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Researchers say that just 15 minutes of red light therapy could help reduce blood sugar levels by almost 30%. Collab Media/Getty Images
  • New research shows that red light therapy reduces blood sugar by almost 30% in healthy adults.
  • The researchers found that just 15 minutes of exposure to bare skin was enough to elicit benefits.
  • It’s too early to determine whether red light therapy could be used in diabetes treatment, but the results are promising.

Researchers in the United Kingdom have investigated the effects of red light on blood sugar levels.

Their findings, published February 20 in the Journal of Biophotonics, could lay the groundwork for new therapy options for type 2 diabetes (T2D).

The scientists found that utilizing a specific wavelength of red light for just 15 minutes on bare skin affected blood sugar in two beneficial ways.

“A single dose of 670 nm red light in a healthy person can reduce blood glucose and the way it peaks after a standard blood glucose tolerance test,” Dr. Michael Powner, PhD, a senior lecturer in Neurobiology at the University of London, and first author of the research, told Healthline.

Researchers have previously investigated the effects of light therapy on other diseases, including cancer and macular degeneration.

It’s not clear yet how these new findings could be used as a safe and effective adjunct treatment for people with diabetes. However, the implications are promising, given the positive effects of red light therapy on blood glucose.

The potential for such a therapy for diabetes is intriguing as it could be delivered without drugs or surgery simply by applying red light to the skin for a prescribed amount of time.

For their study, researchers recruited 30 healthy participants with an average age of 40 years old.

Half of them were assigned to the light therapy group, while the other half were assigned to a placebo group. Participants had no known metabolic conditions and were not taking any medication.

BMI (body mass index), which is an important risk factor for metabolic disease, was not recorded for the participants.

Over a 7-day period, both groups underwent two fasting oral glucose tolerance tests — a standard test that doctors use to identify how well the body processes sugar. It is frequently used to diagnose diabetes.

For the test, participants had to fast for at least 10 hours and then ingest a drink with a predetermined amount of glucose (sugar) in it. Following ingestion, participants had their blood sugar measured every 15 minutes for 2 hours. These measurements created a baseline reading for participants’ blood sugar.

Within 7 days, another blood glucose test was administered. This time, participants received either light therapy or a placebo. Participants applied the red light to bare skin on the upper back for 15 minutes. This was done 45 minutes prior to the blood glucose test being administered. The placebo group was put through the exact same scenario, except the light was never turned on.

Researchers then compared the comprehensive results of the oral glucose tolerance tests between the red light and placebo groups, as well as comparing individuals within each group.

Compared with the baseline reading, the group that received the light therapy had a nearly 30 percent (27.7%) drop in blood glucose levels averaged over 2 hours. Compared to the placebo group, the light therapy group had a 7.3% reduction in the total blood glucose levels observed over time.

Using red light also appeared beneficial in mitigating blood sugar spikes after ingesting glucose. Blood sugar spikes can happen after eating when glucose levels rise sharply in the bloodstream.

In their experiment, researchers found that individuals who received the red light therapy had sugar spikes that were less extreme, resulting in a 7.5% reduction in their peak (highest) blood glucose level.

Compared to the placebo group, the light therapy group had a 12.1% reduction in peak blood glucose levels.

Dr. Jennifer Cheng, section chief of endocrinology at Hackensack Meridian Jersey Shore University Medical Center in New Jersey, spoke to Medical News Today about the study and said additional research should be done to see if the results can be replicated on a larger scale.

“It will be interesting to see if this is replicated and if a certain amount of sunlight is needed to help maintain glycemic control. We always encourage our patients to go outside and exercise. This is another reason to encourage outdoor activities, but it remains to be seen if the studies can be verified,” Cheng told MNT.

There are different forms of light therapy that depend on the wavelength of the light being used.

The wave length can also affect the color and visibility of the light. In this experiment, and in other similar studies, the light used is a 670 nm red light, that is, a light with a wavelength of 670 nanometers.

This form of red light is known to affect cellular metabolism, which in turn affects blood glucose via the mitochondria, but the exact mechanisms are still not entirely understood.

Mitochondria are the cell’s powerhouse, using oxygen and glucose to produce ATP, the energy for the biochemical functions essential to life. The prevalent belief is that exposing mitochondria to 670 nm red light causes an increase in the production of ATP and, therefore, a greater demand for glucose.

“The exact mechanism remains unknown. Previous studies report that red light increases energy by burning glucose in mitochondria. So, perhaps increasing mitochondrial activity decreases glucose by drawing it out from blood,” said Powner.

Other forms of light therapy work in different ways and include blue light therapy, which is used for topical skin problems like acne.

Light therapy, which requires a high intensity light box, is used for seasonal affective disorder (SAD) and depression. Ultraviolet light can also be used to disinfect, sanitize, and kill microorganisms.

Researchers found that exposing healthy people to a specific wavelength of red light prior to consuming a sugar drink resulted in a nearly 30% drop in blood sugar compared to a baseline reading.

The red light also helped to control blood sugar spikes, resulting in a 7.5% reduction in peak blood glucose.

While it is intriguing to think of the applications for red light therapy as a diabetes treatment, the researchers say it is too early to tell if it would be safe and effective.