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Deconstructing Red Light Therapy Intensity: Why MORE Isn’t Always BETTER!
Red Light Therapy Intensity: Why Higher Power Isn’t Always Better for Results “High intensity, medical grade Red Light Therapy”. This is a statement that is often made about Red Light Therapy devices, implying that to see real therapeutic benefits, that a device must be really powerful. But is this actually true? What does the scientific evidence say about high intensity Red Light Therapy devices? Let’s dig into the research. But first, we need to define what light “intensity” is. Light intensity (also known as power density) describes the amount of light being delivered by a device. Also sometimes called irradiance, it’s usually measured in units called mW/cm2. Intensity is related to power, which is the rate at which energy is delivered, measured in Watts (W). If we look at that energy per square cm of exposure site, we get W/cm2, or mW/cm2 – our intensity. So, intensity is the amount of energy from a device at any given moment, and if we consider that as a function of time of exposure, we get the energy density (measured in J/cm2), which is the total energy delivered over time. This combination of intensity with exposure time is also referred to as the “dose” of light delivered by the treatment. Let’s dig into the assumption that higher powered devices are required to derive benefit by exploring five lines of evidence. 1. Where did the idea that high intensity Red Light Therapy is required for therapeutic benefit come from? This idea comes from the fact that for decades, virtually all research and applications of photobiomodulation were done with lasers, which are high intensity devices. Research into Red Light Therapy began in the 1960’s, and lasers dominated the field until around the early 2000’s, when LED’s (light emitting diodes) began to be studied. The scientific literature is comprised of around 85% studies using lasers as light sources, with the rest using LED’s. Companies making higher powered devices are often trying to get close to the power of lasers, citing laser research that shows benefits. However, hundreds of studies have now shown that LED Red Light Therapy yields many benefits, such as reducing pain and inflammation. And, LED’s have four important advantages over lasers: (1) they’re safer, (2) they’re cheaper, (3) they can be easily used at home, and (4) LED’s can cover a greater area of the body allowing more tissue to receive light. Given this, an important question for researchers in the field to address was whether the benefits of Red Light Therapy were specific to something about laser light, or whether those benefits could be replicated using LED’s. In 2018, an analysis that reviewed the comparative evidence of lasers versus LED’s concluded that “most of these comparisons provisionally suggest that lasers could indeed be replaced with LED’s without significant worsening of the results.” This is despite major differences in power outputs, which demonstrates that high intensity lasers are not required for therapeutic benefits. 2. Does the research on Red Light Therapy demonstrate that a certain intensity range is needed to observe therapeutic benefits? There is an excellent comprehensive database online of published photobiomodulation research studies that describes the details of thousands of Red Light Therapy studies. We can look at this database to compare the intensity (power) of studies relative to their results, and to see if there are clear trends, such as a requirement for high intensity/power to yield benefits. Most studies using LED’s have an intensity between 10 and 100mW/cm2 and are most commonly between 10 and 50mW/cm2. For lasers, the intensity is much higher, based on the different characteristics of the light produced. Positive results spanning a wide range of outcomes are observed, and there are no clear trends related to light intensity. Some studies use extremely low intensity LED lights, some use higher intensity LED lights, and some use high intensity lasers. Although studies of certain light intensities are sometimes used to support specific products, when you look at the totality of the research, the main conclusion that can be drawn is that exposure to red and/or near infrared light across a wide range of light characteristics, including intensity, yields biological benefits. 3. Can devices with different intensities be used to deliver the same “dose” of light? Theoretically, the time variable can be manipulated when using devices with different intensities to deliver the same “dose” of light. Mathematical calculations show that higher intensity devices used for shorter periods of time can deliver a comparable dose of light to lower intensity devices used for longer periods of time. However, some research has demonstrated that our bodies don’t seem to absorb photons the same way when they are delivered at a high intensity, suggesting that “dose” may not simply be a mathematical calculation of intensity and time. For example, a recent comprehensive review of studies of red light therapy for the brain found that “NIR light with low-power density (15–30 mW/cm2) is a more effective intervention than that with high-power density (40–90 mW/cm2)." 