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Got a cold? Eat caterpillars

Why medinical zinc is not all it's cracked up to be.

How’s this for impact? At the end of January, a research group in Manchester published a paper on the essential role of zinc in the human immune system. A week later, the price of zinc rose on the international metals markets after its longest slump in 25 years.

Amazing? Of course not. These are two entirely unrelated events. But it’s the ability to separate coincidence from causality that allows us to distinguish old wives’ tales from useful information.

Zinc has been in medical use since at least the 2nd century BC. A set of pills found in the remains of a ship wrecked off the Tuscan coast in 140BC are 75 per cent zinc. They were almost certainly used to treat eye and skin disorders, a practice documented by the Roman polymath Pliny in the 1st century AD.

Zinc is still used for this purpose. It has antiseptic and antiviral properties, which is why it is often embedded in dressings for wounds. What’s more, anecdotal evidence has long suggested that taking zinc supplements helps fight the common cold. But anecdotal evidence isn’t the most trustworthy: sometimes it sees cause and effect where there is none.

Even individual studies haven’t been enough to give us the answer; depending on how they are carried out, they can produce conflicting results. Fortunately, we’ve developed even more sophisticated techniques: dissection, analysis and pooling of the scientific studies themselves. This has allowed us to draw a firm and reliable conclusion. In the case of zinc, it’s this: take at least 75mg a day and “there is a significant reduction in the duration of cold”, according to a gold-standard Cochrane Review, which looks at primary research in health care. Ancient wisdom, in this case, has some validity.

What the ancients didn’t know is the mechanism involved. Zinc deficiency, it turns out, causes more than 3,000 types of protein in the body to function inefficiently or not at all. The body responds to this as stress, causing the immune system to leap into action. Specifically, according to researchers at Manchester University, zinc deficiency unleashes a molecule called interleukin-1-beta. This is part of the armoury of the immune system. The trouble is that, in the absence of any infection to clear, firing the immune response’s weaponry just causes damage.

The zinc deficiency, as the researchers point out, could easily be resolved using dietary supplements. And this increased medical use of zinc could have an economic impact.

Not, it has to be said, in the metals markets, where the rising price of zinc is linked to China’s construction boom. But zinc use for medical purposes could be worth about $25bn a year in the US alone. That is the estimated annual impact of common colds, in terms of lost productivity. The Cochrane Review has found that taking zinc supplements for at least five months can reduce that. It certainly reduces school absences and the prescription of antibiotics for children with the common cold.

Because colds are caused by a virus, antibiotics do nothing for sufferers, yet doctors prescribe them as a placebo to get worried parents out of their surgery. So zinc supplementation also slows the spread of antibiotic resistance. Here’s a final tip in case the price of zinc lozenges skyrockets: a daily 100g of cooked caterpillars contains all the zinc you need.

You’re welcome.
 

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 19 February 2014 issue of the New Statesman, The Space Issue

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Is the Great Fire of London a blueprint for how governments deal with disasters?

Visible leadership, an established authority, and a common external enemy: an enduring defence mechanism 350 years on.

In 1968, the science journal The Lancet ran a report into human behaviour. When populations are confronted with disaster, it recommended, effective “communications, coordination, and control, and the establishment of a recognised authority” are of utmost importance (advice that should have been heeded immediately after the Brexit result in June this year).

The 350th anniversary of the Great Fire of London this week seems is a good time to think about how we deal with disasters: over 13,000 homes were destroyed, 87 churches ruined and thousands of Londoners displaced.

For me, one of the most striking parts of the story of the Great Fire is not the fire itself nor the dramatic rebuilding programme that followed, but the state of flux in between.

When the fire broke out, England was at war with both the Dutch Republic and France. As soon as news reached France, the Venetian ambassador Alvise Sagredo, declared that the fire would be “worse than the plague and any other disaster, capable of making [the English] change their government and their principles”.

