Please Explain: How Sun Affects Skin

Friday, July 23, 2010

On today’s edition of Please Explain, Dr. Monica Halem, Clinical Associate Professor of Dermatology at Columbia University New York Presbyterian Hospital, discusses what happens to our skin when it’s exposed to too much sun, and how UV rays can cause irreversible damage.


Dr. Monica Halem

Comments [55]

lere from Scotland

Yes that sounds plausible - but it's wrong. The huge state of the art July 2010 study Common genetic determinants of vitamin D insufficiency: a genome-wide association study found that none of the genes they identified are linked with skin pigmentation.

Confirmation of that interpretation in an article Here :- ” the accompanying (Lancet) editorial points out, it is somewhat surprising that none of the genes identified are linked with skin pigmentation”

A systematic review of the association between common single nucleotide polymorphisms and 25-hydroxyvitamin D concentrations
"We speculate that recently identified U-shaped relationships between 25OHD concentrations and disease outcomes (i.e. increased risk at both high and low concentrations) may reflect a mixture of genotype-defined subgroups."

'Genetics to Blame for Vitamin D Deficiency?'
"Researchers conducted a genome-wide association study (Common genetic determinants of vitamin D insufficiency: a genome-wide association study) that involved almost 34,000 people of European descent from 15 different studies. They used radioimmunoassay and mass spectrometry to determine vitamin D concentrations and found that variants at three genetic sites, or "loci," were significantly associated with vitamin D concentrations. The presence of harmful alleles at three "loci" more than doubled the risk of Vitamin D insufficiency."

Maybe non-whites are the ones who benefit from doubling their vitamin D levels ? Nope - Vitamin D, Adiposity, and Calcified Atherosclerotic Plaque in African-Americans "positive associations exist between 25-hydroxyvitamin D and aorta and carotid artery CP in African-Americans"

Many people are naturally low in vitamin D, forcing vitamin D levels up by taking supplements can only do harm. If you think you can improve yor health by conforming to the advice of Holick or - God forbid - that of Hollis, Cannel & Co at the vitamin D 'Council' who recommend (>50ng/ml) then you are in for an unpleasant surprise.

Vitamin D and homeostasis

Mad dogs and ....

Jul. 30 2010 02:14 PM
Pavel Gurvich

I was the one who asked the question about vitamin D. Doctor answered saying that she thinks it is impossible to distinct supplementation vitamin D from the one generated by Sun rays.

This was a surprising answer. If you look in the blood test provided by Quest Diagnostic you will see two vitamin Ds one from Sun and another from supplementation. Despite the fact that I take multivitamins and vitamin D from Orange Juice and Milk my vitamin D is practically zero. The same results for my wife, my daughter, my son in law and many other people I know.
This means that somebody is lying. Whether it is Doctor or Quest Diagnostics. I set an appointment with my Doctor to find the truth.

Jul. 23 2010 04:11 PM
Matthew from NYC

This was an unfortunately lopsided opinion piece instead of science. You really need to interview somebody who has a more balanced understanding of the relevant research and understands the benefits of sunlight.

Jul. 23 2010 02:16 PM
Andrea from White Plains

Could you please explain what PABA is and how PABA free sunscreens works differently than sunscreens with PABA?

Jul. 23 2010 01:58 PM
Amy from Manhattan

And it's spelled vitiligo.

Jul. 23 2010 01:58 PM
Deborah Rosenberg from NYC

Can you comment on Efudex. A drug that I was told can reverse the damage already done by the sun.

Jul. 23 2010 01:57 PM
Joseph Cavalieri from east village new york

How about makeup-
are there problems with sunscreen protection if you apply makeup over it?

Jul. 23 2010 01:57 PM
Ani from Brooklyn

Is there any hope that a safe and effective oral medication to prevent sunburn and sun damage will be developed?

Jul. 23 2010 01:57 PM
Emma from New Jersey

I've always found that getting a tan clears up my eczema, is there a particular reason for that?

Jul. 23 2010 01:57 PM
Carol from Westchester

Regarding "Waterproof and Sweatproof Sunblock" Just how waterproof and sweatproof are they? I play sports outdoors use an SPF OF 70 or higher and sweat a lot and the sunblock seems to melt away very quickly. (I think they also make me sweat more.) Any recommendations?

Jul. 23 2010 01:56 PM
soulmariposa from Brooklyn

I would love to hear a show for people of color and sun damage. Most of these stories seem like they are for white people with a asterisk that says "Oh and you too Black people". The degree of the protection needed is different for people of color and requires more attention than it gets.

I am not someone who thinks Black folks shouldnt do anything. I've gotten sunstroke before and I know its serious. But as a dark skinned Black woman I don't buy that I should be as afraid as White folks.

