(NaturalNews) As you are sitting in a plane which is taking off or touching down late at night, or simply looking down at the world from a skyscraper, city lights are quite a sight to behold. You could almost say it's a modern day paradise. But little do you know that these lights could well be damaging your health on a daily basis. Recent research conducted at the University of Haifa has found that countries which are illuminated with the most artificial lights at night have the highest incidences of prostate cancer.
Details and Findings of Study
The study team had used information from a database of the Internal Agency for Research on Cancer, looking at the rates of lung, prostate and large intestine cancer in men living in 164 countries. This was then analyzed together with data on night lights, which were collated using satellite images from the Defense Meteorological Satellite Program. The latter data was adjusted to obtain the "amount of artificial light per night per person." Other factors also assessed included electricity consumption, proportion of urban population, and socioeconomic status, among others.
Using various statistical methods, the researchers found that there was a clear correlation between levels of artificial light at night and electricity use with prostate cancer rates. The next part of their analysis involved the measure "amount of artificial light per night per person", which the study team used to categorize the countries into three groups - those with little, medium and high exposure to artificial night lighting.
The association was significant. In the "little exposure" countries, the rate of prostate cancer was 66.77 persons per 100,000. For the "medium exposure" group, this figure increased to 87.11, which is an elevation of over 30%. The "high exposure" group exhibited a whopping increase, registering 157 persons per 100,000, which is almost double of the "medium exposure" countries.
Such findings are nothing particularly new. The same researchers, for example, had previously found a link between artificial night light exposure and breast cancer rates.
The link is clear, although the reasons are not. The study team has theorized that the association between artificial light and cancer could be due to a few possible reasons, for example melatonin production being inhibited, the immune system being suppressed, or the body's natural biological clock being "confused".
The Role of Melatonin
Among these possibilities, the melatonin connection is likely to have significant bearing. Melatonin is a hormone which is produced by the pineal gland in the brain. It helps to regulate other hormones as well as the body's wake and sleep cycles. Darkness stimulates its production, while light has a suppression effect. Besides exposure to excessive night light, getting too little light during daytime can also affect melatonin production.
Melatonin is believed to be a powerful antioxidant which has positive effects on the immune system. It is also believed to affect the aging process.
With regard to cancer, numerous studies have previously shown an inverse correlation between melatonin levels and breast cancer risk; the same has been noted for prostate cancer. Even lab studies have discovered that low levels of the hormone encouraged the growth of certain kinds of breast cancer cells, whereas the addition of melatonin suppressed their growth. For prostate cancer, too, the inhibition of prostate cancer cell growth was shown in lab studies.
Further, research conducted from 1992 to 2003 also suggested that melatonin helped lengthen the lives of persons who were already diagnosed with cancer. This applied to all types of solid-tumor cancers. In those studies, no serious negative effects with the use of melatonin were noted. In addition, in lab studies, melatonin supplements helped to significantly increase the survival time of rats which had advanced and untreated breast tumors.
This scientific evidence helps explain traditional wisdom and intuition that it is better to sleep at night, and in total darkness. Are melatonin supplements safe? This may not be totally clear, and your guess is as good as mine. The best thing we could do is perhaps to improve melatonin production as naturally as possible, and that entails sleeping at night in a room which is as dark as possible, using window shades if necessary, and exposing ourselves to as much natural light as possible during the day.
A side effect of that? More sunshine, and hence more vitamin D, too. Together with melatonin, that sure forms a potent duo.