Sunscreen chemicals seep into bloodstream, but impact unclear

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Sunscreen chemicals seep into bloodstream, but impact unclear

Researchers say the study is likely to have serious impact on sunscreen manufacturers.

by

Asma Ali Zain

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Published: Sun 12 May 2019, 10:39 PM

A new study has shown that chemicals from sunscreen lotion seep into the bloodstream, however, it is not clear what they do inside the body.
Researchers at the US Food and Drug Authority (FDA) last week revealed the results of a small clinical trial designed to test how four of the most common sun-filtering molecules on the market behave after they've been sprayed on and rubbed in.
The results, published in the journal Jama, show that contrary to what sunscreen manufacturers have been saying, UV-blocking chemicals do seep into one's blood circulation. However, there is no evidence yet that they're doing anything harmful inside the body.
Researchers say the study is likely to have serious impact on sunscreen manufacturers and may change the options found on drugstore shelves.
With the spotlight turned on sunscreens, authorities need to make sure such lotions don't mess up people's hormones, affect their reproductive systems, or cause cancer, according to doctors.
In the UAE, where people use sunscreens liberally, this finding could be of concern.
Dr Sonia Wilson, specialist dermatologist at RAK Hospital, however, said the research was a small-scale preliminary study that demonstrated the need for further investigation of the potential toxicities of the absorbed sunscreen chemicals.
"I would not want people to stop using sunscreens based on this one study, especially individuals with fairer skin and people who are advised sunscreens for medical reasons," she said.
People concerned about the safety of chemical sunscreens - including pregnant and nursing women, as well as children - can opt to use 'physical sunscreens' with the mineral ingredients zinc oxide and titanium dioxide.
Mineral sunscreens rely on zinc oxide and titanium dioxide to reflect sunlight from the skin, rather than absorbing it like chemical sunscreens. However, physical sunscreens may not achieve high SPF, broad-spectrum protection, and may also be aesthetically unacceptable as they could leave a whitish residue.
"It is a widely acknowledged fact that ingredients applied on the skin could be systemically absorbed. What needs to be established is, if these chemicals cause harm to the human body," Dr Wilson said.
"Currently, we know very little about these chemicals, although genuine concerns have been previously raised regarding the potential to cause hormonal disruption, allergies, cancers as well as its safety in children and pregnant women.
"Several scientific studies have sufficiently proven that using sunscreen can decrease the negative effects of sun exposure like skin cancer, allergies and premature skin aging.
Darker skin types require less use of sunscreens than lighter ones due to several inbuilt mechanisms to prevent ultraviolet damage, like a thicker epidermis and larger amounts of melanin scatter that absorb ultraviolet radiation."
A study has proven that dark skin allows only 7.4 per cent of UVB and 17.5 per cent of UVA to penetrate, whereas fairer skin allows 24 per cent UVB and 55 per cent UVA to pass through.
"However, it should be kept in mind that aggressive presentations of skin cancer are more often seen in darker skin groups," Dr Wilson said.
She added that sunscreen is just one part of sun protection methods.
"The first line of defence should be avoiding exposure to sun during peak hours between 10am and 4pm, staying in the shade, covering up with clothing, broad-brimmed hats, umbrellas and UV-blocking sunglasses," she said.
Dr Ahmed Mohsen Ahmed Ameen, specialist for dermatology and venereology at New Medical Centre, said there is a systemic absorption of any topical application directly applied to skin.
"The percentage of this absorption will vary according to many factors, such as the amount, concentration, duration, body surface area and vehicle of the topical agent," he said.
"For example, if you applied a thick layer of cream all over the body for three hours, the systemic absorption will be definitely different from applying a thin layer of lotion to the face only," he said.
He said scientific organisations, such as the FDA, should revise the guidelines for the usage of such products and balance the safety and efficacy after a number of studies with bigger sample sizes are done.
asmaalizain@khaleejtimes.com


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