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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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What happens when a president refuses to step down?

An approaching constitutional crisis has triggered deep political unrest in the Congo.

Franck Diongo reached his party’s headquarters shortly after 10am and stepped out of a Range Rover. Staff and hangers-on rose from plastic chairs to greet the president of the Mouvement Lumumbiste Progressiste (MLP), named after the first elected leader of the Democratic Republic of Congo.

Diongo, a compact and powerfully built man, was so tightly wound that his teeth ground as he talked. When agitated, he slammed his palms on the table and his speech became shrill. “We live under a dictatorial regime, so it used the security forces to kill us with live rounds to prevent our demonstration,” he said.

The MLP is part of a coalition of opposition parties known as the Rassemblement. Its aim is to ensure that the Congolese president, Joseph Kabila, who has been president since 2001, leaves office on 19 December, at the end of his second and supposedly final term.

Yet the elections that were meant to take place late last month have not been organised. The government has blamed logistical and financial difficulties, but Kabila’s opponents claim that the president has hamstrung the electoral commission in the hope that he can use his extended mandate to change the rules. “Mr Kabila doesn’t want to quit power,” said Diongo, expressing a widespread belief here.

On 19 September, the Rassemblement planned a march in Kinshasa, the capital, to protest the failure to deliver elections and to remind the president that his departure from office was imminent. But the demonstration never took place. At sunrise, clashes broke out between police and protesters in opposition strongholds. The military was deployed. By the time peace was restored 36 hours later, dozens had died. Kabila’s interior minister, claiming that the government had faced down an insurrection, acknowledged the deaths of 32 people but said that they were killed by criminals during looting.

Subsequent inquiries by the United Nations and Human Rights Watch (HRW) told a different story. They recorded more fatalities – at least 53 and 56, respectively – and said that the state had been responsible for most of the deaths. They claimed that the Congolese authorities had obstructed the investigators, and the true number of casualties was likely higher. According to HRW, security forces had seized and removed bodies “in an apparent effort to hide the evidence”.

The UN found that the lethal response was directed from a “central command centre. . . jointly managed” by officials from the police, army, presidential bodyguard and intelligence agency that “authorised the use of force, including firearms”.

The reports validated claims made by the Rassemblement that it was soldiers who had set fire to several opposition parties’ headquarters on 20 September. Six men were killed when the compound of the UDPS party was attacked.

On 1 November, their funerals took place where they fell. White coffins, each draped in a UDPS flag, were shielded from the midday sun by a gazebo, while mourners found shade inside the charred building. Pierrot Tshibangu lost his younger sibling, Evariste, in the attack. “When we arrived, we found my brother’s body covered in stab marks and bullet wounds,” he recalled.

Once the government had suppressed the demonstration, the attorney general compiled a list of influential figures in the Rassemblement – including Diongo – and forbade them from leaving the capital. Kinshasa’s governor then outlawed all political protest.

It was easy to understand why Diongo felt embattled, even paranoid. Midway through our conversation, his staff apprehended a man loitering in the courtyard. Several minutes of mayhem ensued before he was restrained and confined under suspicion of spying for the government.

Kabila is seldom seen in public and almost never addresses the nation. His long-term intentions are unclear, but the president’s chief diplomatic adviser maintains that his boss has no designs on altering the constitution or securing a third term. He insists that Kabila will happily step down once the country is ready for the polls.

Most refuse to believe such assurances. On 18 October, Kabila’s ruling alliance struck a deal with a different, smaller opposition faction. It allows Kabila to stay in office until the next election, which has been postponed until April 2018. A rickety government of national unity is being put in place but discord is already rife.

Jean-Lucien Bussa of the CDER party helped to negotiate the deal and is now a front-runner for a ministerial portfolio. At a corner table in the national assembly’s restaurant, he told me that the Rassemblement was guilty of “a lack of realism”, and that its fears were misplaced because Kabila won’t be able to prolong his presidency any further.

“On 29 April 2018, the Congolese will go to the ballot box to vote for their next president,” he said. “There is no other alternative for democrats than to find a negotiated solution, and this accord has given us one.”

Diongo was scathing of the pact (he called it “a farce intended to deceive”) and he excommunicated its adherents from his faction. “They are Mr Kabila’s collaborators, who came to divide the opposition,” he told me. “What kind of oppositionist can give Mr Kabila the power to violate the constitution beyond 19 December?”

Diongo is convinced that the president has no intention of walking away from power in April 2018. “Kabila will never organise elections if he cannot change the constitution,” he warned.

Diongo’s anger peaked at the suggestion that it will be an uphill struggle to dislodge a head of state who has control of the security forces. “What you need to consider,” he said, “is that no army can defy a people determined to take control of their destiny . . . The Congolese people will have the last word!”

A recent poll suggested that the president would win less than 8 per cent of the vote if an election were held this year. One can only assume that Kabila is hoping that the population will have no say at all.

This article first appeared in the 01 December 2016 issue of the New Statesman, Age of outrage