You need plenty of restful sleep in a dark, cool, quiet room at night for the health of brain and body. But it’s easy to develop one particular habit in the evening or at bedtime that makes us more vulnerable to insomnia, being overweight and even cancer.
If going to bed has turned into a near-sleep experience, meaning you toss and turn without deep sleep, you can probably blame your electronic gadgets.
Most of us work during the day under electric lights in an office, stare at an LCD screen, and then use our smartphones and tablets, or e-readers, in the evening.
But when we do that, we warp the body’s preferred cycle of sleeping and waking. And studies show that the result of all that artificial lighting is a dark future for your health.
“It’s become clear that typical lighting is affecting our physiology,” warns researcher Richard Stevens who has been studying the effects of lighting for 30 years. “But lighting can be improved. We’re learning that better lighting can reduce these physiological effects. By that we mean dimmer and longer wavelengths in the evening, and avoiding the bright blue of e-readers, tablets and smart phones.”
Longer wavelengths at night means more red and yellow lights and less blue.
At night, as you get ready for sleep, the body is supposed to secrete more melatonin, a hormone that both increases your sleepiness and helps the body defend against cancer. But when the blue light of a smartphone or video screen enters your eyes, production of the hormone is suppressed. That can throw off the body’s natural circadian (daily) rhythm.
“We don’t know for certain,” says Stevens, “but there’s growing evidence that the long-term implications of this (type of light at night) have ties to breast cancer, obesity, diabetes, and depression, and possibly other cancers.”
Stevens cites a study that shows that if you read a book at night, your body produces more melatonin than if you use an e-reader.
“It’s about how much light you’re getting in the evening,” he says. “It doesn’t mean you have to turn all the lights off at 8 every night, it just means if you have a choice between an e-reader and a book, the book is less disruptive to your body clock. At night, the better, more circadian-friendly light is dimmer and, believe it or not, redder, like an incandescent bulb.”
The easiest way to keep blue light from affecting your sleep and your health is to minimize use of these blue light-emitting devices, like cell phones, close to bedtime. This allows your body’s natural circadian rhythm to start preparing your body and brain for sleep.
However you’re likely being hammered with blue-light from a multitude of electronic gadgets throughout your day—at the office, in your car, even at the supermarket. It’s quite literally impossible to escape them.
Something that can help defend against all the blue light is to take two nutrients called lutein and zeaxanthin. They are in the carotenoid family, like beta-carotene, which you probably know of, and they help your eyes filter out blue light. This also protects your eyes from aging and oxidative damage. [1]
Egg yolks, mangoes, corn, sweet potatoes, carrots, squash, tomatoes and dark, leafy greens have lutein and zeaxanthin. Kale has the most, but spinach, collards and bok choy aren’t far behind, according to the U.S. Department of Agriculture (USDA).
If you need to supplement, there are no “recommended daily intakes” specified for these because conventional medicine doesn’t appreciate the value of natural solutions for health. But Dr. Cutler has been using these nutrients with his patients for years, and he recommends at least 20-30 mg a day of lutein and from 2-4 mg of zeaxanthin to help your eyes block excess blue light.
[1] Krinsky, N, Landrum, J, Bone, R. “Biologic mechanisms of the protective role of lutein and zeaxanthin in the eye,” Annual Rev. Nutr. 2003;23:171-201.
