'White' light suppresses the body's production of melatonin

Exposure to the light of white LED bulbs, it turns out, suppresses melatonin 5 times more than exposure to the light of High Pressure Sodium bulbs that give off an orange-yellow light. "Just as there are regulations and standards for 'classic' pollutants, there should also be regulations and rules for the pollution stemming from artificial light at night," says Prof. Abraham Haim of the University of Haifa.

"White" light bulbs that emit light at shorter wavelengths are greater suppressors of the body's production of than bulbs emitting orange-yellow light, a new international study has revealed.

Melatonin is a compound that adjusts our and is known for its anti-oxidant and anti-cancerous properties.

The study investigated the influence of different types of bulbs on "light pollution" and the suppression of melatonin, with the researchers recommending several steps that should be taken to balance the need to save energy and protecting public health.

"Just as there are regulations and standards for 'classic' pollutants, there should also be regulations and rules for pollution stemming from artificial light at night," says Prof. Abraham Haim, head of the Center for Interdisciplinary Chronobiological Research at the University of Haifa and the Israeli partner in the research.

The study, titled "Limiting the impact of light pollution on human health, environment and stellar visibility" by Fabio Falchi, Pierantonio Cinzano, Christopher D. Elvidge, David M. Keith and Abraham Haim, was recently published in the .

The fact that "white" artificial light (which is actually blue light on the spectrum, emitted at wavelengths of between 440-500 ) suppresses the production of melatonin in the brain's pineal gland is already known. Also known is the fact that suppressing the production of melatonin, which is responsible, among other things, for the regulation of our biological clock, causes behavior disruptions and health problems.

In this study, conducted by astronomers, physicists and biologists from ISTIL- Light Pollution Science and Technology Institute in Italy, the National Geophysical Data Center in Boulder, Colorado, and the University of Haifa, researchers for the first time examined the differences in melatonin suppression in a various types of , primarily those used for outdoor illumination, such as streetlights, road lighting, mall lighting and the like.

In the first, analytical part of the study, the researchers, relying on various data, calculated the wavelength and energy output of bulbs that are generally used for outdoor lighting. Next, they compared that information with existing research regarding melatonin suppression to determine the melatonin suppression level of each bulb type.

Taking into account the necessity for in cities, as well as the importance of energy-saving bulbs, the research team took as a reference point the level of melatonin suppression by a high-pressure sodium (HPS) bulb, a bulb that gives off orange-yellow light and is often used for street and road lighting, and compared the data from the other bulbs to that one.

From this comparison it emerged that the metal halide bulb, which gives off a white light and is used for stadium lighting, among other uses, suppresses melatonin at a rate more than 3 times greater than the HPS bulb, while the light-emitting diode (LED) bulb, which also gives off a , suppresses melatonin at a rate more than 5 times higher than the HPS bulb.

"The current migration from the now widely used sodium lamps to white lamps will increase melatonin suppression in humans and animals," the researchers say.

The researchers make some concrete suggestions that could alter the situation without throwing our world into total darkness, but first and foremost, they assert that it is necessary to understand that artificial light creates "light pollution" that ought to be addressed in the realms of regulation and legislation.

Their first suggestion of course, is to limit the use of "white" light to those instances where it is absolutely necessary. Another suggestion is to adjust lampposts so that their light is not directed beyond the horizon, which would significantly reduce light pollution. They also advise against "over-lighting", using only the amount of light needed for a task, and, of course, to simply turn off lighting when not in use - "Just like we all turn off the light when we leave the room. This is the first and primary way to save energy," the researchers say.

"Most Italian regions have legislations to lower the impact of , but they still lack a regulation on the spectrum emitted by lamps. Unless legislation is updated soon, with the current trend toward sources as white LEDs, which emit a huge amount of blue light, we will enter a period of elevated negative effects of light at night on human health and environment. Lamp manufacturers cannot claim that they don't know about the consequences of artificial light at night," says Dr. Fabio Falchi of ISTIL.

"As a first step in Israel, for example, the Standards Institution of Israel should obligate bulb importers to state clearly on their packaging what wavelengths are produced by each bulb. If indeed influences melatonin production, this is information that needs to be brought to the public's attention, so consumers can decide whether to buy this lighting or not," Prof. Haim says. Provided by University of Haifa

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Sep 12, 2011
Wow! Amazing!

