Can an hour in a salt cave cure your ills or is it just a con(diment)?

The crisp white powder crunches under foot, stacks of crystalline rock sparkle and ‘icicles’ glitter from above. No, it’s not a secluded Alpine cave but a clinic in West London.

The white powder isn’t snow, it’s salt. So are the icicles and the rocks piled in the corner. I am standing in the Adalex Clinic’s recently-opened ‘salt grotto’.

The grotto (actually, it’s less of a ‘grotto’ than just a plain old room with assorted sun loungers) is the brainchild of Grace Hart, a former psychologist.

Magic grotto? A sceptical Alice-Azania Jarvis chills out in the salt cave in West London

She says that such grottos are commonplace in her native Poland, and claims that a spell in its salty confines — a typical session lasts an hour and costs £25 — offers all manner of health benefits, from relieving asthma to improving blood circulation and lowering blood pressure.

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Above all, after an hour in the grotto I should experience, she says, a sense of ‘psycho physical comfort’. Which definitely sounds like a good thing — even if I’m not entirely sure what she means by it.

Actually, quite a lot of what clinic manager Grace says about the health benefits of the salt grotto doesn’t bear close scrutiny.

‘It’s about feeling good, mentally and physically,’ she tells me. ‘You will feel calm and refreshed, and you won’t have any anxiety.’

Benefits: Salt is rich in minerals such as iodine, potassium and bromide

The apparently miraculous power of salt is all, she says, down to its ‘micro-elements’.

Salt is rich in minerals such as iodine, potassium and bromide. Usually, we get these by eating it — but Grace believes we can absorb them by sitting in a room full of the stuff.

‘We are depleted of micro-elements because our water is polluted, our diet is bad. But micro-elements like bromide have a calming effect on the brain. If you are stressed out, you can become calm in a natural way.’

As well as a new-found sense of calm, after an hour in the grotto, she promises, I should feel reinvigorated and healthy.

‘The air is very clean inside the grotto — ten times cleaner than normal air,’ she continues. ‘Salt is anti-fungal and anti-bacterial. You start breathing slower and deeper as the salt opens up your bronchial airways. You breathe better and you feel better.’

While it may sound like bunkum (OK, it definitely does sound like bunkum), in Central and Eastern Europe they have been using salt grottos — both natural and artificial — for donkey’s years.

The first was set up 150 years ago after Dr Feliks Boczkowski, a Polish physician from Wieliczka, near Krakow, noted that local salt miners didn’t suffer from lung diseases. A natural grotto was carved out within the Wieliczka mines themselves, 400 feet underground. It became popular with those suffering respiratory disease, and is still in use today.

Before I’m allowed into Grace’s grotto, she hands me a pair of blue plastic shoe covers to protect both the salt and my shoes.

To keep the salt fresh, it is regularly topped up from the stash of enormous 25kg sacks kept in a storage room at the back.

And it definitely is salt. After Grace closes the grotto’s outer door and leaves me alone, I taste a pinch just to be sure.

The PA system in the corner plays a pan-pipes version of Just The Way You Are, while angled lamps make the salt look rosy pink, with blotches of blue on the ceiling and orange stripes along the walls.

Believer: Former psychologist Grace Holt says an hour in the salt cave offers all manner of health benefits

It’s a little like being in a Seventies nightclub. Nevertheless, after 20 minutes in the cave, the promised sense of calm is indeed descending. In fact, I’m starting to nod off. I’m seated on a squishy sun lounger and wrapped up in a snuggly blanket which Grace has provided.

Though there are magazines in the waiting room, in the grotto there’s nothing to do but drift in and out of sleep. Clients are asked to leave their mobile phones behind.

There is a soporific sound of gently trickling water coming from what looks like an enormous garden water feature. This, explains Grace, is the grotto’s ‘evaporation tower’.