4. If low, moderate, and high intensity devices have been shown to deliver therapeutic benefits, are there reasons for preferring low or moderate intensity rather than high? Yes, there are reasons to prefer low to moderate intensity devices as compared to high. For example, high intensity light can increase oxidative stress, which is harmful to biological health. When wounds are treated with low/moderate intensity red light therapy, markers of oxidative stress initially increase and then decrease dramatically as healing progresses. However, when wounds are treated with high intensity red light therapy, oxidative stress remains high. Similarly, levels of antioxidant enzyme activity (which reduces oxidative stress) increase with low/moderate intensity red light therapy but not with high intensity light. This suggests that low/moderate intensity Red Light Therapy reduces oxidative stress, while high intensity Red Light Therapy may cause it to increase. High intensity light also carries a risk of heating tissues and causing thermal damage. 5. Are there biological reasons to expect that there could be an upper limit to Red Light Therapy intensity when it comes to therapeutic benefits? Yes! Researchers have carefully studied the biological effects of Red Light Therapy and have clearly concluded that “dose” matters. If the dose is too low, there is no benefit; similarly, if it is too high, there is also no benefit – and there is the potential for harm. This is called a biphasic dose response, also known as the Arndt Shulz law. Picture this as an inverted U curve. If the dose is too low or too high, there will be minimal response, but there is a relatively wide range of doses in the middle range that are beneficial. As described by Dr. Michael Hamblin, “It has been consistently found that when the dose of is increased a maximum response is reached at some value, and if the dose in increased beyond that maximal value, the response diminishes, disappears and it is even possible that negative or inhibitory effects are produced at very high fluences.” Because “dose” is a function of intensity and time, using high intensity devices for too long can easily yield a dose of light that will not be beneficial, and may even be harmful. These five lines of evidence clearly illustrate that the assumption that high intensity devices are needed to achieve benefit is not accurate. It is the dose that creates the benefit – and dose is a function of intensity and time. While it may be appealing to use a higher intensity light to get the treatment done faster, this carries risks including thermal damage due to heating tissues, as well as a risk of causing oxidative stress. The tendency when using a high intensity device – which would require a treatment time of only a few minutes (or even less) – is to overdo it. For at-home devices, low to moderate intensities leave more wiggle room in terms of both safety and benefits. Fringe Red Light Therapy Intensity Fringe Red Light Therapy products were designed to deliver light at an intensity of 20-40mW/cm2, which is the approximate intensity of the sun. This has been described as the “sweet spot” between higher intensities, which can have harmful effects, and lower intensities, which will have no effect at all. Although there are no clear distinctions between low, moderate, and high intensity devices, the intensity of Fringe Red Light Therapy devices would most appropriately be termed as low/moderate and stands in contrast to many devices on the market, which are 100mW/cm2 or even higher. At this intensity, our products can safely be used for treatment periods between 10 and 30 minutes, and our products are programmed with built-in timers to deliver a safe and effective dose of light. We verify the intensity of our products using third party testing, which is important because independent research has found that many commercial home-based Red Light Therapy products do not deliver light as advertised. Take Home Points The idea that high intensity Red Light Therapy devices are needed for therapeutic benefits originated from decades of research using high intensity lasers; however, subsequent research has demonstrated that lower intensity LED powered devices can yield comparable results. An analysis of the totality of published Red Light Therapy research (using both lasers and LED’s) shows that benefits can be seen when using devices that span a very wide range of intensity, from low to high. This is consistent with research that shows the effective “dose” of Red Light Therapy follows a U-shaped curve, with benefits spanning a wide range but which has a lower and upper limit. The “dose” of light is determined by its intensity and the treatment time, although research has shown that delivering light quickly using a high intensity device may not be as effective as delivering it more slowly using a lower intensity device, suggesting that the “dose” is not the only factor that determines benefits. High intensity light can increase oxidative stress and the risk of thermal damage, so care must be taken when using high powered devices to limit treatment times, which can be difficult to do when using at-home devices. The Verdict? Research evidence does not support the claim that high intensity Red Light Therapy devices are required for therapeutic benefits. Using low to moderate intensity devices yields results that are comparable to using high intensity devices, with some research even demonstrating greater efficacy. Low to moderate intensity devices also have the advantage of greater safety and can be safely used at home as part of a regular wellness regime. Choose a device that suits your needs and preferred treatment conditions, and which delivers both red and near infrared light at an appropriate intensity. Combine red light therapy with an anti-inflammatory diet and supplements, regular exercise, stress management, and good sleep hygiene for best results.
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Light Therapy & Menopause
Menopause Menopause is the natural transition that occurs when a woman stops menstruating, which usually happens between the ages of 40 and 58. The term “transition” refers to a change from one state to another, which is a very apt descriptor for what happens during menopause. Hormonally speaking, menopause marks a shift to an entirely new hormonal milieu, which not surprisingly, can be quite challenging. Hormonal Changes During Menopause The hormonal changes that accompany menopause are dramatic. From perimenopause (the stage leading up to menopause) to post-menopause (the stage following menopause), levels of estrogen and progesterone drop to a fraction of their previous levels. This sharp decline is not linear, instead showing fluctuations that can create a whirlwind of physical and psychological symptoms. Levels of testosterone also decrease during this transition. The effects of menopause The effects of menopause on the brain and body are similarly dramatic. Although these vary widely between individuals, there are many common symptoms, including hot flashes, loss of libido, vaginal dryness, sleep issues, weight gain, dry skin, hair thinning, digestive changes, sexual dysfunction, urinary symptoms (including incontinence) and mood disturbances. Some menopausal symptoms are local, occurring mainly in the pelvic region, while others (such as hot flashes) are felt throughout the body. Similarly, some symptoms are transient while others cause persistent and long-term physical changes. The experience of menopausal symptoms is extremely common. Overall, it is estimated that 75-80% of women suffer from symptoms related to menopause, of which 20-30% are considered severe. Approximately 75% of women worldwide experience hot flashes, while 40-60% suffer from sleep issues. As many as 83% of women report experiencing vaginal dryness, often with associated pain during intercourse. Research has found that 9 in 10 women weren’t educated about menopause, and since talking about these symptoms has long been viewed as “taboo”, women often suffer menopause symptoms in silence, leaving them unable to access tools that might help to alleviate them. Improving access to supportive tools during menopause is a critical public health issue. This includes natural and alternative therapies, as well as novel tools such as light therapy. Light - including red, near infrared, and blue light – may help to alleviate several of the challenging symptoms of menopause, including sleep and mood issues, vaginal dryness and atrophy, hair loss, overactive bladder, sexual dysfunction, cognitive and digestive changes, and skin problems. Read on to learn how light therapy can be used to support women’s health during this important transitional period. Light therapy Before we can explore how light therapy can be used to support women’s health during menopause, we first need to answer the question: what is light therapy? The answer is really quite simple. Light therapy (also known as photobiomodulation) is the application of light with specific wavelengths to the body for the purposes of influencing biology. In theory, light therapy can use any wavelength of light, but the most commonly used are red, near infrared, and blue. The use of red and near infrared light is commonly referred to as “red light therapy”. All three wavelengths of light may be useful in supporting women during menopause, although red and near infrared light have the greatest utility. Research has shown that light therapy has many effects on a cellular level. Briefly, with red and/or near infrared light, the most notable observed effects include an increased production of cellular energy, reduced inflammation, decreased oxidative stress, decreased pain, increased blood flow, enhanced collagen and supportive tissue production, and improved microbiome health (gut and vagina). Blue light is mainly used to destroy pathogenic microorganisms like yeast and bacteria. Light Therapy & Menopause Given that there is such a wide range of menopausal symptoms (note that for simplicity, symptoms related to peri-, meno- and post-menopause are being considered here as “menopausal” symptoms), it is likely that the various physiological effects of light therapy will be more or less relevant for certain ones. For example, some of the changes seen during menopause – such as vaginal atrophy, dryness, and urinary incontinence - are due in part to a decrease in blood flow and loss of connective tissue in the pelvis. While specific research into using light therapy to treat these symptoms is still sparce, researchers have proposed that based on existing scientific evidence, red light therapy may alleviate these symptoms by stimulating the production of collagen and elastin, supporting bladder function, and enhancing blood flow. Many symptoms of menopause are also experienced in other states, and we can look to those conditions for clues regarding how to use light therapy to alleviate the same symptoms during menopause. This includes anxiety and depression, hair loss, sleep disturbances, acne, digestive issues, and infections. While research specific to these symptoms in menopausal women is lacking, there is clear evidence that light therapy (with red, near infrared, and/or blue light) can be helpful in other conditions, and we can extrapolate from there to the menopausal state. Based on the known physiological effects of light therapy, and the evidence of benefits in a range of clinical conditions, we propose that the use of red, near infrared, and/or blue light may help to alleviate several of the most common symptoms experienced by women during this life transition, including: Mood: Mood changes are a common experience during menopause, with many women reporting increases in anxiety and depression. Light therapy (with red and near infrared light) has been shown to reduce depressive symptoms in both humans and animals, likely due to improvements in mitochondrial function, increased brain blood flow, and decreased neuroinflammation. A 2009 clinical trial found a reduction in symptoms of depression and anxiety in as little as a single session. The effects of light therapy on mental health are so compelling that a recent systematic review concluded that it is “strongly recommended” as a treatment for moderate depressive disorder and is “recommended” for the treatment of anxiety disorder. Studies of red light therapy and depression often apply light therapy directly to the skull, while some use an intranasal approach. Cognition: Cognitive changes, such as memory loss, are also commonly experienced by women during menopause. Researchers have shown in a series of controlled clinical studies that near infrared light therapy improves cognition in young and middle-aged healthy adults when applied to the prefrontal cortex of the brain. Cognitive improvements were accompanied by changes in brain function, including increased brain blood flow. In 2019, a meta-analysis of all the research looking at the effects of light therapy (including near infrared light, or near infrared and red light in combination) found that the overall effect on cognition was positive, leading the authors to conclude that light therapy is a “cognitive-enhancing intervention in healthy individuals”. Hair Loss: Menopausal women frequently report hair loss and thinning. The ability of light therapy to induce hair growth was observed in studies conducted more than 50 years ago. Early clinical trials used primarily red light, and the effectiveness of these studies led to the development of several red light therapy devices for hair loss. Subsequent studies have shown that near infrared light also stimulates hair growth, with red and near infrared light improving hair growth in androgenetic alopecia, which is the most common type of hair loss that affects both men and women. Light impacts hair growth through effects on mitochondria, which lead to increases in the length of time the hair follicle spends in the growth phase. Overactive Bladder: Overactive bladder, involving a frequent urge to urinate, is a urinary symptom experienced during menopause. Overactive bladder often results in urinary incontinence. Although research related to light therapy and overactive bladder is limited, one study found that application of red light to the abdomen three times per day for 12 weeks resulted in a reduction of urinary incontinence as compared to a control group, suggesting a potential benefit in this condition. Skin Changes: During menopause, many women report skin changes, including acne, dryness, altered pigmentation and wrinkles. Light therapy has been widely used in spas and dermatology clinics for its effects on skin health, in addition to at-home use. Red and near infrared light is helpful in the treatment of wrinkles, psoriasis, acne, hyperpigmentation, and rosacea, while blue light is helpful in the treatment of acne. Studies show results such as smoother skin; wrinkle reduction and improved skin elasticity; and normalization of skin pigmentation. The effect of red light therapy on wrinkles can be quite dramatic, with one study showing a 30% decrease in eye wrinkle volume. Gut: Gut dysbiosis, involving changes in the gut microbiome, are common around the time of menopause. Estrogen is known to affect the gut microbiome and similarly, some of the microbes in the gut microbiome (called the estrobalome) are able to influence levels of estrogen in the body. Keeping the microbiome healthy during menopause is essential, and light therapy (with red and near infrared light) may provide some support. Animal research has shown that when red or near infrared light was applied to the abdomen of mice, the composition of the microbiome shifted to include more of a bacterial strain that is associated with better health. In humans, red and near infrared light applied to the abdomen of Parkinson’s disease patients modulated the composition of the gut microbiome, with a shift towards more “healthy” bacteria, and in a case report of a patient with breast cancer, application of near infrared light to the abdomen was associated with increased diversity of gut microbes, which is considered to be a healthy change Vaginal Dysbiosis: Similar to the gut, the vagina has a microbiome, and menopause can cause dysbiosis in this region as well. Hormone-induced