Trendy electrolyte drinks could put consumers at risk of high blood pressure and kidney damage, experts warn.
The supposedly healthy drinks have exploded in popularity in recent years, with millions of people now using them as part of their daily routine, in the belief that it will keep them better hydrated.
But kidney and heart experts say many contain significant amounts of sodium — the main component of salt — which can raise blood pressure and damage the kidneys over time.
The concern is particularly acute because millions of Brits are already unknowingly living with high blood pressure or kidney disease – meaning they could unknowingly be making an existing problem worse.
Typically, 500ml of electrolyte drink contains approximately 320mg of sodium – more than twice as much as a standard bag of ready-to-eat salted chips. That corresponds to approximately 0.8 g of salt. Britons already consume an average of around 8.4 grams of salt per day – well above the recommended maximum of 6 grams – meaning a daily electrolyte drink could increase intake even further.
Simon Davies, Emeritus Professor of Nephrology at Keele University and Trustee of Kidney Research UK, said: ‘Just as people should not have too much salt in their diet, I would advise caution with electrolyte drinks.
‘The danger is that consuming a lot of extra sodium in a drink every day can increase blood pressure, which can damage the kidneys. Damaged kidneys are not as efficient at removing excess salt, which raises blood pressure even higher and damages the kidneys even further – and so on and so forth, in a vicious cycle.
“What’s worse is that people may not realize the damage has been done until the problems are well advanced.”
Millions of people now use electrolytes as part of their daily routine, believing it will help them stay better hydrated
Electrolyte drinks were originally developed to replace salts and fluids lost by athletes during prolonged, strenuous exercise, or by people suffering from illnesses such as vomiting or diarrhea.
But they are becoming an everyday wellness product, marketed as a way to improve hydration and maintain optimal levels of minerals like magnesium and potassium. They are now available in almost every supermarket, convenience store, garage and pharmacy, ready-made or as soluble tablets and powder sachets.
Waitrose has reported a 171 per cent increase in searches for electrolytes on its website in the past year, while Tesco has almost quadrupled its range of such products in the same period.
Professor Davies says: ‘The marketing suggests we need these drinks for hydration. But without them we were able to survive on this planet for a very long time. For most people they are simply not necessary.’
The boom does have some scientific basis.
Electrolytes are minerals that carry a small electrical charge when dissolved in the blood and other body fluids and are essential 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 that around seven million people in Britain are living with some degree of chronic kidney disease. Five million of these are undiagnosed.
For these people, drinking extra sodium can be especially problematic because damaged kidneys are less able to remove excess salt and fluid from the body, which can then increase blood pressure.
High blood pressure itself can further damage the delicate blood vessels in the kidneys, creating the vicious cycle that Professor Davies describes.
Electrolyte drinks were originally developed to replace salts and fluids lost by athletes during prolonged, strenuous exercise, or by people suffering from illnesses such as vomiting or diarrhea.
And the problem can remain hidden for years.
High blood pressure, called a ‘silent killer’ because it usually causes no symptoms and damages vital organs, affects around 14 million people in Britain.
Tracy Parker, nutrition lead at the British Heart Foundation, said: ‘The high sodium content in some electrolyte products can increase blood pressure – which is a major risk factor for heart attack, stroke and heart failure.
‘In Britain, most of the salt we eat is already hidden in everyday food, so adding more salt through supplements could do more harm than good.’
In some circumstances, electrolyte drinks may be helpful.
Professor Davies explains: ‘Strong physical exertion, such as running a marathon or an intense workout at the gym, can mean you lose a lot of salt through sweat. This can lead to cramps, or feeling dizzy or faint due to a drop in blood pressure.
‘Someone can also lose a lot of salt if they have been very ill or have had severe diarrhea. In these cases it may be useful to take an electrolyte drink.’
For most people, plain water is all that is needed to stay hydrated.
And rather than relying on drinks and supplements for potassium, calcium and magnesium, Professor Davies says these minerals are better obtained through a varied diet rich in fruits and vegetables, beans, nuts and seeds.
He says: ‘There is simply no argument for taking electrolyte drinks every day.
‘Many people call them a health promoter, but there is no evidence that they have any health benefit. The best you can say is that these drinks won’t hurt most people, as long as they have enough kidney function to handle them.”
