Light Pollution! LAN (Light at night)
According to Dr. Abraham Haim the most dramatic environmental change in the last 130 years is the phenomena of LAN (light at night) This results in “light pollution” which is linked to cancer, heart disease, obesity and macular degeneration! His ongoing research is being done at the Israeli Research Center for the Collaboration of Photochronobiology and he has published numerous papers on these subjects
Season Acclimatization of the Thermoregulatory System
We know that there is a cyclical rhythm of our seasons. Shorter days and longer nights signal winter. Longer days and shorter nights are a signal for summer. This is a signal for birds to migrate, bears to hibernate, leaves changing etc.
NOW days are not bright and nights are not dark. The most dramatic environmental change in the last 130 years is the phenomena of LAN (light at night) producing light pollution. This is upsetting our important biological rhythm in nature.
It is interesting that in the eye the retina has two different types of photoreceptors, image and non image receptors. The image receptors are responsible for our sight sending impulses to the occipital lobe for the perception of vision. The second group called the non image photoreceptors send fibers to the hind brain and autonomic nervous system adn then fibers go to the pineal gland. The Pineal gland secretes melatonin at night and it accumulates melatonin during the day. This process is directly dependent on the circadian rhythm of night and day.
Several interesting studies were reported by Dr. Haim. He demonstrated that light exposure at night to the Voll Rat affected their reproductive system and their ability to adapt to cold at night. In one study Voll rats where repeatedly exposed to light at night. All of the animals died due to their inability to adapt to cold changes at night.
A blind mole rat responds to changes in diurnal rhythm – increasing day light produces changes in body temperature- study by Haim
Voll study- light at night affects the reproductive system and the ability to adapt to cold at night- all rats died in this study. Dr Haim describes this change as “Seasons out of time” This experimnat was repeated by giving the rats melatonin at night. This had no effect at the explannation is that light at night in addition to affecting melatonin secretion also acts as a stressor affecting the levels of adrenalin and cortisol.
Shift workers are at a high risk of developing breast cancer
Increase incidence of light exposure at night which causes a decrease in melatonin production and increase in abnormal cortisol at night
Increase incidence of breast cancer with LAN
A research group looked at geographic maps of night lights and compared them with maps of breast cancer. There was a very high correlation with the incidence of breast cancer and the areas of the world with high light concentration at night. As a control income level was analyzed.
High or low income does not make the difference or did the incidence of
Mice injected with human breast cancer cells
Mice with light interference at night had largest tumor and mice receiving
melatonin at night had lower tumor growth. The group with the lowest growth was the mice that had 8 hours daylight and 16 hours of darkness.
Prostate cancer also correlates with countries with LAN
Study in mice injected with prostate cancer cells. The prostate cancer cells grow more with increase with light interference at night
Melatonin protects breast cancer and prostate
Studies in rats looked at the affects of wave length of light on tumor volume
Blue illumination- much greater tumor volume. Blue light blocks the production of melatonin. Red illumination had very little affect on tumor volume (Red light does not block melatonin secrection)
Melatonin and heart attacks
There is an increase incidence of heart attacks in early morning due to an increase in the clotting of blood. A study was done looking at Prothombin time (clotting time) and light exposure especially LAN
A long day with light interruption had a much lower PT which increases the risk of clotting
Increase incidence of atypical Lymphocytes
in a mouse study there was a higher incidence of atypical lymphocytes with a short amount of light during the day and light interference at night. There was lower atypical lymphocytes with a short day, no light interference at night and melatonin at night. Shorter days with light exposure at night correlates with increase incidence of flu in the winter
Blue light at night decreases melatonin secretion
Mercury in light bulbs shifts the wavelength toward the blue spectrum. This is especially true with the new LED and hasmet light. The blue light has greater stimulation of the non photoreceptor cells (These regulate melatonin) than the photoreceptor cells. The LED and florescent lights increase pollution! These light bulbs might be more economical but this shift in blue light is potentially extremely harmful for your health and vision!
Obesity is also linked to melatonin
studies in rats have documented there is an increase incidence of obesity with light exposure at night!
Light and Macular Degeneration
Dr. Haims studies support the article that I discussed a few months ago on the affects of melatonin levels in macular degeneration. The article was called- Resetting the Pineal Clock, Volume 1057, published December 2005 Ann. N.Y. Acad. Sci. 1057: 384–392 (2005) by CHANG XIAN YI et al. They proposed that the decrease in melatonin in the elderly may be an important factor in RPE dysfunction, which is a well known cause for initiation of AMD. 100 patients were given 3 mg of melatonin at night for a minimum of 3 months. Fifty-five patients were followed for more than 6 months. At 6 months of treatment, the visual acuity had been kept stable in general. The majority of patients had reduced pathologic macular changes. We conclude that the daily use of 3 mg melatonin seems to protect the retina and to delay macular degeneration. No significant side effects were observed.
Turn off the lights at night! Please strive for total darkness in your room at night. Obtain block out drapes, no night light at your bedside (insert an inexpensive motion detector lamp), remove the TV and alarm clock light from your room. The smallest amount of light even hitting your skin can suppress the pineal and melatonin secretion. Consider taking 3 mg of slow release melatonin at night. Strive to get adequate sun exposure during the day.
A common question from patients. But Dr. Kondrot don’t you recommend blue light as a treatment for my eyes?
The blue light in your light treatment is a different wavelength and intensity than the harmful blue light you are receiving in your home and work from mercury lamps. Blue light in any form during the night is suppressive of melatonin. Do your light therapy during the day when blue light is helpful. Minimize all light exposure at night. When the sun sets it is time to turn off the lights and go to bed! Try this and see what happens to your vision and health!