麻豆社

What do we mean by “winter bugs”?

The bacteria and viruses that cause colds, flu and stomach upsets consist of tiny invisible microbes. If these microbes get into your body and start multiplying, they can make you ill. What’s more, when you get a cold it could be caused by any of a host of different viruses that all produce similar symptoms. This means that you’ll still be susceptible to many others – even if you live to 100 and catch a different cold every year.

Why do we get more colds in the winter?

Virologist Prof Wendy Barclay says we succumb to more bugs when it’s cold for a few reasons. One is that viruses are fragile when outside the body, and can be killed by strong UV light from the sun during summer. Another is that in winter we’re mostly indoors, close to other people, so bugs can more easily be passed around.

So, now we know the background to winter bugs, will these popular products help keep us healthy?

1. Hand sanitisers

Why use hand sanitisers?

Our hands carry millions of bacteria and viruses, most of which won’t do us any harm, but if we come up into contact with certain strains and they get into our bodies, they can make us ill. Hand sanitisers – usually gels or liquids that you rub on your hands – claim to kill the majority of germs on our hands with the aim of protecting us from the harmful ones.

Greg Foot holds some of the hand sanitisers he tested in his podcast, The Best Thing Since Sliced Bread?

Do they work?

Many hand sanitisers claim to kill 99.9% or more of bacteria and viruses. This may sound like a lot, but because a clean-looking hand can harbour millions of germs, you could still be left with several thousand potentially disease-causing microbes.

So, although hand sanitisers can reduce the risk of you becoming ill, they can’t eliminate it since some germs will always be left behind – and it only takes a few misplaced microbes up your nose to cause a cold.

Also, standard laboratory tests pit sanitisers against a specific range of common bacteria and viruses, but they can’t test every microbe species because there are just too many out there. So although they may work against some germs, they could be completely ineffective against others.

So, are they worth trying?

There are places that we know can harbour high levels of bacteria and viruses, such as schools and hospitals. Many people argue that using hand sanitisers in these settings can help reduce the spread of disease. Or if you’re, say, changing a baby’s nappy in the outdoors when you have no access to soap and water.

However, while hand sanitisers may kill germs that could make you unwell, our hands also carry good bacteria that support our immune system and help us fight infection, and hand sanitisers wipe most of these out too. Microbiologist Dr Lindsay Hall says a significant body of evidence is emerging to suggest that “these microbes are fundamental for basically making us healthy day to day.”

What’s more worrying, Dr Hall says, is evidence which suggests the chemical compounds in some alcohol-free sanitisers may contribute to antibiotic resistance – where bacteria develop the ability to survive and then breed new, tougher, more dangerous strains. One compound – benzalkonium chloride – which is used widely in antibacterial hand soaps is currently under investigation in the US. Another compound – triclosan – has already been banned for use in hand sanitisers in both the US and the EU.

2. Vitamin C

Why take vitamin C?

Vitamin C acts as an antioxidant in the body and has been used as a cold cure for centuries. Many people swear by it as a way to prevent colds or stop them in their tracks.

Does it work?

A major review of multiple studies (by the British charity Cochrane) found that taking regular vitamin C supplements had no effect on the number of colds people caught. (The only exception was among skiers and marathon runners – the theory is that their bodies are under more stress and so could benefit from the antioxidant effects of vitamin C. However, this explanation hasn’t been scientifically proven.)

Taking regular vitamin C has been found to reduce the length of colds by 8% in adults or 14% in children – that’s around half a day. But the evidence suggests you’d need to be taking it daily for nine months to see an effect – and since most people get one or two colds a year, it might not be worth it.

Many people take vitamin C at the first sign of a cold but studies into this “therapeutic” use have had very variable results. One large trial did report a benefit from taking a very large, eight-gram dose when participants first got cold symptoms.

So, is it worth trying?

Taking regular vitamin C won’t stop you getting ill but it might slightly reduce the length of your cold.

Therapeutic vitamin C could be more effective at shortening your illness. However, given that one large orange contains only around 100mg of vitamin C – and you’d need 3g for an adequate dose – you’d have to eat at least 30 oranges on the first day of your cold! And waiting even a day will reduce the benefit even more.

It’s also important to note that vitamin C shouldn’t be taken by people with kidney disease or certain genetic diseases. And if you decide to take any new supplement, you should consult your doctor first.