Type 2 diabetes—when insulin resistance in the body leads to elevated blood sugar levels—affects some 38 million Americans, or about 12% of the population. Treatment includes lifestyle changes, including diet and exercise, as well as prescription medications, blood sugar monitoring, and insulin therapy, the total costs of which are estimated at some $412 billion annually.
As the costs and incidence of type 2 diabetes continue to rise, scientists are searching for more noninvasive, inexpensive treatments. And now, a new study by British researchers may have found one—long-wavelength red light. Their results were published in the February 2024 issue of the Journal of Biophotonics.
The Study
Previous research has established that long-wavelength light between approximately 650–900 nanometers (spanning the visible through to the near-infrared range) can increase mitochondrial production of ATP, which reduces blood glucose in animals. To explore the impact of 670 nanometer red light on humans, the researchers recruited 30 healthy participants who were randomized into two groups: half were exposed to 15 minutes of red light, and the other half (the placebo group) were not.
Prior to treatment, all participants undertook a fasting oral glucose tolerance test (OGTT), consuming 75 grams of glucose in 150 milliliters of water and then using a finger stick test to measure their blood glucose levels every 15 minutes for two hours.
Within seven days, participants received a second OGTT, but this time the treatment group also received 15 minutes’ exposure to red light 45 minutes before taking the OGTT. All participant again recorded their blood glucose levels every 15 minutes for two hours after drinking the glucose, and the results showed that those who received the red light exposure exhibited a 27.7% reduction in blood glucose levels following glucose intake and a r 7.5% reduction in maximum glucose spiking.
Conclusions
While the study was conducted in healthy individuals, the non-invasive, non-pharmacological technique has the potential to have an impact on diabetes control after meals, the researchers said, as it can reduce damaging fluctuations of blood glucose in the body that contribute to aging.
“Our study has shown that we can use a single, 15-minute exposure to red light to reduce blood sugar levels after eating,” said lead author Michael Powner, PhD, senior lecturer in neurobiology at City University in London. “While this has only been done in healthy individuals in this paper, it has the potential to impact diabetes control going forward, as it could help to reduce potentially damaging glucose spikes in the body after meals.”
The researchers also noted that the study suggests that prolonged exposure to blue light may have the opposite effect, helping raise blood glucose levels. Given the prominence of LED lighting and the fact that LEDs emit blue light with very little red, the authors suggest that this may be a potential public health issue.
“Long-term exposure to blue light is potentially toxic without red,” said co-author Glen Jeffrey, PhD, of University College London. “Blue light on its own impacts badly on physiology and can drive disrupted blood sugars that may, in the long run, contribute to diabetes and undermine health spans.”
