Read more: https://www.newscientist.com/article/2582914-the-shock-revelation-that-light-bulbs-are-wrecking-your-metabolism/

The shock revelation that light bulbs are wrecking your metabolism
Since the 2000s, our light exposure has changed drastically as we make our buildings more energy-efficient. Now, we’re discovering how this may mess with our mitochondria, contributing to diabetes, dementia and more

Sunlight has long been understood to be critical to life on Earth. But the fact that light is also used to oil the wheels of metabolism is only just, er, coming to light. Long wavelengths, which come from red and infrared (IR) light, are particularly beneficial for creating energy, and are readily available from sources including sunlight and incandescent bulbs.

But changes in lighting intended to help save energy have inadvertently deprived us from this crucial supply. The irony is that just as we have discovered the benefit of red light, we are unint

A neuroscientist is warning that our dependence on LED lighting could become an “asbestos-level” public-health problem.

The concern isn’t simply that LEDs produce blue light. It’s what most conventional LEDs leave out.

Natural sunlight contains a broad spectrum of wavelengths, including red and near-infrared light. Standard LED lighting, by contrast, is concentrated largely within the visible spectrum and produces very little light beyond roughly 700 nanometers.

That difference could matter to our mitochondria — the microscopic structures responsible for producing cellular energy.

Research led by University College London scientist Glen Jeffery has found that mitochondria respond differently to different wavelengths of light. Shorter blue wavelengths around 420–450 nm can suppress mitochondrial respiration in experimental models, while red and near-infrared wavelengths around 670–900 nm have been associated with increased mitochondrial activity.

In a 2026 study published in Scientific Reports, researchers supplemented an LED-lit workplace with broader-spectrum lighting extending into the infrared for two weeks. Participants subsequently showed significant improvements in measures of color-contrast vision, with effects persisting for weeks after the supplemental lighting was removed.

But that comparison should not be mistaken for an established scientific conclusion. The research does not prove that ordinary LED bulbs cause an asbestos-like burden of disease, nor does it establish that people living under LEDs are literally being “starved” of infrared light. The 2026 study primarily examined visual performance, while broader effects on metabolism, aging and disease remain areas of active research.

Still, the findings raise a fascinating question about modern life: we engineered indoor lighting around what our eyes can see and how little electricity it consumes — but did we overlook wavelengths that the rest of our biology may respond to?

Source: Barrett, E. M. & Jeffery, G. (2026). LED lighting (350–650 nm) undermines human visual performance unless supplemented by wider spectra (400–1500 nm+) like daylight. Scientific Reports, 16, 3061.

LED lighting may be leaving our cells short on red and near-infrared light

Modern LED bulbs are highly energy-efficient, but researchers warn that many have a narrower spectrum than natural sunlight and incandescent lighting. This raises questions about how long-term exposure to blue-heavy indoor lighting may affect mitochondrial function and human health.

Neuroscientist Glen Jeffery argues that mitochondria may benefit from longer red and near-infrared wavelengths, which are largely absent from conventional LEDs. He links this potential “infrared starvation” to concerns involving metabolism, vision, and blood-sugar regulation, although the strength of these health claims remains debated.

Researchers suggest using broader-spectrum lighting and getting regular exposure to natural morning sunlight as practical ways to increase exposure to red and near-infrared wavelengths. However, calling LED lighting an “asbestos-level” crisis is a strong comparison that should be treated as a warning or hypothesis rather than an established medical fact.

Source:
Scientific Reports by Jeffery, G. – LED lighting 350-650nm vs 400-1500nm+ daylight

A New Scientist investigation published August 10, 2026, drawing on research from University College London Professor Glen Jeffery and a peer-reviewed study in Scientific Reports, has confirmed that standard LED lighting is systematically undermining human metabolic health. The core problem is spectral imbalance: LEDs emit heavy blue-wavelength light between 420 and 450 nanometres while stripping out the red and near-infrared wavelengths that mitochondria depend on to generate energy, regulate blood sugar, and control the pace of cellular aging. The result is slowed metabolism, increased insulin resistance, elevated blood glucose, reduced oxygen consumption, and impaired vision, all measurable consequences of what Jeffery calls “infrared starvation.”

