• bet365娱乐, bet365体育赛事, bet365投注入口, bet365亚洲, bet365在线登录, bet365专家推荐, bet365开户

    WIRED
    Search
    Search

    Doctor Explains How Sunscreen Affects Your Body

    A recent F.D.A. study shows that certain chemicals in some sunscreens can seep into and remain in people's blood. To find out what that means for staying safe in the sun, WIRED's Robbie Gonzalez spoke with dermatologist Dr. Kanade Shinkai.

    Released on 07/11/2019

    Transcript

    Summer is officially here.

    The sun is out, it is shining and,

    sorry to be a downer, but so are it's cancer causing rays.

    Everybody knows protecting their skin from the sun

    is important and most of us have heard our whole lives

    that sunscreen is the best defense for that.

    But a new study, backed by the Food & Drug Administration

    has shown that some chemicals in some sunscreens

    can actually penetrate the skin and wind up

    in your blood stream.

    So what does that mean for you and protecting

    your skin this summer?

    To find out we're talking with Kanade Shinkai,

    she's a Dermatologist at UC San Francisco

    and Editor in Chief of JAMA Dermatology.

    So, I think this study raises a lot of questions

    for people on whether they should continue

    to wear sunscreen.

    So just top line question;

    is wearing sunscreen still a good idea?

    Wearing sunscreen is still a good idea.

    And sunscreen, though, is just one part of

    protecting your skin from the sun

    and that includes seeking shade,

    trying not to do physical activities

    or activities outdoors during the peak hours of the sun,

    which are between 10 and two pm and then using

    other protective mechanisms like using hats,

    sunglasses, protective clothing,

    so sunscreen's just one part of protecting

    your skin from the sun.

    Can you tell us a little bit about what the study

    looked at and what it found?

    Yeah, so the study's a small pilot study

    that looked at the application of four different

    commercially available formulations of sunscreen,

    these are things that are available at most drug stores.

    They measured the absorption of the key sunscreen

    ingredients in the blood over time and also

    after the application had stopped and what it found

    was that there is notable absorption of the

    sunscreen ingredients into your bloodstream

    and that they reached levels,

    really just after a few hours of applying the

    sunscreen and will stay elevated for almost

    a day or two after you stop using the sunscreen.

    So this means that when we put sunscreen on our skin,

    it's getting absorbed through the skin and it's

    going into our bloodstream and it hangs around

    for a lot longer than the application and the levels

    that were found in the study were greater than

    the levels that the Food & Drug Administration here

    in the United States uses kind of as a threshold

    to do safety testing.

    But the safety testing has not been done,

    so really, what it's telling us is that sunscreen

    gets absorbed into the bloodstream,

    it reaches levels that are higher than this

    regulatory threshold and the safety testing

    has not been done yet.

    I think, when a lot of people first read about this study,

    they read oh, there's chemicals in sunscreen,

    it's getting into my bloodstream.

    Chemical has become kind of an unhelpfully broad,

    kinda scary term for a lotta people.

    They'll hear it and think oh, chemical is bad and unsafe

    and dangerous, but the fact is all physical matter

    is chemicals, right?

    So it helps to talk with specifics here.

    So what kinds of chemicals did this study find

    in people's bloodstreams?

    Yeah, well there's two different types of sunscreen.

    One type we call mineral sunscreen and these are

    literally minerals; zinc oxide and titanium dioxide,

    they coat the skin.

    Technically, you could call it sunblock.

    They also often leave a very white color on the skin

    so a lot of people don't like to use it for that reason.

    Those have been tested and don't have any

    systemic absorption so we know that those are safe.

    The other type of sunscreen is what we

    colloquially call chemical sunscreen.

    So these are literally chemical filters

    that absorb ultraviolet light and these are the ones

    that are in question, these are the ones that have

    never been tested in terms of their safety,

    or their systemic absorption, four of which were the ones

    that were studied in this particular research article.

    What ingredients, in sunscreens specifically,

    was this study looking at?

    This particular study looked at

    four sunscreen ingredients:

    Avobenzone, Oxybenzone, Octocrylene and Ecamsule.

    What do these chemicals actually do inside the body?

    Is that something we know?

    Yeah, so we don't really know.

    There's never been any research article that has suggested

    that these chemicals are doing anything harmful

    to the human body.

    There are some studies, however,

    that have been done in lavatory animals and, of course,

    take it with a grain of salt because these studies

    always use doses that are a lot higher than what

    a person would be exposed to,

    but there have been some data points that have suggested

    changes to your hormone levels,

    changes in reproduction and those have at least

    raised the question of whether or not safety testing

    should happen in humans.

    But that safety testing has not happened yet.

    Even if we take the animal studies with a grain of salt,

    I think that not knowing is still an unsettling

    prospect for people.

    So the question that I would imagine a lot of people

    are asking is; should I still wear sunscreen?

    Is it safer to be exposed to the sun unprotected,

    or to use this product on my body that

    has effects I may not fully understand?

    Yeah, well there is something absolutely certain,

    which is that the sun and sun exposure,

    and especially prolonged sun exposure can result in sunburn,

    which is unhealthy, and also can lead to skin cancer.

    That is not in question in this study.

    I think what's in question is really about

    how effective sunscreen is in protecting long-term

    from skin cancer and melanoma, as well as whether it's safe.

