Artificial Light and Sleep
Two articles this week address one of the most pervasive public health issues in developed countries: sleep deprivation. The Centers for Disease Control and Prevention in 2014 labeled insufficient sleep a public health epidemic, citing its connection to motor vehicle crashes, industrial disasters, and medical and other occupational errors. Insufficient sleep is also linked to increased risk of chronic diseases such as hypertension, diabetes, depression, obesity and cancer as well as increased mortality.
Both articles place blame for sleep disturbance on artificial light. The first article, from NBC News, Sleepless in America: how digital devices keep us up all night, describes how blue light from electronic screens—televisions, phones, computers, tablets, readers—blocks the production of melatonin that makes us sleepy. Recommendations include removing electronic devices with screens from the bedroom and turning off all screens an hour before bedtime.
Another article from ScienceDaily reports on a study published in the Journal of Biological Rhythms that looked at “two traditionally hunter-gatherer communities that have almost identical ethnic and sociocultural backgrounds, but differ in one key aspect—access to electricity.” Both communities arose at about the same time, and both had about the same lag time between going to bed and falling asleep, but the group with electricity slept almost an hour less per night than the group without electricity, in both summer and winter. The researchers concluded that having access to electrical lights allowed one group to stay up later and thus sleep less.
Although both articles deal with artificial light and sleep, the mechanisms behind the lack of sleep are different. In the article about electronics and blue light, the light’s effect on the body’s melatonin production interferes with sleep. Individuals go to bed but cannot sleep. In the study of access to electricity, being able to stay up later with electric light allows individuals to delay going to bed. Once they go to bed, they fall asleep in roughly the same amount of time as those without electricity. Apparently electric light before sleeping does not interfere with the ability to fall asleep in the way that watching television or using a computer or mobile screen does. Until further research tells us otherwise, before bed go ahead and read, play a game, or socialize by electric light, but in ways that don’t involve screens.
Promoting Brain Health
This week brought several articles guiding us in optimizing brain performance. A news article from Reuters reported on a study finding that the amount of trans fats consumed in the diet is related to performance on a memory test among men under age 45. Each additional gram of trans fat per day matched to 0.76 fewer words identified correctly. There was no association between trans fats and memory performance for people over age 45. As we reported last week, trans fats are in many processed foods including cakes, cookies, crackers, stick margarine, microwave popcorn and more. The US Food and Drug Administration last week announced a ban on artificial trans fats within three years.
A second article published in ScienceDaily reported on a study indicating that “both a high-fat and a high-sugar diet, compared to a normal diet, cause changes in gut bacteria that appear related to a significant loss of ‘cognitive flexibility,’ or the power to adapt and adjust to changing situations.” Both the high-fat and high-sugar diets changed the types of gut microbes in male mice, with sugar having a greater impact on the numbers of different microbes and each diet producing different mixes of microbes. The high-sugar group was significantly impaired in tests of spatial memory compared to mice on a normal diet. The study authors conclude that changes in the microbiome may contribute to cognitive changes associated with eating a Western diet. An article in The Atlantic summarized studies from the last several years regarding manipulations of gut bacteria and the effects on autism, anxiety, depression, and other disorders. The only specific recommendation we can take from this article for our own lives is that yogurt promotes gut bacteria that may help us keep calm. Look for much more research on food, gut bacteria and brain function in the next few years.
A final article is a report from the University of Southern California finding that air pollution may affect the brains of older women. A study found that those “who lived in geographic locations with higher levels of fine particulate matter in ambient air had significantly smaller white matter volumes across a wide range of brain areas.” White matter in the brain is analogous to cables connecting a computer network, important to brain function.
Anyone who has spent time with individuals suffering from memory loss or reduced brain function will recognize the wisdom of caring for our brains. Cutting trans fats from the diet, reducing sugar consumption and cleaning up our air, whether individually or as a community, may all promote optimal brain function.
This post is part of a regular series that summarizes and highlights recent Your Health items and trends. Readers can follow CHE’s Your Health news feed or subscribe via RSS.
While individual actions to safeguard or improve health are important, we cannot individually address broad issues regarding pollutants, food supply, access to health care, poverty, climate change, infectious diseases and other issues that impact the health of individuals and communities. Join CHE to strengthen the science dialogue on environmental factors impacting human health and to facilitate collaborative, prevention-oriented efforts to address environmental health concerns.
Bringing attention to specific resources and findings does not mean CHE endorses or validates them. We highlight the emerging science and its implications for Your Health, knowing that thinking will continue to evolve as new studies are published.