In Search of Natural Light

11 Oct In Search of Natural Light

Research indicates LED day-time health benefit, but possible nighttime risk

It’s not yet cost-effective for residential use. But Light Emitting Diode (LED) technology is improving every day and ultimately slated to replace most other artificial light forms. Will it yield, I ask hopefully, a more natural and healthful light than the compact fluorescent light bulbs I am using?

“You seek the Holy Grail,” answers Phil Richards, a senior instructor with The Juno Lighting Group. “And what you are asking about is an amazingly complex topic, currently being addressed by the American Medical Association (AMA) and medical societies in the European Union as well.”

The AMA issued an alert in June because of research that shows certain types of nighttime lighting suppress our natural circadian rhythm, and shift-workers have been shown to have an increased incidence of breast cancer and other medical conditions.  Additional research published in April suggests a possible reason: The blue light — in LED and all non-incandescent light forms in use today — affects non-visual, blue-sensitive photoreceptors in the retina, which in turn suppresses melatonin production.

Melatonin suppression , which spurs serotonin secretion, is needed during the daytime. This has many companies promoting blue light, and one has even developed a window glass that permits maximum infiltration of blue light rays.

Visually, LEDs and other light forms can offer beautiful color renderings that appear very natural even though they are made with carefully manipulated spikes of colored energy and are not full-spectrum lighting that we get from the sun, or soon-to-be-obsolete incandescent bulbs, says Richards, who recently gave an LED presentation to the AIA Cincinnati Chapter on behalf of Richards Electric Supply Co.

“All the non-incandescent or artificial light sources we use today, even those with a warm appearance, have a very strong blue component,” Richards says. “In fluorescent and metal halide, the mercury arc is very blue, and the native color of the white LED is a very rich, saturated, monochromatic blue. But LED is not full-spectrum lighting since it contains no infrared or ultraviolet energy.”

From a purely visual and emotional perspective, the low cost dimability of LED, and Juno Lighting Group’s Warm-Dim product, will feel more natural than non-dimming metal halide and fluorescent lighting, Richards says.

“But to replicate the continuously changing nature of daylight, not just in appearance, but in spectral composition, is presently a goal, not a reality,” he says.

LED lighting visually is more natural, and better from an interior design standpoint. As most people know, a paint color chosen during the day in natural light but put it in a room that has incandescent or fluorescent lights, will look much different, she says.

The nice thing about the white LED’s is that any color chosen in sunlight or natural light, will look the same in the new white LED’s. The room will feel cleaner, crisper and brighter.

But even the “white LEDs” contain blue.

“Although a logical link may exist between short-wave blue light at night and diseases, it is important to point out that an empirical, scientific link between light at night of a given amount and spectral composition, and an increased risk of disease in humans has not yet been made,” according to the Lighting Research Center’s website. “Similarly, it is too soon to claim that light at night has no impact on health.”

Research published by The University of Surrey, UK, focused on blue-sensitive photoreceptors in the human retina of the eye that controls the brain’s pineal gland.  The blue-sensitive photoreceptors in the retina – a relatively new discovery — are non-visual and part of a light-sensitive photoreceptor group called Intrinsically Photosensitive Retinal Ganglion Cells (IPRGCs).

After these cells were exposed to blue light at nighttime, the pineal gland suppressed melatonin production. Previous evidence has shown that natural melatonin production is needed for proper sleep in addition to the prevention of certain cancers and Type 2 Diabetes.

Still, solutions are hopefully looming. Research also has shown that negative effects of evening light can be reduced by reducing light intensity or using yellow light with minimal blue content.©