    A lot of consumers don't know that sunscreen's

    actually considered a medication and so because of that

    usually all over the counter medications are

    subjected to a battery of testing but that has

    never been done for these chemical sunscreens

    and that's why this study is so important.

    Why hasn't that been done for sunscreen?

    You know, sunscreens have been around for a long time

    and they really preceded, kind of the standard way

    that we evalsuate over the counter medications

    in this country and so usually in history and time

    we find out that a medication has some side effect

    that might be dangerous to people and it gets

    taken off the market, now what we try to do

    is do those safety studies in advance of the

    medication coming out.

    However, that hasn't been done for sunscreen

    because, in large part, the sunscreens predated

    that type of drug regulation.

    Over time, and in fact as early as 1999,

    the Food & Drug Administration asked sunscreen companies

    to do these regulatory studies but for various reasons

    they have not been able to see that data.

    What are alternatives to sunscreen,

    or sort of ways of supplementing the sun blocking

    effects of sunscreen?

    Right now, there are sunscreens that we know are safe

    and these are the mineral sunscreens that we

    talked about earlier and those are not in question at all

    and those have been tested.

    If people are choosing between chemical sunscreen

    and mineral based sunscreen,

    is there a cost difference?

    There's no cost difference.

    Are they as effective as one another?

    Well, as far as we know they're as effective.

    One of the things that we, as dermatologists,

    are still trying to determine is what is the

    effective dosage of sunscreen?

    I think common sense would say you wanna put it on,

    and we all know it rubs off when we go swimming,

    or when we towel off or when we sweat.

    It still needs to be determined whether or not

    there's a particular dose of mineral or chemical sunscreen

    that is ideal for the prevention of

    skin cancer and melanoma.

    I think one important piece of this study,

    the research article that we're talking about,

    is that this was idealized conditions.

    So the subjects put the sunscreen on and they sat

    in climate controlled environments,

    so they weren't swimming, they weren't sweating

    or even moving around and they weren't actually

    exposed to the sun and so we don't know what,

    in the real world and under real world conditions,

    what those systemic absorptions are like,

    whether they're the same or not to those found

    in this particular study.

    Speaking of real world conditions and the

    question of dosage,

    there's also this factor of behavioral psychology, right?

    Which is, I know there have been some studies

    that look at people who apply sunscreen and think

    that they're getting the protection in some cases,

    and in some cases get burned worse than people

    who are taking protective measures to protect themselves

    knowing that they haven't applied sunscreen.

    So that's, the real world scenario is a really big variable

    that is hard to account for.

    It is and this has actually been shown in studies.

    People put on about half the amount of sunscreen

    as on a sunscreen label, so that's one important

    real world condition as well but we don't actually know

    whether those real world conditions,

    for example, if you just use less sunscreen

    to get less absorption, whether that would impact

    its safety and effectiveness as a tool to prevent

    skin cancer and melanoma.

    What are the next steps for the

    Food & Drug Administration?

    So in February of this year there was a proposal

    put forth that the Food & Drug Administration will

    really mandate that sunscreen companies provide

    the safety testing.

    So the onus is really on the sunscreen companies,

    not on the Food & Drug Administration.

    What are the next steps for sunscreen manufacturers.

    Yeah, so the sunscreen manufacturers are now

    going to be required to test their products

    for safety testing.

    So that safety testing will begin with

    systemic absorption, so looking to see if it gets

    absorbed into the sunscreen,

    and that's for 12 ingredients in this particular FD ruling,

    and if there is evidence of systemic absorption

    past the, or above, the safety threshold

    that the Food & Drug Administration has for all,

    it's common to all medications,

    then it will trigger additional safety testing,

    which included toxicity studies, cancer risk and

    effects on things like hormones and reproduction.

    How soon could this realistically affect what

    people see on the shelves at their local

    pharmacy or supermarket?

    Well, in theory, if the sunscreen companies

    don't provide this data by November of 2019,

    in theory these products could be pulled from the market.

    I think we would all agree this would be

    a very extreme measure given that we don't actually have

    any data right now that they're unsafe.

    However, this is sort of what is being set up

    by this current proposed ruling.

    That being said, I think companies also need time

    to do the studies and likely there will be an opportunity

    for them to request extensions as long as they're

    working on doing the testing that's been requested.

    What is sort of the one big takeaway people should

    have from this study?

    It's really important for people to know that

    it's really essential for them to protect their skin

    from the sun and there's lots of different ways to do that.

    And sunscreen is an important piece of that

    so people should still wear sunscreen.

    If they have concerns about the chemicals that

    were in this particular study,

    they can choose things that we know are safe,

    including the mineral sunscreens that we

    talked about earlier.

    But the real key here is that we don't know,

    especially from this study,

    that the four sunscreen ingredients that were studied

    are actually dangerous, we don't know that yet.

    And we do know that sun exposure is dangerous.

    We absolutely know that.

    That is not in question.

    Well, thank you very much for joining us today.

    It sounds like sunscreen is still a good idea.

    If you don't wanna use sunscreens that have these

    sort of chemicals in them,

    the effects of which are kind of unclear,

    you have other options and people can, of course,

    stay out of the sun and wear protective clothing too.

    Absolutely.

    Up Next
    bet365娱乐