A good six feet high, it features an artfully-arranged fan of salt-encrusted twigs inside a giant wooden display case. Water flowing from a tank concealed within the tower’s wardrobe-like structure is trickling over them. It’s brine, brought over from Poland, Grace tells me.

‘It is one of the most healthy, healing waters,’ she says. It is a very special mineral water. Sitting near it as it flows, many of your positive ions will change to negative ions, which always make you feel better.

‘In the city, there are a lot of positive ions — which make you feel anxious, angry and agitated.

Tranquil: Though there are magazines in the waiting room, in the grotto there¿s nothing to do but drift in and out of sleep

Negative ions make you feel refreshed and fantastic.’

From what I can remember of GCSE physics, ions are simply atoms or molecules with positive or negative electrical charges. Why they should leave you anxious or refreshed eludes me.

The twigs, meanwhile, are birch — a ‘healing wood’ according to Grace. But of course!

The salt itself is equally exotic. The three tons which cover the floor have been brought from Poland, while the rocks lining the walls and piled at the corners are Himalayan salt imported from Pakistan.

According to Grace: ‘Not every salt has all the special properties. Himalayan salt has 84 different micro-elements.’

In total, the room contains more than 10 tons of salt. Building it took a month and cost £35,000.

There’s no doubt that lolling around in my sun lounger is a rather pleasant way to while away an hour — but how does the scientific evidence stack up? Unfortunately, there isn’t a huge amount.

‘I know of no good scientific evidence about this approach and see no reason why this should be any better than relaxing in any other quiet environment,’ says Professor Edzard Ernst, a physician and former Professor of Complementary Medicine at Exeter University.

Wendy Sadler, of Science Made Simple, an independent organisation aimed at explaining scientific research to the public, agrees — and questions the idea that exposure to ‘micro-particles’ and ‘negative ions’ can make you feel calmer and more energised.

She says: ‘There’s no reason at all you should feel calm because of exposure to negative ions. And there have been no studies that have shown mineral water will convert positive ions to negative ones.’

Neither is there much to support the myriad other health benefits salt grottos purport to offer.

Malayka Rahman, research officer at Asthma UK, says that while some sufferers have noticed short-term benefits, it is not clear whether that’s down to salt or simply the effect of an hour’s relaxation.

A couple of months ago a similar business, the Salt Cave — a company which operates a chain of grottos across the UK — was forced to remove a section of its website which claimed salt therapy could treat various ailments, including cystic fibrosis and psoriasis.

The Advertising Standards Authority concluded that there was insufficient evidence.

Inconclusive: Unfortunately there isn't much scientific evidence to support the supposed health benefits of using a salt cave

Grace is unperturbed by such naysayers. ‘There’s always a war between traditional doctors and alternative therapies,’ she says. ‘The medical world is like a Mafia. You can’t patent a natural thing like this, so there’s no money in it for them.’

And anyway, she says, business is booming. Though the clinic is ghostly quiet during my time there, Grace claims her grotto often has 30 customers a day.

Clients hoping to treat their asthma are recommended to make two or three visits a week for seven or eight weeks — at a cost of more than £400. It sounds an awful lot to realign your ions, if you ask me.

You can even hire the grotto for private parties — complete with champagne and canapés in the clinic’s sleek white reception area.

The next marketing opportunity is a new wrinkle cream made with hemp oil and (yes, you guessed it) Himalayan salt.

Grace says: ‘Salt keeps moisture in the skin and smooths it out. Look, I’m 62, but I don’t have many wrinkles.’ (It is true that she does look some ten years younger than her age.)

As for me? Well, I can’t say I experience any great transformation.

Grace tells me I should sleep deeply that night, and certainly I leave the clinic feeling relaxed. But whether that’s the salt at work or has more to do with the fact that I’ve spent an hour snoozing on a sun lounger, I don’t know.

At any rate, it was a perfectly pleasant — if expensive — way to spend a morning. As for any supposed health benefits . . . well, I’d take those with a pinch of salt.