Can LED bulbs give you diabetes? UCL neuroscientist warns modern lighting may damage mitochondria and affect metabolism

LED bulbs are ubiquitous. Whether at home or in the office, LED lighting has become a part of everyday life. We rarely think twice before installing one. They are also more energy-efficient than many traditional lighting sources.

But are LED bulbs safe for our health?

Some researchers have raised concerns that prolonged exposure to LED-dominated lighting environments could affect metabolism and other aspects of health. One researcher has gone as far as claiming that LED lighting could increase the risk of diabetes and other metabolic disorders.


Glen Jeffery, a professor of neuroscience at University College London, has claimed that LED bulbs can damage mitochondria and potentially contribute to metabolic problems. He has compared the health implications of LED lighting to those of asbestos.

“LED lighting is damaging mitochondria and therefore there is no question you’re damaging systemic health,” Jeffery told The European. “This is a clear and present public health emergency and we need to take action.”

Mitochondria play an important role in producing energy and regulating metabolism. Mitochondrial dysfunction has also been associated with ageing and several diseases.

Jeffery believes the effects could be driven by changes in signalling throughout the body.

“The mitochondria there send messages around in your blood,” he explained. “It changes the blood signaling through what are called cytokine profiles. The mitochondria form a community and signals are sent throughout your body.”

What does the research say?

Jeffery, along with Edward M. Barrett, also conducted research at University College London involving 22 healthy adults aged between 23 and 65.

Participants were exposed for two weeks to either broader-spectrum tungsten lighting or standard LED lighting.

Those exposed to the broader-spectrum lighting showed improvements in colour-contrast vision, while the LED group did not.

The researchers' argument centres partly on the composition of LED light.

LED bulbs emit a relatively high proportion of short-wavelength blue light, with some of it falling between 420 and 450 nanometres (nm). Blue light, however, is only one part of the visible spectrum. At the opposite end are longer-wavelength red light and infrared radiation, which lies beyond the range visible to the human eye.

Sunlight contains the full visible spectrum and also extends into infrared wavelengths. Some traditional artificial light sources, including incandescent and halogen bulbs, emit longer wavelengths as well.

Conventional LEDs, by contrast, emit little or no infrared light.

Jeffery and his colleagues argue that this absence of infrared light may be important. Their concern is not simply blue light itself, but the lack of infrared exposure in environments where people spend much of their time indoors.

“The absence of infrared light in the artificial lighting environment decreases the efficiency of your mitochondria,” Fosbury said. “You’re less able to metabolise properly, over a timescale of days, weeks, months. This is what’s happening to the urban population today, all living indoors. It’s blamed on the blue light from LEDs, but people indoors are in infrared darkness.”

From this perspective, the problem with LED lighting is not necessarily that it adds something harmful, but that it removes a component — near-infrared light — that may have biological effects.

While talking to The European, former European Space Agency and Hubble scientist Fosbury compared the proposed phenomenon to a modern form of scurvy, arguing that it develops over a similar timescale to the disease caused by vitamin C deficiency.

Jeffery's proposed solution is to increase people's exposure to near-infrared light. He has suggested using an incandescent or halogen bulb alongside LED lighting to introduce broader-spectrum light into indoor environments.

However, these claims remain a subject of scientific debate and should not be interpreted as evidence that LED bulbs directly cause diabetes.

What have studies on LED lighting found?

Research in animals has raised some concerns about the biological effects of LED exposure.

One study conducted on mice found that exposure to two short wavelengths generated by LEDs had significant detrimental effects on the animals.

Another study found that blue-enriched daytime LED lighting altered metabolic activity and signalling pathways in the liver and skeletal muscle of mice.

However, findings from animal studies cannot automatically be applied to humans. The exposure levels, duration and experimental conditions can also differ substantially from normal household or workplace lighting.

The European Commission's Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has stated that there is no evidence of direct adverse health effects from LEDs under normal use in the general healthy population.

“All light sources affect the circadian rhythms, but more research is needed to ascertain the specific impact of LED lights on the sleep/wake cycle, and also to determine if disturbances to the circadian system lead to adverse health effects,” SCHEER says.

The committee also notes that some studies involving LEDs and cells or animals have reported negative effects, particularly in vulnerable groups. However, it says these experiments used exposure conditions that were far greater than those associated with normal use and would be difficult to replicate in humans.

So, can LED bulbs give you diabetes?

There is currently no established evidence that using LED bulbs causes diabetes.

Some researchers, including Jeffery, have proposed that the lack of infrared light and the characteristics of LED lighting could affect mitochondrial function and metabolism. Studies in mice have also reported changes in metabolic activity following certain forms of LED exposure.

But that is different from demonstrating that LED bulbs cause diabetes in humans.

For now, the strongest conclusion is that the biological effects of different types of artificial light — particularly their effects on circadian rhythms, metabolism and long-term health — warrant further research. The available evidence does not establish LED lighting as a cause of diabetes.