Artificial light slows down the burning of fat

Animal experiment shows influence of persistent light on brown adipose tissue

Continuous light throughout the night brings the internal clock from the clock - and causes overweight. © Base64 / (CC BY-SA 3.0)
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Dick by artificial light - but how? Permanent light apparently inhibits the activity of brown adipose tissue, which is primarily responsible for the burning of fat. This is shown by animal experiments, which also confirm the fattening effect of the disturbed internal clock. A targeted activation of the brown adipose tissue could, however, help against these metabolic problems, scientists write in the magazine "Proceedings of the National Academy of Sciences".

Artificial light disturbs the natural day-night rhythm of man. If our internal clock is out of tune, it will not only affect the work of our brain. It can also cause problems for our metabolism and even cause overweight. However, what lies behind this connection between artificial light and body weight is still unclear.

More light - more fat

But fat is not the same fat: there are so-called white, but also brown fat in the body of mammals. The unpopular hip gold in humans consists of white fat cells that store excess energy in the form of fat. In contrast, the so-called brown fat cells have the opposite effect: like a kind of heating unit, they burn energy sources - thus counteract overweight. This happens in the very numerous cell power plants - the mitochondria, which are responsible for the yellow-brownish color of this particular fatty tissue.

The researchers led by Sander Kooijman of Leiden University have now investigated by means of experiments in mice, whether this brown adipose tissue could play a role in the known Dick-Mach effect by daylighting artificial light. They exposed three groups of experimental animals to different illumination times for five weeks: the rodents spent either 12, 16 or 24 hours in artificial light.

Light throttles brown fat cells

The results initially confirmed the known effect of artificially extended day: Although all of the animals had taken the same amount of food to him those mice developed in the long lighting duration significantly more fat tissue. Now the researchers devoted themselves to the comparative analysis of the brown adipose tissue. Result: They found in the mice, which were constantly exposed to light, signs that the activity of their brown fat cells was restricted, so that comparatively little energy was burned in them. display

According to the researchers, these results suggest that this lower brown-fat cell energy consumption is responsible for the increase in energy-storing adipose tissue. The activation of brown fat cells could potentially improve on this effect of postponed posttyration, say the researchers. Whether this is possible, however, must first be shown in further studies. (PNAS, 2015; doi: 10.1073 / pnas.1504239112)

(PNAS, Kooijman et al., May 12, 2015 - MVI)