Your body’s superpowers

The remarkable abilities already inside us.

Norovirus might have laid you low for a short while, but you’re recovering, aren’t you? Your immune system is to die for. Researchers are still getting to grips with how it works but at every turn it has thrown out marvellous surprises. In the early days of vaccination against tuberculosis, for example, it was noted that it protected you not only from TB, but a host of other diseases, too.

We still don’t know why; it’s clear that we have yet to understand the full power of the human immune system. Just in December, for instance, we learned that the system’s T-cells, which fight viruses and bacteria, are not all created equal. Almost all of our knowledge of human T-cells has come from blood samples. But research using T-cells harvested from the organs of New York cadavers has shown that each region of the body has its own particular way of fighting invaders. Columbia University’s Donna Farber, who led the study, believes this discovery may open up the path to tightly focused vaccines that can activate the most appropriate of the body’s immune responses.

Her optimism is supported by another surprise the immune system has just delivered. New Scientist reported this month that there is now hope for a vaccine against age-related macular degeneration (AMD), an incurable condition that blinds millions of people around the world.

AMD comes from the build-up of proteins and other debris on the retina. In healthy people this is cleared away by specialist cells. Those cells stop working in people with AMD. This appears to have two consequences: the build-up of debris continues and the light-sensitive cells of the retina beneath the debris start to die off. The result is a slowly widening black hole at the centre of your field of vision.

Pioneering treatments with a laser can stimulate the nonfunctioning cells to get them going again, which is exactly what Robyn Guymer of the University of Melbourne was trying to do in his trial on 50 patients. The idea was to try the laser treatment in one eye and leave the other eye as a control. Then tests on each eye would show what improvements the procedure could give.

So, you could imagine it was a little frustrating that in the tests the lasered eye didn’t seem to be that much better than the one that had been left alone. But Guymer soon realised this was because the vision of the untreated eye had also improved. The laser surgery had stimulated the patients’ immune system to respond to alarm calls from the eye.

Your eyes are usually offlimits to your immune system. It seems a sensible evolutionary trick, because the immune system’s standard response causes inflammation, which could be catastrophic in an instrument as sensitive as the eye. However, the cells destroyed by the laser appear to send out a signal so loud that the immune system overrides the safety mechanism and sends in the troops – to both eyes – to restore order.

There is now hope that AMD can be treated with a routine procedure at a very early stage, and that those most at risk of developing it can have their immune systems stimulated before the symptoms appear. But there is a wider lesson: with various successes in vaccines against cancer – particularly colon cancer – looking likely in the next few years, it’s becoming clear that the most profitable path for medicine might be to explore partnerships with the remarkable abilities that already lie within us.

Michael Brooks’s “The Secret Anarchy of Science” is published by Profile Books (£8.99)

There is now hope for a vaccine against age-related macular degeneration. Photograph: Getty Images

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 28 January 2013 issue of the New Statesman, After Chavez

Davide Restivo at Wikimedia Commons
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Scientists have finally said it: alcohol causes cancer

Enough of "linked" and "attributable": a new paper concludes that alcohol directly causes seven types of cancer.

I don't blame you if you switch off completely at the words "causes cancer". If you pay attention to certain publications, everything from sunbeds, to fish, to not getting enough sun, can all cause cancer. But this time, it's worth listening.

The journal Addiction has published a paper that makes a simple, yet startling, claim: 

"Evidence can support the judgement that alcohol causes cancer of the oropharynx [part of the throat], larynx, oesophagus, liver, colon, rectum and [female] breast"

So what's especially significant about this? 

First, scientists, unlike journalists, are very wary of the word "causes". It's hard to ever prove that one action directly led to another, rather than that both happened to occur within the same scenario. And yet Jennie Connor, author of the paper and professor in the Preventive and Social Medicine department at the University of Otago, New Zealand, has taken the leap.

Second, alcohol not only causes cancer of one kind – the evidence supports the claim that it causes cancer at seven different sites in our bodies. There was weaker evidence that it may also cause skin, prostate and pancreatic cancer, while the link between mouth cancers and alcohol consumption was the strongest. 

What did we know about alcohol and cancer before?

Many, many studies have "linked" cancer to alcohol, or argued that some cases may be "attributable" to alcohol consumption. 

This paper loooks back over a decade's worth of research into alcohol and cancer, and Connor concludes that all this evidence, taken together, proves that alcohol "increases the incidence of [cancer] in the population".

However, as Connor notes in her paper, "alcohol’s causal role is perceived to be more complex than tobacco's", partly because we still don't know exactly how alcohol causes cancer at these sites. Yet she argues that the evidence alone is enough to prove the cause, even if we don't know exactly how the "biologial mechanisms" work. 

Does this mean that drinking = cancer, then?

No. A causal link doesn't mean one thing always leads to the other. Also, cancer in these seven sites was shown to have what's called a "dose-response" relationship, which means the more you drink, the more you increase your chances of cancer.

On the bright side, scientists have also found that if you stop drinking altogether, you can reduce your chances back down again.

Are moderate drinkers off the hook?

Nope. Rather devastatingly, Connor notes that moderate drinkers bear a "considerable" portion of the cancer risk, and that targeting only heavy drinkers with alcohol risk reduction campaigns would have "limited" impact. 

What does this mean for public health? 

This is the tricky bit. In the paper, Connor points out that, given what we know about lung cancer and tobacco, the general advice is simply not to smoke. Now, a strong link proven over years of research may suggest the same about drinking, an activity society views as a bit risky but generally harmless.

Yet in 2012, it's estimated that alcohol-attributable cancers killed half a million people, which made up 5.8 per cent of cancer deaths worldwide. As we better understand the links between the two, it's possible that this proportion may turn out to be a lot higher. 

As she was doing the research, Connor commented:

"We've grown up with thinking cancer is very mysterious, we don't know what causes it and it's frightening, so to think that something as ordinary as drinking is associated with cancer I think is quite difficult."

What do we do now?

Drink less. The one semi-silver lining in the study is that the quantity of alcohol you consume has a real bearing on your risk of developing these cancers. 

On a wider scale, it looks like we need to recalibrate society's perspective on drinking. Drug campaigners have long pointed out that alcohol, while legal, is one of the most toxic and harmful drugs available  an argument that this study will bolster.

In January, England's chief medical officer Sally Davies introduced some of the strictest guidelines on alcohol consumption in the world, and later shocked a parliamentary hearing by saying that drinking could cause breast cancer.

"I would like people to take their choice knowing the issues," she told the hearing, "And do as I do when I reach for my glass of wine and think... do I want to raise my risk of breast cancer?"

Now, it's beginning to look like she was ahead of the curve. 

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.