So we already plublished an article about how good sunlight is for your health. Here we have another fact. If you expose yourself to the sun every day for not too long it reduces the chance of colon cancer. That’s what researchers from the Leiden University Medical Center (LUMC) discovered by exposing mice to UV radiation.

Mortality from colorectal cancer is way lower in countries with a lot of sunshine was already a fact, but that exposure to sunlight may inhibit intestinal tumors was not proven. A research group guided by Dr. Frank and Dr. Els Gruijl Robanus proved that mice with a mutation in the APC gene ‘spontaneously’ developed cancer.

A part of the mice have been shaved and placed six weeks after birth to a moderate dosage of UV radiation, wherein their vitamin D levels significantly increased without being burned. Another part were administered with vitamin D during the same period through the diet. A control group received no vitamin D and no sunlamp.

The mice that received vitamin D through the diet and in the mice that were sunlamps both inhibited the growth of the intestinal tumors. ““We showed that there is a big chance that there is a link between exposure to UV radiation and a reduced risk of colon cancer”. according to De Gruijl.


However, the researchers discovered that sunlamps had more effect than vitamin D. “Except that the tumors of the mice that were irradiated with UV didn’t grew so hard, the tumors were much less life-threatening” De Gruijl explains. The protective effect of sunlight is apparently not just Vitamin D, The Gruijl: “It is a fact that the influence of UV in sunlight is also very important, but we need to do additional research to find out  if sunlight releases other substances that prevent colon cancer”

The scientific article is published online on the International Journal of Cancer