Jul. 23 2010 01:55 PM
Amyre Loomis from Brooklyn, NY

Please comment on Melasma and how the sun affects it, as well as how to best combat and treat this seemingly uncontrollable condition for me. I and 45, no children yet, and a fair complected Black women. Thanks. (Using bleaching creams to treat.)

Jul. 23 2010 01:55 PM
Robert Plautz from New York

Regarding "reversing" sun damage, what does Dr. Halem think about photo dynamic therapy effect on "reversing" sun damage? Or does photo dynamic therapy only have a cosmetic effect on sun damage?

Jul. 23 2010 01:55 PM
JAY from ct

What SPF do African Americans need?

Jul. 23 2010 01:53 PM
michelle from brooklyn, ny

can you please comment on the dangers from chemical sunscreens?

Jul. 23 2010 01:49 PM
Brian from Astoria, NY

She sounds like a shill for the sunscreen industry. What is the relationship between the current dermatology industry and the sunscreen industry?

Jul. 23 2010 01:48 PM
Alex from Manhattan

This guest's position seems extreme and phobic: the ideal is zero exposure to the sun's rays, and we should do everything we can to achieve that ideal.

Why do I have the feeling that another expert might take a different or at least a more moderate position?

Jul. 23 2010 01:47 PM
Katie from NYC

I think the biggest reason people don't wear sunscreen is the slimy, heavy feel. What can we do about this?

Jul. 23 2010 01:47 PM
Jacky from Carroll Gardens, BK

are there long-term negative effects from sunblock? What kind of chemicals are actually in block?

Jul. 23 2010 01:46 PM

What about the toxins in sunscreens?? Is it really safe to be putting so much sunscreen on every day and letting it accumulate over a lifetime?

Are certain ingredients safer than others?

Jul. 23 2010 01:46 PM
Brian from Astoria, NY

She sounds like a shill for the sunscreen industry. What is the relationship between the current dermatology industry and the sunscreen industry?

Jul. 23 2010 01:46 PM
Katie from Brooklyn

I work in a studio with really large windows. I always thought that UV rays didn't pass through glass but some days I feel like my skin is burning. Do I need to wear sunblock even though I am sitting inside a room with closed windows?

Jul. 23 2010 01:43 PM
Kathy from central New Jersey

Thank you for this "Please Explain"! My eyes and skin are very sensitive to chemical sunscreens, and even a little bit to mineral sunscreens. Fortunately I work at home, so I don't have to wear sunscreen every day. I confess that sometimes I do not apply sunscreen when I go out in the car to run an errand or go to the gym, i.e., times when my only exposure is through the car window and walking to and from the parking lot and my destination. How much additional risk am I incurring when I do this? (Naturally, when I exercise outside or will otherwise be outdoors more than just described, I slather it on.)

Jul. 23 2010 01:43 PM
Andrea Holmes from madrid, spain

isn't this race specific? i remember hearing that black people don't get enough vitamin d. plus, those of us with very dark skin have more natural protection from the sun. what's spf is best for us? and is getting enough vitamin d an issue for us?

Jul. 23 2010 01:42 PM
donna from Montclair

I have seen studies that suggest there may be an estrogenic effect when sunscreens interact with other chemicals. Can you comment and suggest natural alternatives.

Also, this is a huge industry, are some of the products available in other countries being kept out by the pharma industry?

Jul. 23 2010 01:42 PM
Jean Freely from NYC

Does one event of sunburn on my shoulders from a recent Bahamas trip give me a significant risk for cancer if I am otherwise careful, don't sunbathe, and don't get burns?

Jul. 23 2010 01:42 PM

I recently red that oxybenzone is a hormone-disrupting compound found in most sunscreens. The chemical penetrates the skin and enters the bloodstream: biomonitoring surveys conducted by the federal Centers for Disease Control and Prevention have detected oxybenzone in the bodies of 97 percent of Americans tested. Any comments or safer and effective ingredients to look for?

Jul. 23 2010 01:42 PM
Eric from City Island

What about SPF clothing? It seems like a bit of a scam to me. I spend a good deal of the summer on a boat and generally wear a light weight cotton shirt and wide brimmed hat. I never burn through the shirt but can get a burn on my hands or other un-covered areas.

Speaking of which... if one burns on a few exposed places (which I always forget to put lotion on) but only a few, does that increase one's chances of skin cancer?

Jul. 23 2010 01:41 PM
john Allmond from Bklyn

Did the doctor really just suggest sunscreen, every day? Winter, Summer, cloudy or sunny?

Jul. 23 2010 01:41 PM

This is the stuff. Does it work?
Rit SUnguard

And for sunburn: Sourcream, toped with a washcloth

Jul. 23 2010 01:41 PM
betsy from manhatten

I use Neutragina "build-a-tan." I know I'm dying my skin to get a tan - is this dangerous?

Jul. 23 2010 01:40 PM

Is sunscreen safe for pregnant women? Is there a "better" or "worse" kind if you're pregnant?

