Featured Research

from universities, journals, and other organizations

Shining light on damage from daily sun exposure: Better sunscreens needed

Date:
December 4, 2013
Source:
University of Michigan Health System
Summary:
A low level of daily exposure to a common component of sunlight can cause skin damage at the molecular level after just a few days, new research shows. The findings highlight the need for better sunscreens to protect against these damaging rays.

The new findings suggest a need for new sunscreen ingredients that can protect against UVA1 rays. Currently, only zinc oxide and avobenzone are approved by the U.S. Food and Drug Administration as sunscreen ingredients capable of blocking UVA1. Window glass, and most clothing, also don’t necessarily filter out all UVA1.
Credit: © miiko / Fotolia

A low level of daily exposure to a common component of sunlight can cause skin damage at the molecular level after just a few days, new University of Michigan Medical School research shows.

Related Articles


The research highlights the need for better sunscreens to protect against these damaging rays, and prevent the process that can cause skin to look old, wrinkled and sagging prematurely.

In a new paper published online in JAMA Dermatology, the researchers show that damage starts after just two daily exposures to a low amount of ultraviolet A1, or UVA1, light – which makes up most of the UV light we are exposed to throughout the day, and tanning bed light too. Very few of the ingredients in sunscreen products effectively protect against UVA1. The damaging process kept going after further daily exposures.

By showing that repeated exposure to the type of UVA1 light that we typically experience on a sunny day causes these damaging processes in the skin, the researchers hope it will lead to the development of new protective ingredients in sunscreens, and more caution about routine sun exposure throughout the day.

The study was done by a team from the U-M Department of Dermatology’s Photobiology and Aging Skin Research Program, and funded by the National Institutes of Health.

The researchers were able to measure the effects of UVA1 at the molecular level using advanced gene expression analysis of skin samples from human volunteers.

The researchers shined a low level of pure UVA1 rays, as might be encountered in daily life, on small areas of 22 volunteers’ buttocks. A day later, they measured changes in skin pigmentation. Then, they took tiny samples of skin, in order to detect which genes had been ‘turned on’ by the light exposure. They repeated this process three more times on each participant.

After just two exposures, UVA1 rays caused skin cells to make molecules that break down the protein called collagen, which makes skin firm, smooth, and youthful in appearance. The UVA1 also caused the skin to darken a little with each exposure, but this tan didn’t protect against further production of the collagen-destroying molecule, called matrix metalloproteinase 1 or MMP1, when the skin was exposed to more doses of UVA1.

“Premature skin aging from UV exposure has gotten a lot of attention in the last 10 years, but most researchers have focused on UVB rays, which cause sunburn,” says first author Frank Wang, M.D. “But there is very little UVB in sunlight, and most UVB exposure is at midday. During the rest of the day it’s mostly UVA, with UVA1 being the majority. UVA1 is also the main component of tanning booth light. So, we wanted to look at whether it can predispose skin to premature aging by simulating repetitive daily exposure. And we found that it can. Furthermore, the mild tanning that occurs does not seem to protect against damage from additional exposures.”

The study exposed the fair-skinned volunteers in a repeat manner to the amount of UVA1 they would receive in about two hours of strong sun exposure. Statistical analysis showed the pattern of MMP1 production increased progressively with repeated exposure in the majority of patients.

A medical dermatologist and assistant professor of dermatology, Wang notes that he often observes the collagen-damaging effects of repetitive sun or tanning booth exposure -- with people in their 20s and 30s coming in for other conditions, but with clear signs of premature aging to their skin.

The U-M researchers, led by senior author and lab director Gary Fisher, Ph.D., the Harry Helfman Professor of Molecular Dermatology and Professor of Dermatology, have previously shown similar changes in skin cells from other types of UV light – including UVB.

However, in contrast with what the researchers had seen with their UVB experiments, the repeated UVA1 exposures didn’t suppress the genes that make the molecules that become collagen.

The bottom line, they say, is that the new findings suggest a need for new sunscreen ingredients that can protect against UVA1 rays. Currently, only zinc oxide and avobenzone are approved by the U.S. Food and Drug Administration as sunscreen ingredients capable of blocking UVA1. Window glass, and most clothing, also don’t necessarily filter out all UVA1.

Because UVA1 light from the sun reaches the surface of the earth whenever it’s light out, the new research suggests that sunscreen with UVA1-blocking components could be useful throughout the day, not just during the peak sunburn hours of late morning to early afternoon, when UVB is most intense.

Though the current study didn’t assess the impact of UVA1 on genetic changes that can lead to skin cancers, other forms of UV are firmly linked to most types of cancerous skin lesions.


Story Source:

The above story is based on materials provided by University of Michigan Health System. Note: Materials may be edited for content and length.


Journal Reference:

  1. Frank Wang, Noah R. Smith, Bao Anh Patrick Tran, Sewon Kang, John J. Voorhees, Gary J. Fisher. Dermal Damage Promoted by Repeated Low-Level UV-A1 Exposure Despite Tanning Response in Human Skin. JAMA Dermatology, 2013; DOI: 10.1001/jamadermatol.2013.8417

Cite This Page:

University of Michigan Health System. "Shining light on damage from daily sun exposure: Better sunscreens needed." ScienceDaily. ScienceDaily, 4 December 2013. <www.sciencedaily.com/releases/2013/12/131204181244.htm>.
University of Michigan Health System. (2013, December 4). Shining light on damage from daily sun exposure: Better sunscreens needed. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/12/131204181244.htm
University of Michigan Health System. "Shining light on damage from daily sun exposure: Better sunscreens needed." ScienceDaily. www.sciencedaily.com/releases/2013/12/131204181244.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins