Defiant Health Radio with Dr. William Davis
Defiant Health Radio with Dr. William Davis
Is blue light damaging your eyesight?
Over the past decade, most of us have converted our home lighting to light-emitting diode (LED) bulbs, as they save a significant amount of energy, requiring 75-90% less energy than older incandescent lights. Personally, I converted the 50 or lightbulbs in my house to nearly all LEDs.
Most current LEDs emit, of course, visible light. But they also emit a significant amount of blue light and very little red and infrared (IR), in contrast to old-fashioned incandescent bulbs that emit some blue and a lot of red and IR. Remember when you had to change an incandescent bulb when it died? If you tried to unscrew it, it could burn your hand because the bulb was extremely hot. That’s the effect of red and IR that generates heat. Change a LED bulb and you can do so immediately, as the bulb is cool, even after dying just moments earlier. This is due to the absence of significant amounts of red and IR.
While well-intended to save energy, it is now becoming clear that the wholesale conversion to blue-emitting LED lighting has been exerting adverse health effects, especially visual. So let’s begin talking about the role of light, specifically blue wavelengths in this episode of the Defiant Health podcast, then about the role of red and IR in a future episode. _______________________________________________________________________________
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Over the past decade, most of us have converted our home lighting to light-emitting diode or LED bulbs, as they save a significant amount of energy, requiring 75-90% less energy than older incandescent lights. Personally, I convert the 50 or so light bulbs in my house to nearly all LEDs. Most current LEDs emit, of course, visible light, but they also emit a significant amount of blue light and very little red and infrared, in contrast to old-fashioned incandescent bulbs that emit some blue and a lot of red and infrared. Remember when you had to change an incandescent bulbs that emit some blue and a lot of red and infrared. Remember when you had to change an incandescent bulb when it died? If you tried to unscrew it, it would burn your hand because the bulb was extremely hot. That's the effect of red and infrared that generates heat. Change an LED bulb and you can do so immediately, as the bulb is cool, even after dying just moments earlier. This is due to the absence of significant amounts of red and infrared.
William Davis, MD:While well intended to save energy, it is now becoming clear that the wholesale conversion to blue-emitting LED lighting has been exerting adverse health effects, especially visual has been exerting adverse health effects, especially visual. So let's begin talking about the role of light, specifically blue wavelengths, in this episode of the Defiant Health podcast, then about the role of red and infrared. In a future episode I'll be also telling you more about Defiant Health sponsors Paleo Valley, our preferred provider for many excellent organic and grass-fed food products, and biodequest, my number one choice for probiotics that are scientifically formulated, unlike most other commercial probiotic products available today. I'd like to make you aware of a new source for our favorite microbe, lactobacillus roteri, and a skin formulation I designed that improves skin from the inside out. So, as I mentioned in the opening comments, as a society we've converted our lighting over to the LED blue emitting light bulbs, and it was done for good purpose. It was done to conserve energy. So federal regulations from Congress and the Department of Energy has essentially done away with incandescent bulbs, or most forms of incandescent bulbs, and we replaced them with LEDs. So it's not uncommon to have LEDs at work in stores in your home in the form of light bulbs. As well as TV screens, computer screens, tablets, smartphones they are all LED, so we are wildly overexposed to this LED.
William Davis, MD:You know what this reminds me of. This reminds me of the reducer saturated fat and cholesterol blunder created by misinterpretations of science, us dietary guidelines. It took us 40 to 50 years to recognize what a huge mistake this was. It took the elimination or reduction in saturated fat in total fat and increase in the intake of carbohydrates, specifically grain forms of carbohydrates as well as sugars, and the unrestrained proliferation of processed and ultra-processed foods to show us just how destructive this has been. Of course, in the world of diet it's caused epidemic, a nationwide, now a worldwide epidemic of overweight and obesity, type 2 diabetes and numerous other health consequences. I think there's a parallel here to this wholesale conversion, the replacement of incandescent bulbs with LED bulbs, and we're only starting to see it now, many years after this initiative was introduced.
William Davis, MD:Now, blue is not all bad. Blue light is not all bad. Let's review the light spectrum just for a moment because it helps to understand. So at the far short wavelength at the left, on most charts of wavelength of light, you'll see that blue is just after ultraviolet. Ultraviolet, of course, is the stuff you can't see that activates vitamin D in the skin. Then to the right, in a higher wavelength, is blue, and then we have visible light. Visible light is actually a very narrow part of the electromagnetic spectrum. And at the right we have red, visible, followed by infrared. Infrared-like ultraviolet cannot be seen. You can feel it as heat, but you cannot see it. But red and infrared have unique effects and that's the flip side of all this. Part of the problem is our wild overexposure to blue and lack of red. We'll talk about that and we'll talk about this even further in a future episode of this Define Health podcast.
William Davis, MD:Now, blue is not all bad. It has some positive aspects. It increases alertness, arousal, it improves cognitive function and, in some people, can reduce migraine headaches, though in other people it actually activates. So it's unclear why that discrepancy, but it does have brain effects that can be positive if you're exposed in the morning or midday and, of course, if you're exposed most in the midday. That's when you maximally activate vitamin d in the skin, with exposure to the uvb form of radiation just a little shorter wavelength than blue. So blue actually has positive aspects and that's actually why I converted my desk lamp some years ago to blue LED, because we were told that it increased alertness and cognitive function.
William Davis, MD:So I took my desk lamp, for instance, and replaced the two incandescent bulbs with two LED bulbs. Well, personally, I started to notice after a couple of years that my vision was deteriorating, so much so that if I worked at night, I could barely see the screen. I could barely read the text on a screen and images. If I watched a video, for instance, it was fuzzy, I had a hard time and it was worse at night. Now, why would that be? So I converted back to two incandescent bulbs. So incandescent bulbs, the old fashioned bulbs, are richer in red and infrared. They do have some blue, of course. They have visible light, but they are enriched in the red and infrared part of the spectrum, while the LED lights are visible light with lots of blue and very little red. So I converted my desk lamp back to two incandescent bulbs. Lo and behold, my vision normalized within 48 hours.
William Davis, MD:Now, one person's experience such as mine is not proof of anything, but it is consistent with what we're seeing and hearing and reading and experiencing nationwide, that is, a deterioration in visual acuity, with overexposure to blue, particularly later in the day. So what does excessive exposure to blue do, especially if it's done afternoon? So after about 4 pm blue starts to become a toxic factor and not a beneficial factor. So among the effects of excessive exposure to blue includes a reduction in visual acuity Not just in me, but it's been shown in other people that overexposure to blue, particularly in the afternoon and evening, reduces your visual acuity and that reduction in visual acuity over time can become permanent. It's not. It may be temporary at the beginning, but over months and years it becomes permanent. Part of that reason is damage to the retina. There are light-sensitive cells in the retina that is, the light-sensitive portion of your eyes called retinal ganglion cells, and this has been associated with glaucoma, development of glaucoma and other eye conditions. So exposure to blue later in the day has been associated with retinal damage.
William Davis, MD:It's also been associated with the development of cataracts. Recall that cataracts are the development of opacities in your lenses, in the lenses of your eyes, and as you have greater opacities in your lenses, this is cataracts and you can't see after a while. Light has a hard time penetrating the opaque cataracts. So there's an interesting experiment in which lenses were taken out of the eyes of pigs and exposed to blue light, red light, and examined to see whether they continue to transmit light or not. Now the pig lenses exposed to blue light developed opacities consistent with cataracts within 24 hours of continuous blue light exposure, suggesting that there's a time dependence, and it only took in these lenses that were taken out of the pigs, of course, exposed to blue light. It didn't take that long for blue overexposure to develop cataracts. And you know what I believe? I'm seeing this around me. I'm seeing people in their 40s and 50s. Cataracts were typically a problem of people in their 60s, 70s and onwards. I'm seeing people in their 40s and 50s now having to undergo cataract extraction or cataract removal surgery because their lenses are opaque and they can't see. And so I think this is a phenomenon being played out because of our overexposure to all the blue wavelength in our lighting and our devices.
William Davis, MD:Exposure to blue light also reduced the release of melatonin from the pineal gland. Recall that melatonin is the hormone of a circadian rhythm from the pineal gland. Recall that melatonin is the hormone of the circadian rhythm. It's a thing that surges later in the day and evening to facilitate sleep. So this is the reason why you hear this kind of advice. So avoid LED screens later in the day, because they reduce release of melatonin and cause sleeplessness. That's a real phenomenon. So blue light exposure later in the day disrupts sleep and disrupts your circadian rhythm.
William Davis, MD:Now more recent evidence also suggests that the effects of blue light go beyond the eyes and the components of the eyes, like the retina and lenses and it. Organs of your body don't respond to insulin and your pancreas thereby overcompensates by producing huge amounts of insulin. It's not uncommon to produce 10-fold more, 30-fold more, 100-fold more insulin, which leads to weight gain, especially abdominal visceral fat. It leads to all the consequences of insulin resistance that include impairment of cognition, alzheimer's disease, coronary disease, heart disease, type 2 diabetes, hypertension, dementia. So an increase in insulin resistance is very important, even a modest increase, because this effect induced by blue light is over and above that induced by bad diet, lack of vitamin D, lack of magnesium, sibo and endotoxemia. If you don't know what that means, please see my prior episodes of this podcast or my blog, williamdavesmdcom, or, of course, my books, such as the Super Gut Book, where I talk about how the bowel microbiome, through dysbiosis, sibo, small intestinal bacterial overgrowth and endotoxemia, adds to insulin resistance. Where here we have yet another factor adding to this very ubiquitous process that leads to so many diseases insulin resistance in this case, exposure, overexposure, blue light, especially later in the day. Now there's also evidence to tell us that exposure to blue light reduces tone in the vagus nerve, vagal tone and heart rate variability.
William Davis, MD:Recall that the nervous system is divided into two the autonomic nervous system, that is the nervous system that controls internal body functions that you're unaware of. So in other words, if you eat something let's say you eat an omelet you don't have to thank goodness, tell your esophagus and stomach to begin the digestive process. You don't have to tell your pancreas to release pancreatic enzymes. You don't have to tell your stomach to propel that chewed, partially digested food into the duodenum. All this happens, of course, beneath consciousness. This is all conducted by the autonomic or automatic, you can say nervous system, and a lot of that's controlled by the sympathetic and the parasympathetic nervous system, the two main components of that autonomic nervous system.
William Davis, MD:The sympathetic nervous system is the gas pedal on your physiology. It's the part of your nervous system responsible for fight or flight, excitement, arousal, getting out of danger, getting out of the way of danger. The parasympathetic system is the brake on your nervous system. It's the thing that's associated with relaxation, quiet meditation. So if we have exposure to blue light later in the day, it reduces these phenomena, as so is with the parasympathetic system, and it pushes you closer to anxiety, experiencing nervousness, phenomena related to excessive sympathetic tone, like hypertension, and there may even be more serious consequences. This has not been well charted, but we know, for instance, that people with reduced heart rate variability also have greater cardiovascular mortality. So does blue light exposure increase cardiovascular mortality? That has not yet been shown, but there is the potential by this effect that blue light can reduce heart rate variability. That may lead to these more serious complications.
William Davis, MD:Now there's also evidence to tell us that overexposure to blue increases the risk for macular degeneration. Of course this is the process that many older people experience. That is the most common cause for blindness. So there's deterioration vision because of this. There is the expansion of something called drusen. This is the material that accumulates in the retina. That leads to loss of vision, in macular degeneration, and blue light seems to stimulate the deterioration of retinal health and the accumulation of drusen.
William Davis, MD:There's also evidence that exposure to blue light, particularly later in the day, can accelerate the phenomenon of skin aging, breakdown of the dermal layer of skin. Recall that blue is right next to ultraviolet, so it shares some of the features of ultraviolet light. Now, those two frequencies ultraviolet and blue, as I mentioned, do provide benefits, but here overexposure can lead to an acceleration of skin aging. Both blue and ultraviolet Over-exposure to blue can accelerate cognitive decline. It's a slow, progressive process, but over-exposure to blue can actually have negative effects on the brain that can lead to decline in cognitive function.
William Davis, MD:Now we'll be talking in future about the benefits of red to counteract some of those effects of the blue. So just reducing your exposure to blue is insufficient. We've got to talk about also restoring or increasing your exposure to red, especially if you live in a climate where it's not possible to get sunlight all the time, because if you live where I do or a place like I do, where it's cold and it's gloomy and dark much of the year, right now I haven't seen the sun more than three days in the last month. So exposure to red helps in addition to reducing your exposure to blue.
William Davis, MD:And then there are adverse effects on the mitochondria. The mitochondria are the little organelles, they say, in your body's cells, such as those in your brain, in your retina, that are the energy generators, and they're very fragile. They depend on light. Mitochondria are the descendants of bacteria from billions of years ago that larger cells incorporate into their bodies, and these things became little organelles, energy producing organelles. They produce a form of energy called ATP, and it's the currency of energy production. It's the thing that gives you the drive, the movement ability to contract muscle, to walk, to run, to swim. So an adverse effect on mitochondria can lead to low energy and dysfunction of organs.
William Davis, MD:Well, overexposure to blue increases the production of something called a reactive oxygen species, and all that means is these are oxygen-containing compounds. That means these are oxygen-containing compounds like hydrogen peroxide that are damaging to DNA, rna, proteins and other structures and compounds in the cells of the body, and it damages the mitochondria. Now, these reactive oxygen species are counteracted by exposure of the mitochondria to red and infrared, and so that's why I say there's two sides of this coin overexposure to blue, lack of red, infrared, but for our current conversation, it's the overexposure to blue that increases the reactive oxygen species. That must be counteracted by exposure to red and infrared. But once again, this is an argument in favor of reducing your late-day exposure to the blue way-length of light. Now, before we go any further, let me tell you something about Defiant Health's sponsors, and when we come back, let's talk about how you can fix these problems, how you can undo some of the adverse effects of overexposure to blue, and in the future we'll talk about the lack of red and also take down some of the myths surrounding red light.
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William Davis, MD:For Defiant Health listeners and due to demand for reliable, convenient sources of lactobacillus roteri, our favorite microbe, I created two products MyRoteri that contains 20 billion counts of l rotary alone, and Gut to glow that, in addition to l rotary, has added marine source collagen, peptides, hyaluronic acid and the carotenoid astaxanthin, all combined to stack the odds in favor of beneficial skin effects. Of course, you can take these products as is or you can use either as a starter to make El Rotary yogurt to generate even higher counts of microbes for bigger effects. I'll provide a link for these products below in the show notes. So how can we remedy this situation of overexposure to blue light that has consequences that include reduced visual acuity, damage to your lenses of your eyes, damage to the retina and long-term consequences such as increased risk for macular degeneration, the increase in insulin resistance reduction, vagal tone and heart rate variability and perhaps even cognitive decline, deterioration of skin health and adverse effects on mitochondrial generation of energy and mitochondrial health.
William Davis, MD:Well, let's start by reducing your exposure to LEDs by thinking about replacing selected LED lights with old-fashioned incandescent lights. Now, I'm not suggesting you change all your lighting in your house back to incandescent, because that's energy inefficient and there are some real benefits societally to converting to lower energy LEDs. It may save a lot of money, it may reduce the carbon footprint of human life, but you may do what I did, that is, just exchange the LEDs with incandescent bulbs in areas you frequent. For me it's my desk where I work a lot, or maybe for you it's a chair where you like to sit and read, the places where you frequently are exposed to light. Think about replacing LEDs with incandescent, recognize that fluorescent lighting is no better. Most people don't have a lot of fluorescent lights in their home, but they have a lot at work. That's a problem. So if there's some way to restore some incandescent exposure rich in red light reduced in blue so maybe you have your own desk lamp that has an incandescent bulb at your desk at work.
William Davis, MD:Another thing to consider is blue blocking glasses, particularly later in the day, especially after 4 pm. There's two forms that I'm aware of. There's clear blue blocking glass and you can test them by shining them, by holding them up to light, and you should see blue reflected in the lens. That is, it's blocking blue. The clear lenses are pretty good at blocking blue. It's the yellow or orange lenses, however, that are even better at blocking most blue wavelengths. So think about wearing them when you're overexposed to blue. Whether it's at your desk or at your computer with an LED screen, or looking at your smartphone late in the evening or your tablet. Blue blocking glasses can minimize or reduce your exposure to blue, especially important later in the day Because, remember, exposure to blue turns off your brain's production of melatonin and can disrupt your sleep pattern, disrupt the circadian rhythm. So getting rid of blue later in the day can allow your pineal gland to produce melatonin and thereby reassume the normal circadian rhythm.
William Davis, MD:Now, as I mentioned, the flip side of this argument is to not only reduce our exposure to blue, but to also increase our exposure to red and infrared, particularly if you live in a climate where you can't get sunlight. Now I remind everybody that we really can't do much better in the red infrared frequency than getting sunlight. So if you live in Hawaii or Florida or Arizona or other very sunny climate, you probably don't need to worry too much about red exposure and infrared exposure, because you get natural red. You can't do better than natural red. But if you're living in a climate like I do or live a life like I do, where you live a lot of your time indoors, the sun is too weak, it's covered by clouds, it's too cold For me in the last few days it's been zero or below zero. You can't really go outside. Even though red infrared penetrates clothing, the intensity of the radiation is so low. Recall that red infrared experience is heat. If it's really cold, you're not getting that heat.
William Davis, MD:So we'll talk more in future about the benefits and the hype, the over-hyping, of exposure to red and infrared. It is important, but it has been the subject of a lot of profiteering by manufacturers of devices, so we'll talk about all the aspects of red and infrared. In the meantime, think about reducing your exposure to LED blue from all the different sources to take advantage of all the benefits of reducing overexposure to blue and, in future, re-exposure to red infrared. Now, if you learned something from this episode of the Defiant Health Podcast, I invite you to subscribe through your favorite podcast directory. Post a review, post a comment and join this movement of self-empowerment in health. Thanks for listening.
