New research raises a question mark over additives used in some skin creams, particularly the implications for eczema sufferers.
Doubts voiced over skin-cream ingredients
Then last week, a story surfaced in the news concerning sodium lauryl sulphate (SLS), a detergent widely used in personal care products, after a research study published in the British Journal of Dermatology found that it may damage skin.
Scientists at the University of Bath in England had found that continued use of aqueous cream, frequently prescribed to relieve the symptoms of eczema, could worsen the condition as a result of the SLS contained in it. Aqueous cream is recommended by doctors as a moisturiser for dry skin conditions, but researchers found that after four weeks of use on volunteers, none of whom had eczema, the SLS had thinned the outer layer of the skin by 10 per cent, making it more susceptible to irritation by other chemicals.
Professor Richard Guy, who led the research, said that the study had shown that rubbing aqueous cream containing SLS into the skin affected a thin layer of fats that lie at the top of the skin and act as a protective barrier for it. This made the skin more susceptible to irritation by chemicals, and he concluded that the use of this cream on eczemous skin, which is already thin and vulnerable to irritation, was likely to make the condition even worse.
Will Evans, the co-founder and technical director of the Purist Company, which produces the A'kin range of cosmetics, all free of parabens, sulphates and phthalates, also warns about SLS.
"Sodium lauryl sulphate is a strong irritant," he says. "It is used as an irritant standard against which other irritants are measured. SLS enhances the penetrative effect of creams which upsets the natural protective barrier function of the skin."
So what of the other suspects? Used in a wide range of toiletries and cosmetics, parabens are chemicals used as preservatives to prevent the development of mould. Concern about them derives from the fact that they have been shown to act similarly to the female hormone, oestrogen, raising fears of a link to breast cancer.
A study published in 2004 in the Journal of Toxicology sought to establish a link between parabens and breast cancer, and detected parabens in breast tumours. This gave rise to a scare, largely spread by email, that parabens in underarm deodorants caused breast cancer.
However, the study has since been widely criticised by the US Food and Drug Administration and groups including the American Cancer Society and Cancer Research UK for being flawed in its execution and failing to prove that any link with breast cancer exists.
While parabens do mimic oestrogen, the FDA says they have much less oestrogenic activity than the hormone naturally occurring in the body and there is no reason for consumers to be concerned about the use of cosmetics containing parabens.
Jessica Harris, a senior health information officer at Cancer Research UK, says that while certain chemicals used in cosmetics have been linked to cancerous changes in lab experiments, it's a mistake to assume that they have the same effect on people who use these products.
"Many of these studies often use doses far higher than anyone would be exposed to to in real life," she says. "In fact, the levels of these chemicals in toiletries and cosmetics are strictly regulated for safety, and the best scientific evidence we have shows that there is no link between parabens or SLS in cosmetics and changes in cancer rates in people."
However, for eczema sufferers, there could be a reason to avoid products containing parabens, which can make certain types of skin irritation worse. Evans argues that it is prudent to move to natural cosmetics. "The jury is out on parabens," he says. "There are still scientific studies to be done, but we like to take the high ground and so we don't use parabens or raw materials that have been preserved in parabens. A lot of these ingredients are marginal in safety terms. So why not keep them away from people and use ingredients we know are safe?"
For consumers, that's easier said than done. Not all toiletries labelled "organic" or "natural" offer a chemical-free alternative. Nils El Accad, the chief executive of the Organics Foods & Café in Dubai, explains: "A lot of people cheat in organics. You can have the word 'organics' as part of your registered trademark from an old registration and produce cosmetics that have no organic element to them whatsoever. Organic legislation varies too much. Organic food is pretty well regulated, but cosmetics is the sore thumb of the industry."
He advises consumers to look out for the proportions of organic ingredients that are included in a product. "It can range from 15 per cent to 100 per cent. I sell A'kin cosmetics, Dr Hauschka and Santé, which are natural, not organic. Don't read the marketing, get some information, educate yourself. You are going to use shampoos, creams etc for the rest of your life, so research it."
Advice on SLS
In response to the new research on the use of aqueous creams containing sodium lauryl sulphate, the UK's National Eczema Society recommends that anyone using such products frequently in the treatment of eczema should switch to an alternative such as white soft paraffin (also known as white petroleum jelly) or other types of emollient with low levels of sodium laurel sulphate. (If in doubt, check with your pharmacist.) Also commenting on the report, Professor Michael Cork, an academic dermatologist from the University of Sheffield, goes one further and advises that sufferers stick to emollients that contain no SLS whatever. In a statement to BBC News, he said that despite official advice not to prescribe or recommend aqueous cream for use as an emollient, it was still widespread practice to do so. He also said that while any thinned, damaged skin would grow back eventually, using aqueous skin on it every day meant it simply would not get the chance.