in the belief they will keep them better hydrated
Electrolyte drinks were originally formulated to replace salts and fluids lost by athletes during prolonged, strenuous exercise, or by people suffering from illnesses involving vomiting or diarrhoea.
But they are becoming an everyday wellness product, marketed as a way to improve hydration and maintain optimal levels of minerals such as magnesium and potassium. They are now available in almost every supermarket, corner shop, garage and chemist, either ready-mixed or as soluble tablets and sachets of powder.
Waitrose has reported a 171 per cent jump in searches for ‘electrolytes’ on its website over the past year, while Tesco has almost quadrupled its range of such products over the same period.
Professor Davies says: ‘The marketing suggests we need these drinks for hydration. But we’ve managed to survive on the planet for a very long time without them. For most people, they are simply not necessary.’
The boom does have some basis in science.
Electrolytes are minerals that carry a tiny electrical charge when dissolved in the blood and other body fluids and are vital for the proper functioning of cells in the muscles, heart and brain. They can also help the body absorb and retain water. However, Kidney Research UK says about seven million people in Britain are living with some level of chronic kidney disease. Five million of those are undiagnosed.
For these people, drinking extra sodium may be particularly problematic because damaged kidneys are less able to remove excess salt and fluid from the body, which can then drive blood pressure higher.
High blood pressure itself can then further damage the delicate blood vessels in the kidneys, creating the vicious circle described by Prof Davies.
Electrolyte drinks were originally formulated to replace salts and fluids lost by athletes during prolonged, strenuous exercise, or by people suffering from illnesses involving vomiting or diarrhoea
And the problem can remain hidden for years.
High blood pressure, dubbed a ‘silent killer’ because it typically causes no symptoms while damaging vital organs, affects some 14 million people in the UK.
Tracy Parker, nutrition lead at the British Heart Foundation, says: ‘The high levels of sodium in some electrolyte products can raise blood pressure – which is a major risk factor for heart attack, stroke and heart failure.
‘In the UK, most of the salt we eat is already hidden in everyday foods, so adding more through supplements may do more harm than good.’
In some circumstances electrolyte drinks can be useful.
Prof Davies explains: ‘Serious physical exercise like running a marathon or doing high-intensity training in the gym can mean losing a lot of salt through sweat. This can lead to cramps, or feeling dizzy or faint because of a drop in blood pressure.
‘Someone can also lose a lot of salt if they’ve been really sick or had bad diarrhoea. In these cases, it can make sense to take an electrolyte drink.’
For most people going about their normal day, plain water is all that is required to stay hydrated.
And rather than relying on drinks and supplements for potassium, calcium and magnesium, Prof Davies says these minerals are better obtained through a varied diet rich in fruit and vegetables, beans, nuts and seeds.
He says: ‘There is simply no argument for taking electrolyte drinks on a daily basis.
‘A lot of people slosh them back as a health enhancer – but there’s no evidence they have any benefit to health at all. The best you can say is that for most people these drinks won’t do any harm – as long as they have good enough kidney function to deal with them.’
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