Could using an antibacterial soap be bad for you?
After claims they’re ineffective and may also actually FUEL the rise of superbugs, we ask...
Whether it’s a splodge of hand gel after a commute or a squirt of cleaning spray on kitchen counters after cooking, chances are you are one of the millions who uses some form of antibacterial product.
they have become a handbag and household staple — sales of germ-killing cleaners hit an estimated £239 million in 2013, according to Mintel.
But do they really help protect us from getting ill and spreading germs? And could they actually be bad for us?
these are questions raised by the decision earlier this month by U.S. authorities to ban certain chemicals used in the soaps, with some British experts saying the same should happen here.
the Food and Drug Administration (FDA), which also oversees the safety and efficacy of cleaning products in the U.S., has banned the use of 19 common active ingredients in antibacterial soaps.
this includes bar soaps, liquid soaps and body washes (products that don’t use the ingredients aren’t banned, nor are hand gels — the FDA has deferred a review of three other chemicals, which may affect hand gels).
the FDA says there’s no scientific evidence these chemicals are better than plain soap and water at killing germs, and manufacturers had not demonstrated their safety for longterm use. It expressed concern that some of the chemicals may disrupt hormone levels.
Furthermore, it cited research suggesting these could also be making bacteria resistant to antibiotics.
Most people would associate antibiotic resistance with over-prescribing by doctors, but emerging evidence suggests antibacterials are also a risk.
this was confirmed by a study this month by the University of Oregon. Scientists analysed dust samples and found those that contained high levels of anti-microbial chemicals also contained genes linked to antibiotic-resistant bacteria.
In particular, they found triclosan (now banned by the FDA) affected a gene in the bacteria that helps make it resistant to several antibiotics, reported the journal environmental Science and technology.
triclosan is a powerful antibacterial used in domestic products that can also have mild anti-inflammatory effects. It’s used in toothpastes to reduce gum inflammation, for example.
the problem is the way some chemicals such as triclosan kill off bacteria is very similar to the way antibiotics do.
triclosan, for instance, targets a specific enzyme that’s involved in bacteria’s metabolism, helping keep a number of bacteria alive.
Many antibiotics also work by targeting this enzyme; these include isoniazid, used to treat tB.
So as the bacteria learn to resist the antibacterial chemical, they become resistant to antibiotics that work in a similar way.
ThIS has raised concerns that widespread use of triclosan (it’s also used in kitchenware, furniture and toys) could lead to growing resistance in bacteria.
Mark Webber, a senior research fellow at the University of Birmingham who researches anti-microbial action, says his work shows that ‘if we expose bugs to triclosan in a lab, they can become resistant to it, but worryingly also to some antibiotics’.
triclosan has also been identified as an ‘endocrine disruptor’ — meaning it interferes with hormone levels — in more than 200 animal studies, and linked to a raised risk of cancers such as breast or thyroid.
In a U.S. study in 2014, mice exposed to triclosan for six months had liver damage and were prone to liver tumours, according to the journal PNAS.
the researchers said it caused this damage via mechanisms that are also relevant in humans, and that increasingly broad use presents a ‘very real risk’ of liver toxicity, particularly when combined with other compounds with similar action.
‘the structure of triclosan is similar to chemicals called PCBs, which were banned in the Seventies for being bioaccumulative (they build up in the body over time) and toxic to humans. It beats me why it is still allowed to be used widely,’ says Professor Philippa Darbre, an adviser on the eC committee on health and environmental risks and lecturer in oncology at the University of reading.
Another chemical, triclocarban (also now banned by the FDA), which works similarly to triclosan, was shown in 2008 to raise levels of testosterone in male animals.
More recently it was shown to raise testosterone production by 130 per cent. this could harm the reproductive system and promote breast and prostate cancers.
It’s important to stress no human studies have proven a direct link, and on the whole these ingredients are safe for day-to-day use — the issue is what happens with prolonged exposure. the lack of data means no one knows. We also don’t know if the data from animal and lab studies applies to humans, too.
But a more immediate question is whether antibacterial products — or soaps at least — stop disease. the FDA suggests ingredients used in many have not been shown to do so. Most everyday illnesses — colds, stomach bugs, sore throats — are caused by viruses, not bacteria, so antibacterial products won’t protect against them (just as antibiotics wouldn’t, either).
But what about tackling bacteria? Last year, a Korean study showed that for handwashing, using antibacterial soap does not kill more bacteria than plain soap, reported the Journal of Antimicrobial Chemotherapy.
Jean-Yves Maillard, a professor of pharmaceutical microbiology at Cardiff University, suggests this may be because people don’t scrub for long enough.
‘to use anti-microbial soap effectively you have to scrub your hands for one minute for the chemicals to kill the organisms,’ he says, adding that most people wash for only ten seconds.
‘With standard handwashing, it is the mechanical removal that cleans hands straight away.’
It is the same with antibacterial gels, he says. Most people rub these in for five seconds, but the active chemicals need to be on the skin for 30 seconds to kill the bacteria.
It’s a more complicated story with alcohol-based sanitisers, which kill germs by attacking their outer membrane. these are less of a risk for antibacterial resistance because they kill bacteria in a different way from antibiotics.
to be effective they need to contain a high concentration of alcohol, and this can make hands dry and exacerbate skin problems. Manufacturers often reduce the alcohol content to make the product evaporate quickly, but Professor Maillard says fast evaporation means it’s less effective.
Given the FDA action, is it time to ban antibacterial ingredients in Britain, too?
In fact, the chemicals used in hygiene products are regulated by two different eU bodies. One has already decided to ban triclosan and triclocarban in products such as washing powders and cleaning sprays — though their use is being phased out, not stopped overnight.
With cosmetics (which under eU definition includes hand soap), triclosan and triclocarban are allowed in set amounts, but some UK experts believe that there should be a wider ban on antibacterial ingredients generally. Nigel Brown, emeritus professor of molecular microbiology at edinburgh University, says: ‘I am alarmed by the rise in resistance from widespread use of these products.
‘there is a problem with using things that are “antibacterial” for everything when they should be reserved for treating diseases in hospital.’
he says if he had to use an antibacterial product, he would ‘make sure it’s an alcohol-based one and does not contain triclosan’.
even without a ban, there is little need to have antibacterial products, says Mark Webber: ‘their use is nonsensical. Soap and water is fine. If we need to wipe surfaces at home we use bleach, which kills bacteria and doesn’t cause resistance.’
A spokesperson for the UK Cosmetic toiletry and Perfumery Association (CtPA) says: ‘In respect of the 19 chemicals included in the FDA announcement, the majority are banned under the eU Cosmetic Products regulation. the others must be safe to use otherwise they would be banned.’
Dr Chris Flower, director-general of the CtPA, adds: ‘the industry and regulators are aware of concerns regarding possible endocrine effects and if such a risk was present from cosmetic products, action would have been taken to deal with it.’