Sep 12, 2011
Now I want to find a study about how fluorescent lighting affects melatonin production... I think it's common knowledge that fluorescent lighting decreases production (through studies of night-shift workers) but 5X decreases for LEDs is pretty amazing

Sep 12, 2011
Not surprising at all. Look into photic driving if you really want to blow your mind.

Sep 12, 2011
Wouldn't suppressing melatonin production in night time drivers help keep them awake while driving at night and therefore be a good thing for highway safety?

Sep 12, 2011
I am somewhat confused. If I understand correctly, melatonin is produced during daylight hours. At night, with no artificial lighting, melatonin production is suppressed, thus regulating our biological clocks. So a light that suppresses melatonin production that is on at night would not interfere with our biological clock at all.

Actually, it's the opposite : melatonine production is stopped by light (the blue range of the spectrum), and is produced at night in darkness.
It not darkness which start melatonine production (rather internal bilological clock), but light does stop it, and doing so, help the biological clock to synchronise with actual day/night rythme.

Sep 12, 2011
I don't see the point in that study.
Ligh spectrum affecting melatonine production is well established.
Sepctrum composition for different light source is also well established.
The argument is that some light bulb would be 'bad' because they stop melatonine and as a consequence shift sleep pattern when used at night.
But using a bulb with less impact on melatonine on the morning would affect sleep patten just the same, not allowing you to 'wake up' properly.

Sound as a study linked with the bulb technologies market share.

Sep 12, 2011
@loboy, I think the concern is that if night-time is when you are up working and the only light you are getting is white LED lighting, then there may be some significant issue with your creation of melatonin.

What I'd like to know is how much yellow light is needed to stay healthy and if there are activities (such as actually being outside in teh sunshine every once in a while) that could mitigate the issue. Or, perhaps there are wavelengths that LEDs could emit that improve melatonin production when white lamps are not needed.

One of the on-going arguments we have here at our production facility is whether to use metal halide or high pressure sodium lighting. I prefer the HPS because it puts out more lumens per watt, lasts longer, doesn't require turning off every 15 days, the ballasts last longer when a bulb burns out and the bulbs are cheaper. Some like MH because it's better for color rendering and they find the white light pleasant.

Sep 12, 2011
I work under HPS lighting for 4 hours a day, started 6 months ago for part-time work, also starting 6 months ago were the best sleep and most vivid dreams I have had in years, I don't know if there's any reason to assume a corrolation, but it is something I noticed.

Sep 12, 2011
I suspect no one at EPA considered this when they banned incandescent bulbs.

Sep 12, 2011
Most domestic CFL bulbs, LED etc already have warm and cool light varieties. So at home we have a choice. However at work or in public you may not. This type of research may change specifiers choices. Perhaps an opportunity for amber tinted night goggles?

Sep 13, 2011
"Wow! Amazing!"

You are right, really amazing what pseudoscience is published here:
What about the color temperature (CCT) of the LED lamp...

In addition the amount of light is relevant. Is the illuminance of street lamps really on a level to have an influence?

Are you sittting under the street light all night long?

What was before HPS lamps were installed?

For your home, chose a warm white LED lamp that has a very similar amount of blue light in the critical range as an incandescent lamp has and the problem is almost solved.

Should we use only use monochromatic HPS lamps in the future?

The niveau of publications here is decreasing dramatically:
This one is written as if we would die immediately if we change to LEDs or is the research sponsored by HPS manufacturers?

Sep 13, 2011
Unlucky explorer, the article is less about the light and more about the effect. You think the effects of light on the human body are pseudoscience ?

Sep 13, 2011
I missed the part where the white LED lighting actually "suppresses" melatonin production. It looks to me like it simply stimulates only 20% of the production that HPS does.

The article states: "The fact that "white" artificial light (which is actually blue light on the spectrum, emitted at wavelengths of between 440-500 nanometers) suppresses the production of melatonin in the brain's pineal gland is already known.", but they don't provide the source for this "fact".

Not stimulating production is far different than actually supressing production.

Sep 13, 2011
I missed the part where the white LED lighting actually "suppresses" melatonin production. It looks to me like it simply stimulates only 20% of the production that HPS does.

The article states: "The fact that "white" artificial light (which is actually blue light on the spectrum, emitted at wavelengths of between 440-500 nanometers) suppresses the production of melatonin in the brain's pineal gland is already known.", but they don't provide the source for this "fact".

