On those nights that you just can’t fall asleep, popular wisdom suggests that you drink warm milk, and there may actually be some kernel of truth behind that. Milk contains melatonin and it may be a low level of that hormone that’s preventing you from getting those zzz’s. Melatonin, which is released by your pineal gland, is responsible for regulating your sleep/wake cycle; when you have a lot, it causes sleepiness, and too little makes you feel awake. Each, of course, has its place but a problem occurs if you have too much or too little at the wrong times.
So how does your pineal gland know how much melatonin to make? It’s typically controlled by the circadian rhythms or your biological clock, an approximately 24-hour internal clock that affects when we sleep, eat, as well as body functions such as brain wave activity, hormone production and more. These circadian rhythms are influenced by light, among other factors.
This blog will discuss how a certain type of light – blue light – can impact melatonin production and how lower levels of that hormone could be a contributing factor to cancer and other diseases.
The Blue Light Epidemic
There’s been a lot written lately about how too much screen time on devices, such as smartphones, tablets, personal computers, and other sources such as LED lights – especially late at night – can make it more difficult to get to sleep. The problem stems from the blue light emitted from these screens and light bulbs.
Blue light, which has a short wavelength (between 400 and 500 nm) and can be found in sunlight as well as artificial light, interferes with our bodies’ production of melatonin. The blue light emitted from sunlight during the day helps to keep us alert and awake, but at night it interferes with the naturally occurring melatonin production which typically begins to be secreted a couple of hours before it is time for bed. If you don’t have enough melatonin, it not only makes it harder to get to sleep, but it can also reduce REM sleep, which is when we experience vivid dreams and can help us better handle stress and process memories, among other health benefits.
Blue light emitted at nighttime has a greater impact on melatonin suppression than other types of lights. A study conducted by Harvard University found that, compared to green light, blue light delayed melatonin production twice as long and had a similar impact on shifting our biological clock or circadian rhythms.
Melatonin and Cancer
The shift in our biological clock and production of less melatonin could contribute to cancer and other diseases. Researchers have looked for a connection by studying shift workers. Research conducted by the International Journal of Cancer found that the prevalence of breast cancer increased 30 percent for shift workers compared to the general population of women, while other studies found an increase in prostate cancer among male shift workers. One hypothesis is that the reduced level of melatonin could be a factor in the disease. Another study, cited in The Environmental Health Perspectives, suggests a connection between residential outside light and an increase in breast cancer in some women.
Since sleep allows the body to repair cells and DNA damage, control cell growth, regulating genes and boost the immune system, among other functions, it seems to follow that any disruptions to sleep over a period of time could have a potential negative impact. Also, since melatonin helps safeguard against DNA damage and tumors, reduced levels of melatonin can be problematic. Additionally, melatonin can reduce the amount of estrogen that the body releases, so lower melatonin levels could increase a woman’s estrogen level, which could contribute to breast cancer. Given the protection that melatonin can provide against cancer, some researchers are even experimenting with adding melatonin to the drug regiment in treating breast cancer.
But it’s not only cancer, blue light could also be a contributor to diabetes, heart disease and other illnesses. A Harvard study found that people’s blood sugar become elevated by changing their circadian rhythms. Also, poor sleep makes people more prone to accidents, becoming overweight and obese, and can worsen mental health issues.
The Popularity of Blue Light
With the health concerns of blue light, does it make sense to just avoid it? LED and compact fluorescent light bulbs, which emit a lot of blue light, have become very popular because of the energy efficiency and environmental benefits they offer. LEDs can use 75 percent less energy than incandescent bulbs, while lasting 25 percent longer. These energy benefits are becoming more important along with the growing concerns of climate change. In 2007, the U.S. government issued an energy efficiency program promoting the use of higher efficiency bulbs, making it harder to get traditional incandescent ones. With the push toward environmental and energy conservation, the popularity of higher efficiency lighting – particularly LED bulbs – will only increase.
The good news is that there is now a healthy alternative to traditional LED lights, sometimes referred to as human-centric or circadian friendly lights, that are designed to maintain the body’s natural circadian rhythms and support melatonin production. Some solutions simply filter the LED light which reduces energy efficiency. Other solutions rely on the combination of multiple channel LEDs, which can offer better tunability of the output spectra at, again, the cost of energy efficiency. Aurea, on the other hand, takes advantage of highly efficient, single channel blue LEDs and converts the source light based on human physiological needs throughout the day with minimal energy lost. This provides the best of both worlds – energy efficiency and healthy output. As our understanding of the impact of lighting on melatonin production and health grows, expect healthy LED solutions to become the new normal.