Delicious. Photo: Getty
Show Hide image

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

Photo: Getty
Show Hide image

The big problem for the NHS? Local government cuts

Even a U-Turn on planned cuts to the service itself will still leave the NHS under heavy pressure. 

38Degrees has uncovered a series of grisly plans for the NHS over the coming years. Among the highlights: severe cuts to frontline services at the Midland Metropolitan Hospital, including but limited to the closure of its Accident and Emergency department. Elsewhere, one of three hospitals in Leicester, Leicestershire and Rutland are to be shuttered, while there will be cuts to acute services in Suffolk and North East Essex.

These cuts come despite an additional £8bn annual cash injection into the NHS, characterised as the bare minimum needed by Simon Stevens, the head of NHS England.

The cuts are outlined in draft sustainability and transformation plans (STP) that will be approved in October before kicking off a period of wider consultation.

The problem for the NHS is twofold: although its funding remains ringfenced, healthcare inflation means that in reality, the health service requires above-inflation increases to stand still. But the second, bigger problem aren’t cuts to the NHS but to the rest of government spending, particularly local government cuts.

That has seen more pressure on hospital beds as outpatients who require further non-emergency care have nowhere to go, increasing lifestyle problems as cash-strapped councils either close or increase prices at subsidised local authority gyms, build on green space to make the best out of Britain’s booming property market, and cut other corners to manage the growing backlog of devolved cuts.

All of which means even a bigger supply of cash for the NHS than the £8bn promised at the last election – even the bonanza pledged by Vote Leave in the referendum, in fact – will still find itself disappearing down the cracks left by cuts elsewhere. 

Stephen Bush is special correspondent at the New Statesman. He usually writes about politics.