Too Much Artificial Light Might Be Making You Fat

A new scientific study, published in the journal Proceedings of the National Academy of Science, has made a surprising revelation that artificial light exposure is linked with obesity in humans. According to the researchers, the light that comes out of the mobile screens, iPads and tablets that allows people to stay up late or work in the predawn hours can disrupt circadian rhythms in humans and have established through their study in mice that similar effects may be responsible for weight gain due to a reduction in brown fat activity.

Brown fat and white fat are two types of tissues where most of the mammals store fat. Although both types store energy, white fat releases its energy stores to power other cells, while brown fat produces heat from metabolising its contents. The researchers in the past years have been working to figure out a way to use brown fat to stimulate weight loss. They were successful in identifying a protein called β3adrenergic receptor that, when activated, encourages brown fat cells to burn off more fat and produce more heat.

The team of scientists in The Netherlands, led by Patrick Rensen of Leiden University Medical Center, carried out a study to test the relationship between light exposure and brown fat activity by exposing groups of mice to artificial light for 12, 16, or 24 hours per day and monitored their levels of β3 adrenergic receptor activity. They also closely monitored the rate at which energy molecules, such as glucose and fatty acids, were absorbed from the bloodstream by brown fat tissue.

After five weeks of light exposure, it was observed that although the mice slept the same total amount of time and ate and exercised the same as the control mice, their base metabolism changed. There was a reduced activity of brown adipose tissue, or BAT. The 24-hour light exposed mice even packed on more fat than a group fed a high-fat diet.

According to Dr Patrick C.N. Rensen, head of Endocrinology Research at Leiden University Medical Center in The Netherlands, “As underlying mechanism we identified that brown fat, a tissue that combusts large amounts of fat into heat, becomes less active (when exposed to excessive light) resulting in reduced energy expenditure that leads to an increase in body fat. We now show that brown fat adapts its activity to changes in circadian rhythmicity. This is convenient for seasonal adaptations to outside temperature.”

The issue arises when our circadian rhythms gets altered due to social or work-related activities and spend too much time under the light bulb or any other form of artificial light. These habits have negative implications and might be the reason behind obesity epidemics affecting modern societies, says Rensen.

On a concluding note, Rensen believes that by restricting work and other activities to day time and sleeping in dark bedrooms might help a great deal in losing weight.

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