Jul. 23 2010 01:39 PM
Sara from upper west side

Could you explain "polymorphous light eruption" and how to avoid triggering this condition?

Jul. 23 2010 01:38 PM
PL Hayes from Aberystwyth

Prof. Sam Shuster has claimed (in the British Medical Journal and elsewhere) that tanning is in fact good for us and speaks of the “melanoma scare”. Has Dr Halem heard of this (retired?) dermatologist and his contrarian views?

Jul. 23 2010 01:38 PM
Valerie from Cold Spring, NY

Antibiotics, apparently, cause increased sun sensitivity. What is the mechanism for this? This is a serious concern North of the City where Lyme's disease is prevalent, and many children have to take 3 weeks of an antibiotic in the summer, when they spend a great deal of time outside.

Jul. 23 2010 01:38 PM

Is sunscreen safe for pregnant women? Is there a "better" or "worse" kind if you're pregnant?

Jul. 23 2010 01:38 PM

Do you need sunscreen even if it´s cloudy?

Jul. 23 2010 01:37 PM
Rebecca from Saranac Lake NY

You mentioned covering your eye area with sunscreen, but all sunscreens caution to keep away from your eyes.

Jul. 23 2010 01:37 PM
Jon from Brooklyn, NY

I've tried a number of different brands of sunscreens, but if I use any of them on a daily basis, my skin gets irritated. Do you have any recommendations for sunscreens for sensitive skin (particularly natural sunscreens)?

Jul. 23 2010 01:37 PM
Natasha from Brooklyn

My cousin was diagnosed with Acute Myeloid
Lukemia at 47. Sadly, she passed within 2 months. I remember that as a teenager she spent hours sunbathing, and I mean 3-7 hours a day, nearly every day, in the summer. Could this have contributed to her illness?

Jul. 23 2010 01:37 PM

If I put on sunscreen 15 min. before leaving the house, as recommended, I sweat it off in those 15 minutes!

Any suggestions?

And what about
1) washing your clothes in the stuff that promises UV protection?

2) anti-glare coating for window -- do they work?

Jul. 23 2010 01:36 PM
Ann from NY

Is it possible to get rid of or undo freckles or sunspots?

Jul. 23 2010 01:36 PM
abdul from Brooklyn

are certain skin types, such as darker/African Americans less prone to harmful effects from UV rays?

Jul. 23 2010 01:36 PM
Annie from Brooklyn

Is anyone working on a sunblock pill that would provide the same degree of protection as SPF15+ cream? What are the challenges with this?

Jul. 23 2010 01:36 PM
Alexander Nagel from Manhattan

Do sunscreens prevent us from receiving vitamin D?

Is it true that some sunscreens are themselves damaging to the skin?

Jul. 23 2010 01:35 PM
mary lou minard from Great Neck, NY

Don't we need some sun exposure without sunscreen in order to develop Vitamin D in a natural way? I have read 20 minutes without sunscreen, then apply.

Jul. 23 2010 01:35 PM
Faith from Rockland County, NY

Three years ago, I suddenly started to get red bumps that seemed to be related to exposure to the sun. That had never happened to me before, but now occurs regularly each summer. What is it about?

Jul. 23 2010 01:35 PM
Ellen from New Jersey

How do we balance the need for Vitamin D with protecting ourselves from sun damage?

Jul. 23 2010 01:35 PM
Ash in Chelsea

You have a lot of impressive guests on your show. Then, you have some who are just dazzling. Dr. Halen is dazzling.

Jul. 23 2010 01:35 PM
john P Pittman

Doesn't exposure to sun trigger the production of vitamin D in the skin? Can one get enough of that without damaging one's skin?

Jul. 23 2010 01:32 PM

I get brown spots and freckles on my hands, even though I apply a lot of 70 spf sun screen. What is the sunscreen really doing?

Jul. 23 2010 01:31 PM

I've read that a chemical that protects against UV rays is available in European sunscreens but not here in the US. Can you explain why we aren't being protected here, and are these better sunscreens available in Canada?

Jul. 23 2010 01:28 PM

Leonard, please ask your guest if the over-the-counter sun screens sold in drugstores even possess the necessary ingredients that protect against UVA and UVB rays.

Jul. 23 2010 01:23 PM
Amy from Brooklyn

Can either kind of UV light pass through window glass? If so, would it still be strong enough to cause a burn?

Jul. 23 2010 09:27 AM
Sandy from Newport Beach, CA

Even though I slather sunscreen on, my skin still turns brown. Does that mean my sunscreen is not working? (I use the kind with zinc and titanium dioxide.) Does the browning mean damage to the skin?

Jul. 22 2010 05:23 PM

Leave a Comment

Email addresses are required but never displayed.

Get the WNYC Morning Brief in your inbox.
We'll send you our top 5 stories every day, plus breaking news and weather.