When it comes to treating type 2 diabetes, we usually focus on food and exercise. We might sometimes talk about sunshine and health in relation to vitamin D, but that is not what we’re referring to today.
What we’re talking about is a new study presented at the European Association for the Study of Diabetes 2023 conference, which demonstrated how exposure to a specific light can drastically improve type 2 diabetes.
Our bodies are attuned to a natural internal clock, often referred to as the circadian rhythm. This rhythm affects our sleep, metabolism, and other bodily functions. When our internal clock goes out of sync, it can increase the likelihood of developing health issues, including metabolic diseases such as diabetes.
The strongest reset button for our circadian rhythm is natural daylight. However, many of us spend our days inside buildings, under artificial lighting.
The authors of this study wondered whether an increase in exposure to natural daylight could help people with diabetes better control their blood sugar. They were also keen to understand if it might help our bodies to absorb and use nutrients.
A team led by scientists from Maastricht University in the Netherlands recruited 13 participants, all of whom had type 2 diabetes.
The participants had an average age of 70 years and spent time under two different lighting conditions: natural daylight through windows and artificial LED lighting.
Each exposure lasted 4.5 days with a break of around a month in between.
During the daytime, the intensity of natural light was highest around midday, clocking in at about 2,453 lux, whereas artificial light was a constant 300 lux. Evenings had dim lighting, and nights were spent in complete darkness.
Other than lighting, all participants had similar meals and activity routines to ensure that no other factor influenced the findings.
The results were promising:
1. Participants’ blood sugar levels remained within the normal range for a longer time when exposed to natural daylight compared to artificial light (59% vs. 51% of the time). This indicates better blood sugar control with natural light exposure.
2. Under natural daylight conditions, participants found it easier to shift their main energy source from carbohydrates to fat. This is an important metabolic switch that people at a higher risk of type 2 diabetes find hard to make.
3. Genes that control circadian rhythm were more active during the natural light exposure period, suggesting a more aligned internal clock.
4. Resting energy use and core body temperature were similar under both lighting conditions.
5. The way the participants’ bodies responded to a meal (in terms of insulin production) was also largely similar under both conditions.
This means that the type of light we’re exposed to affects our metabolism. If your job or lifestyle keeps you mostly indoors with minimal exposure to natural daylight, it could influence your metabolic health and your management or risk of type 2 diabetes.
Therefore, it is a good idea to get as much daylight as possible and ideally spend some time outdoors every day.