In England, even the London Gazette warned that England’s foes would try “to persuade the world abroad of great parties and disaffection at home against his majesties government”. Faced with unparalleled destruction and unprecedented disarray, how did the king, his advisers and civic authorities regain control of London?

With the Guildhall severely damaged and the Royal Exchange destroyed, the first step was to find a new base for civic and mercantile power. On 6 September, Charles II instructed the Lord Mayor and the city aldermen to resume governance of the city. Gresham College and buildings around Bishopsgate were taken over and efforts were immediately taken to re-establish trade. Vendors were granted permission to set up sheds in temporary markets at Bishopsgate Street, Tower Hill, Smithfield and Leadenhall Street.

“Honest and able persons” were selected to monitor the ruined city to ensure fire did not break out afresh, appeals were made across the country for charitable donations and neighbouring counties were called upon to provide sustenance. From the navy stores, ship’s biscuit was offered to the needy and canvas was provided so that the tens of thousands of homeless people stranded in the fields surrounding London could fashion tents.

The measures were not perfect. Visiting Moorfields, the diarist John Evelyn described, “the poor inhabitants . . . some under tents, some under miserable huts and hovels, many without a rag”.

Those stranded found food to be in short supply and many succumbed to the illnesses bred by a reduced condition in life, including aged playwright James Shirley, who died in October 1666.

But it wasn’t long before people started to disperse – either leaving London altogether, finding accommodation elsewhere, or returning to the locations of their former homes and shops to erect makeshift shacks above the ruins.

In the background, the trial and execution of French watchmaker Robert Hubert, who falsely claimed to have started the fire, provided a focus for any anger and rage.

With communication ruptured following the destruction of the London Gazette printing house and the General Letter Office, rumours of plots, arson and invasions had spread almost as quickly as the fire itself. Indeed, terrible violence had broken out during the fire, with mobs targeting any “strangers” or foreign-born Londoners. One French servant, for example, reported how gangs of “English women did knock down strangers for not speaking good English. Some of them armed with spits, some with bread staffs, and the captain with a broad sword.”

When the London Gazette was released the week after the fire – after only skipping one edition of its biweekly run – it provided readers with a detailed description of the catastrophe, emphasising its accidental nature and promoting the role played by Charles II and his brother and heir, James, Duke of York, in preventing the fire spreading even further.

Against protocol, the newspaper also allowed important tradespeople to advertise their new offices: the goldsmith-bankers, for example, informed readers that they had found premises along Broad Street.

By mid-September, the etcher Wenceslaus Hollar had already begun his survey of the city and plans had been submitted to the king from John Evelyn and architects Christopher Wren and Robert Hooke, to name just a few, as to how to rebuild the capital.

Writing at the time, Sir Nathaniel Hobart, believed that the “rebuilding of the Citty will not be soe difficult as the satisfying all interests, there being many proprietors”. As such, one of the most important innovations following the disaster was the establishment of a judiciary, known as the Fire Court, to untangle the complex web of formal and informal agreements between tenants and landlords. From 1667 until 1672 the Fire Court settled hundreds and hundreds of cases.

There were certainly many bumps along the way – for a while, the City of London was plundered and inhabited by gangs. Plus, anger towards foreign-born Londoners continued; owing to his Dutch background, one Johan Vandermarsh had to fight tooth and nail to keep hold of his property on Lime Street, despite helping to save many of his neighbours’ homes.

All of this considered, there was nothing like the widespread disorder that Charles II had feared and his enemies expected. On the contrary, the visibility of the king and his brother and heir – and the convenient suspicion that the fire had been started by an external enemy – worked to bind the people to their king and settle unrest. Although hard to believe at the time, there was also the promise of “a more beautiful city”.

Rebecca Rideal is a historian, factual television producer and author of 1666: Plague, War and Hellfire.

She will be speaking at London’s Burning festival on Friday 2 September – a contemporary festival of art and ideas produced at Artichoke to commemorate the 350th anniversary of the Great Fire of London. Free to the public, it runs from 30 August-4 September.