Geschatte leestijd: 2 minutenNew research has shown that lack of sunlight can lead to weight gain in winter. Conversely, exposure to sunlight causes fat cells under the skin to shrink.
Weight gain in winter
Before delving into the research, I must first emphasize that in practice, there can be various reasons why many people gain weight in winter and lose weight in summer:
- A conscious choice. When thick clothing disappears back into the closet, it’s time for many people to think about dieting again.
- The holidays
- Less activity in winter due to bad weather
- Deficiency in vitamin D. Although the influence of vitamin D on body weight varies from study to study, some research shows lower weight with higher vitamin D levels. Since we need sunlight to produce vitamin D, there could be a correlation here.
However, new research from the University of Alberta shows a much more direct effect of sunlight on fat cells [1]. The study demonstrates that fat cells located just under the skin decrease in size under exposure to blue light from the sun (the light we perceive).
Senior author of the study, Peter Light (no joke), explains:
When the blue light from the sun penetrates our skin in the summer and reaches the fat cells just below, fat droplets decrease in size, allowing them to leave the fat cell. In winter, it’s the opposite.
Peter Light, professor pharmacology & director of Alberta Diabetes Institute.
The professor warns, however, that this is only an initial observation and that seeking sunlight for weight loss is not recommended and/or safe. For example, it is still not clear how long and with what intensity the exposure to light should be to achieve this effect (and to what extent this outweighs the risks of sunlight).
However, the new discovery could lead to further research and possibly, eventually, to new treatment methods based on light therapy for obesity and related diseases such as diabetes.
Accidental discovery
Speaking of diabetes: The researchers stumbled upon this discovery by chance. They were working on the development of modified fat cells that should produce insulin when exposed to light to combat type 1 diabetes. In the control group (with normal fat cells), they then observed the reaction of the fat cells to the light. Because there was nothing about this in the medical literature, they knew they had made an important discovery that deserves further investigation.
Based on the findings, Light considers that this mechanism may be some kind of biological clock. It’s still a big assumption, but it’s possible that the light captured by our eyes and influencing the day-night rhythm also affects fat cells just below the skin in this way. Perhaps it works like a sensor that takes into account the season and the required fat storage.
Only time will tell.
References
- Katarina Ondrusova, Mohammad Fatehi, Amy Barr, Zofia Czarnecka, Wentong Long, Kunimasa Suzuki, Scott Campbell, Koenraad Philippaert, Matthew Hubert, Edward Tredget, Peter Kwan, Nicolas Touret, Martin Wabitsch, Kevin Y. Lee, Peter E. Light. Subcutaneous white adipocytes express a light sensitive signaling pathway mediated via a melanopsin/TRPC channel axis. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-16689-4
