shows cocoa is best at soothing the throat

We've all heard that honey and lemon can help soothe a cough.

Now, however, a leading expert in cough and respiratory medicine believes chocolate is even better.

Here, Professor Alyn Morice, head of cardiovascular and respiratory studies at the University of Hull, and a founding member of the International Society for the Study of Cough, claims there is research to prove it...

Cough medicine containing chocolate is stickier and more viscose than standard medicines, so it forms a coating which protects nerve endings in the throat which trigger the urge to cough, an expert has claimed

Chocolate can calm coughs.

I know that might sound like something out of Mary Poppins, but as an independent clinician who has spent years researching the mechanism of cough, I can assure you the evidence is actually as solid a bar of Fruit and Nut.

We have just seen the results of the largest real-world study of an over-the-counter cough remedy ever undertaken in Europe.

This proves that a new medicine which contains cocoa is better than a standard linctus.

The head-to-head comparison found that patients taking the chocolate-based medicine had a significant improvement in symptoms within two days.

ROCOCO, as it was called, was a well designed study, a randomised controlled trial involving 163 patients, and the results will be published in a journal within the next 12 months.

However this wasn't the first study to show that chocolate can calm coughs.

Previously, researchers at Imperial College in London found that theobromine, an alkaloid in cocoa, is better at suppressing the urge to cough than codeine — an established ingredient in cough medicines.

This new trial medicine, which has since been licensed under the brand name Unicough, was shown to reduce both cough frequency and sleep disruption within two days.

And twice as many patients taking it were able to stop treatment early because their cough had cleared.

The idea that chocolate could cure a cough might sound a bit mad, but the ROCOCO researchers believe the benefits are primarily down to the demulcent properties of cocoa.

A new large trial has found that patients taking a chocolate-based medicine had a significant improvement in symptoms within two days - faster than other remedies, claims Professor Alyn Morice

This simply means it is stickier and more viscose than standard cough medicines, so it forms a coating which protects nerve endings in the throat which trigger the urge to cough.

This demulcent effect explains why honey and lemon and other sugary syrups can help, but I think there is something more going on with chocolate.

I’m sure it has a pharmacological activity, some sort of inhibitory effect on the nerve endings themselves.

However drinking hot chocolate won’t have the same effect as the cocoa isn’t in contact with the throat long enough to form a protective coating.

Slowly sucking on a piece of chocolate may provide some relief, but I think it is the way the chocolate compounds work with other ingredients in the linctus which make it so effective.

Apart from the cocoa itself, the demulcent effect ensures the other cough-calming ingredients — diphenhydramine, levomenthol and ammonium chloride — are in contact with sensitised nerve endings for as long as possible.

Professor Morice believes chocolate has a pharmacological activity, 'some sort of inhibitory effect on the nerve endings themselves'. While hot chocolate wouldn't have the same effect as the cough medicine, because the cocoa isn’t in contact with the throat long enough to form a protective coating, he says slowly sucking on a piece of chocolate may provide some relief

There is only one type of cough

But more importantly, both these studies show that it’s high time we abandoned the ridiculous idea that there are different types of cough, which need different types of medicines.

It’s a myth.

Variety is wonderful when we open a box of chocolates, but it’s simply confusing when consumers are confronted an array of different cough mixtures for supposedly different coughs.

From a marketing point of view it makes a lot of sense to talk about wet coughs and dry coughs, chesty ones or tickly ones - because it’s a great way to encourage people to buy more products.

But from a scientific standpoint, it is incredibly out-dated.

The idea that coughs should be categorised in this way became entrenched in the 19th century when tuberculosis was rampant.

TB patients produced large quantities of phlegm and bloody liquid.

But it can be traced back even further, to the ancient Greeks, who thought that all illness was the result of an imbalance between four so-called humours — yellow bile, black bile, blood and phlegm.

He adds it's also time we abandoned' the ridiculous idea that there are different types of cough, which need different types of medicines'

Today we know that almost all common cough is caused by an upper respiratory tract infection which often accompanies a cold or flu, and with this type of infection there is no real difference between a dry cough and one which produces a small amount of phlegm.

It’s not mucus which triggers the urge to cough, it’s the fact that the infection has hijacked the body’s defence mechanism and made nerves in the upper respiratory tract hypersensitive. This works in the best interests of the virus because it triggers the urge to cough and ensures we spread it around.

There is good evidence that some of the ingredients used in cough medicines have an effect. For instance, diphenhydramine and ammonium chloride have both been proven to relieve symptoms, but it has nothing to do with mucus or chestiness, it’s because they help calm this urge to cough.

We don’t understand all the receptors involved in a mechanism like cough — but I am absolutely convinced that in years to come we will find there is a chocolate receptor involved in this urge to cough.

We used to think that menthol was simply an aromatic, but we now know it has a pharmacological effect on certain receptors. I have no doubt the same is true of chocolate.

Unicough is available in selected Superdrug, Lloyds and independent pharmacies, £8.95.

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Professor Alyn Morice is an international authority on cough and the mechanism of cough. He identified the link between ACE inhibitors and cough, established the UK’s first specialist cough clinic and the world’s first online cough clinic.

He helped draft the British Thoracic Society guidelines on the management of cough in adults, has led the European Respiratory Society and British Thoracic Society Taskforces on Cough and is a founding member of the International Society for the Study of Cough.