Not stimulating production is far different than actually supressing production.

If you want facts you might have to look them up yourself sometimes..

http://www.jneuro...full.pdf html

Sep 14, 2011

No it is not...

I know these effects very well and that for a long time. - Nothing new!

But it is absolutely wrong to blame LEDs in general for this effects!

I only critizise the way the article is written and published:
The authors are bringing out some specific results (claims?) as generalized facts.

This is frivolous pseudoscience to me

Sep 14, 2011
@Isaacsname; I appreciate the link you provided - thanks, it was interesting reading. I read through it twice and I didn't see any mention of "white" light or of any specific frequency that suppresses melatonin production.

However, as you suggested I had to do my own research. What wasn't explained here or in other sites that simply duplicated this same article is that melatonin is produced in darkness. After reading 8 or so articles from varous sources I finally went to Wikipedia to find the information I was missing and that the other articles were not providing: http://en.wikiped...elatonin
"In mammals, melatonin is secreted into the blood by the pineal gland in the brain. Known as the "hormone of darkness" it is secreted in darkness in both day-active (diurnal) and night-active (nocturnal) animals.[8]" Source:
Challet, E. (2007). "Minireview: Entrainment of the Suprachiasmatic Clockwork in Diurnal and Nocturnal Mammals".

Sep 14, 2011
@LuckyExplorer: From what I have read they are specifically discussing the white lights, not other color LEDs. As melatonin is only produced in darkness, when our eyes do not see light, it's not inconcievable that the opposite of darkness (white light from whatever source) suppresses its production. If the article had mentioned that melatonin is only produced when our eyes are in darkness there would not have been misunderstanding on my part.

So, should we wear sunglasses "With the glass so dark thay won't even know your name" (ZZ Top) to not only look cool, but to help keep us healthy also?

Sep 15, 2011
It is true that especially light in the blue range suppresses the production of melatonin. That, doubtlessly, has negative influences on well-being. - But most of these studies cannot exclude other influences on the study.

When I said "...to blame LEDs in general ..." I meant white LEDs too. The spectral distribution of white light is dramatically different depending on the color temperature. High quality warm white LEDs emit less than 1/3 of the cold white LEDs in the critical blue range.

In addition, we have really to distinguish between indoor and outdoor lighting.

In my oppinion outdoor light with a higher amount of the blue spectrum is not really critical. If you are on the way, a higher arousal is beneficial, and you are not exposed to that light continousely.

For night workers it is a completely other issue. Having that influence day by day is critical, of course. - But is night work healthful? It is unnatural and there are much more negative effects than light.

Sep 15, 2011
I agree with you about night-time work not being healthy. I worked 3rd shift for 4-5 years and 2nd shift for about 3 years. While on 3rd shift I had indigestion problems and it was more difficult to think due to lack of good sleep.

When I was in the US Navy our submarine ran on an 18-hour cycle, with 6 hours on duty and 12 hours off as the normal patrol work rotation. Good thing I was young then, I never really got used to it. What I would end up doing is working on duty 6 hours, stay up and study for 12 hours, work on-duty another 6 hours then crash for 10-12 hours. Rinse and repeat. Fortunately there was a lot to learn on a submarine and before I left as a Missile Technician I was also cross trained and qualified as a Torpedoman, Fire Control Technician, Navagational Electronics Tech and as a Sonarman. When I left after 8 patrols and a DASO I was training as a Machinest Mate and a bit as a Radioman (but my security clearance wasn't high enough for the crypto).

Sep 15, 2011
@ Steve, no problem. It's actually the suprachiasmatic nucleus , not the pineal gland that regulates the process. OPN4( Melanopsin ) is supposedly the most well studied opsin as of yet, so finding research pertaining to it is likely. I agree the article coulod have been more in-depth, I had to go read for a few hours about the whole process.

Sep 19, 2011
Yes, white light will keep you awake. But you know what? So will staring at a TV or a monitor! I worked this out for a student paper I wrote: Melatonin suppression caused by staring at your average brightness LCD is only about 10% lower than the maximum of ~73%. In fact, the scale is logarithmic, so let's not fool ourselves: if we stay up and look at bright things, our circadian rhythm -is- going to get messed up. On the other hand, if you want to stay awake later, get some blue lights and you're set. Obviously light isn't the only thing to influence the circadian rhythm, but it definitely has an impact. If you want to get to sleep, well, close your eyes.

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