Many times I have written about the need for sunlight to stimulate the production of vitamin D, serotonin, endorphin and nitric oxide, which are all essential ingredients for the optimal health of the human being. Lately, as those of you know who follow this blog, I have also discussed the importance of circadian rhythms (CRS) and the influence of sunlight on properly regulating them.
The latest research on the subject shows that CRS that are influenced by artificial light at night (ALAN), are disrupted, and they are associated with increased risk of breast cancer, prostate cancer and many other maladies.[i] There are three factors that effect that disruption:
- Nighttime use of personal computers, mobile phones, electronic tablets, televisions and other devices, unnatural to the human being.
- More importantly, perhaps is the almost complete absence of daytime sunlight, whose blue-violet spectrum synchronizes the CRS and whose UVB spectrum stimulates vitamin D synthesis.
- Under natural conditions and clear skies, day/night and annual cycles of UVB irradiation set the rhythms, control vitamin D synthesis and regulate other numerous bioprocesses that strengthen the biological time structure. Those natural conditions exist for too few of the population.
Disrupted CRS had also been found to inhibit the efficacy of Doxorubicin, a chemotherapy agent.[ii] The researchers believe that the reason is that night light disrupts the production of melatonin, which helps to produce sound sleeping habits. They performed experiments on rats who carried human breast cancer cells, supplementing melatonin and then measuring the action of Doxorubicin on the clearing of the cancer cells, which had previously been impervious to the action of the drug. the results were that Cancer latency was prolonged before the appearance of full tumors, and the efficacy of the drug was fully restored. Bright sunlight, followed by darkness during sleeping hours might have been an even better therapy.
Reading these materials taught me a great deal about why lack of sunlight is so closely associated with cancer and other diseases. I now know that I have some bad habits that need to be reversed. From now on, early to bed and early to rise!
Whenever possible, adjust your sleep habits to what God intended, and get your sunlight! It is likely that your health will improve, and so will your mood!
[i] Smolensky MH, Sackett-Lundeen LL, Portaluppi F. Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases. Chronobiol Int. 2015 Sep 16:1-20. [Epub ahead of print].
[ii] Xiang S, Dauchy RT, Hauch A, Mao L, Yuan L, et al. Doxorubicin resistance in breast cancer is driven by light at night-induced disruption of the circadian melatonin signal. J Pineal Res. 2015 Aug;59(1):60-9.