When Jeffery’s team replaced LEDs with incandescent bulbs in a windowless workspace at UCL, visual function improved significantly across all participants. A separate experiment found that brief exposure to deep red light lowered blood glucose levels by stimulating mitochondria to consume more glucose and oxygen. Jeffery has called the situation an asbestos-level public health crisis. Simple mitigations include spending more time in natural daylight, especially before noon, using incandescent or full-spectrum bulbs indoors, and limiting LED screen exposure in the hours before sleep.

Sources: New Scientist, NewsNation, Scientific Reports, University College London, May to August 2026

Lue tiivistelmä
Suomessa monet katuvalot ovat vaihtuneet oransseista valkoisiksi.

Valkoinen valo voi vaikuttaa ihmisen vuorokausirytmiin ja nukahtamiseen enemmän kuin oranssi.

Valkoiset led-valot voivat myös häikäistä enemmän kuin vanhat oranssit katuvalot.

”Minun ei tee edes mieli mennä ulos.”

Katulamppujen valkoinen valo ärsyttää lietolaista Elina Alipirjelää, 41.

”Tuo valo on ahdistavaa ja häiritsevää.”

Alipirjelä on seurannut, miten lähiympäristön lämpimän oranssit katuvalot ovat vaihtuneet valkoisiin.

Katuvalojen väri ei ole Alipirjelälle vain fiiliskysymys. Hänestä valkeat katuvalot häikäisevät märältä asfaltilla enemmän kuin oranssit ja ovat liikenneturvallisuusriski.

”Mielestäni näkyvyys on huonompi.”

Valon värillä on tutkitusti vaikutuksia ihmiseen.

Kirkas valo illalla voi lykätä nukahtamista, ja valkoisen valon piristävä vaikutus on yleensä vahvempi kuin oranssin, kertoo Turun yliopiston psykologian erikoistutkija Nils Sandman.

Valkoiset katuvalot voivat hänen arvionsa mukaan vaikuttaa nukahtamiseen, jos niiden valossa on viettänyt aikaa juuri ennen kuin olisi tarkoitus mennä nukkumaan.

”Todennäköisesti suurempi vaikutus nukkumiseen on kuitenkin illalla kotona vallitsevalla valaistuksella.”

Valon väri vaikuttaa myös näkemiseen.

Valkoisen valon katselemisen jälkeen silmällä kestää kauemmin tottua pimeään kuin oranssin valon katselemisen jälkeen. Sinertävän valkoinen kova valo myös häikäisee enemmän kuin oranssi, kertoo Tampereen yliopiston emeritusprofessori Hannu Uusitalo.

Sinertävää kovaa valoa on Uusitalon mukaan etenkin ”vanhanaikaisissa” valkoisissa ledeissä.

Oranssia valoa luovissa suurpainenatriumlampuissakin on ongelmansa. Niiden valossa on vaikea erottaa värejä.

”Käytännössä miltei kaikki näyttää kellertävän oranssilta”, sanoo Uusitalo.

Valon väri vaikuttaa myös ihmisten tunteisiin

Personally I still have my nocturne and wildfire units in inventory and are using them when the need arises. Wildfire is still in the game and they have LED units available. I’ve never had a shootout with a 400 though.

I’ve been meaning to check out the Antari DarkFX 2000. IP65. 35° beam angle. DMX. Looks promising.

The one thing to be careful with is some cheaper LED fixtures may not produce true UV and may have a bit of visible light to the output.

The Elation Prisma series of fixtures are pretty nice.

Otherwise nothing beats a Wildfire. They’re still around.

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