TEL AVIV – A new Israeli study shows that artificial light at night (ALAN) can cause weight gain and even lead to some types of cancer, ISRAEL21c reported.
The study, which was published in the International Journal of Obesity, demonstrates that artificial light disrupts daily rhythms and suppresses the production of melatonin, a hormone produced by animals and humans at night.
“In recent years there are a lot of studies that use ALAN as a proxy for different health issues including obesity. Some lab studies have examined how ALAN leads to body-mass gain among mice,” explains University of Haifa mathematics and economics PhD student Nataliya Rybnikova to ISRAEL21c.
“Melatonin is responsible for metabolic function, and ALAN also influences metabolic function in people. So we decided to check if there is an association between ALAN and body-mass gain,” she adds.
Rybnikova studied captured satellite images of artificial light emitted at night from more than 80 countries. She then compared the images with data on each country’s obesity rates.
After adjusting for other factors known to influence obesity — including the country’s average birthrate, dietary patterns, gross domestic product, and percentage of urban population — ALAN still emerged as a prominent predictor for obesity.
According to the World Health Organization, about 1,900 million adults are now defined as overweight (body mass index of 25 to 29.9) and about 600 million adults defined as obese (body mass index of 30 or higher).
Rybnikova worked on the study under the supervision of Haifa University professors Boris Portnov and Abraham Haim, who co-authored the 2013 book Light Pollution as a New Risk Factor for Breast and Prostate Cancers.
Melatonin also has anti-oxidant and anti-cancer properties which, when suppressed, contributes to higher rates of breast and prostate cancer.
Studies conducted in Israel have shown that higher levels of artificial lighting in a neighborhood correlate with a higher frequency of breast cancer and prostate cancer in that neighborhood.