dysbiosis can increase the vaginal pH and change the composition of the microbes, which is associated with bladder dysfunction and bladder pain syndrome. Light therapy, particularly with red and near infrared light, is proposed as being a positive modulator of the vaginal microbiome. There are several proposed mechanisms, including modulation of nitric oxide. Nitric oxide is important for the lactobacillus species that dominate in the vagina that are known to decrease during menopause. Sleep: As already mentioned, sleep disturbances are experienced by 40-60% of menopausal women. Light is a primary regulator of the body’s circadian rhythm, so it is not surprising that light therapy has effects on sleep. Application of red and near infrared light during wakefulness improves sleep quality in people with cognitive decline, Guillain-Barré Syndrome, fibromyalgia and stroke. When red light therapy is applied during sleep, there is an increased clearance of waste products from the brain and improved flow of cerebrospinal fluid, which are required for optimal brain health. Blue light triggers wakefulness, suppressing melatonin, so direct exposure of the eyes to blue light should be limited to daytime hours. Vaginal Infections: Vaginal infections with yeast and bacteria are more common during menopause due to the changes in estrogen, vaginal pH, and vaginal dryness that occur. In addition to their positive effects on the microbes in the gut and vagina, red and near infrared light have also been shown to have effects on pathogenic (harmful) microorganisms in the female pelvis. Red light has been shown to be helpful in treating vaginal candida, as has blue light. Specifically, blue light at 415nm (the same wavelength as in the Fringe Pelvic Wand) had the most potent anti-candida effects. Blue light has also been shown to be helpful in the treatment of vulvovaginitis. Vaginal Atrophy: Vaginal Atrophy, Dryness & Sexual Dysfunction: The loss of estrogen during menopause causes many changes to the integrity of tissues in the vagina. This results in tissue atrophy and dryness, which can cause great discomfort, especially during sex. The main structural connective tissues are collagen and elastin, which provide strength and flexibility to the vagina. These changes occur for a variety of reasons, including a decrease in blood flow which results from the loss of estrogen. Application of red and near infrared light is known to increase blood flow by increasing levels of nitric oxide. It has also been shown to increase the synthesis of collagen and other supportive connective tissue including elastin. Suggesting that red and near infrared light may help with tissue support and rejuvenation during menopause. Light Therapy Products for Menopause While early research on light therapy used primarily lasers, more recent research has found that LED’s can also be used, which also have the advantage of applying light to a larger area of the body as well as an improved safety profile. The use of LED in red/near infrared/blue light therapy devices has also greatly reduced the cost of treatment, making it something that can be done in the comfort of one’s own home. A wide range of products are available, each of which is uniquely suited to address specific needs. The four most useful light therapy products to address the symptoms of menopause are: Red light therapy panel Panels usually deliver red and near infrared light, ideally with the option to use separately or in combination. Panels can be used to treat most body parts, including the face, chest and back. They’re great for supporting sleep and mood, when light should be entering through the eyes. They can also support digestion when directed towards the skin of the abdomen, as well as the skin on the face. The Fringe Red Light Therapy Panel delivers both wavelengths of light at the same “sweet spot” intensity as the sun. shop our panel Red light therapy wraps Red Light Therapy Wraps deliver light directly to the skin and can be applied to specific body parts, such as the head and abdomen. They should also deliver both red and near infrared light. Wraps have the advantage of being cordless and very convenient to use. The Fringe Red Light Therapy Head Wrap delivers light to the head (including red and two wavelengths of near infrared light) and is ideally suited to support mood, cognition, and hair loss. The Fringe Red Light Therapy Wrap has a rectangular shape and can be applied to the abdomen to support bladder function and digestion. shop our wraps Light therapy face mask Like wraps, face masks deliver light directly to the skin but are specifically contoured to the face. Due to the antimicrobial effects of blue light, it should be included in face masks for the treatment of acne along with red and near infrared light. The Fringe Red Light Therapy Face Mask delivers all three wavelengths of light to support skin health, including acne, wrinkles, pigmentation, and more. shop the mask Light therapy pelvic wand Light therapy pelvic wands are inserted directly into the vagina, delivering light directly to the vaginal tissues that are affected by menopausal hormonal changes. The Fringe Light Therapy Wand delivers red, near infrared, and/or blue light to support blood flow and tissue rejuvenation, which may help alleviate vaginal dryness, atrophy, and sexual dysfunction. shop the wand To recap Menopause is a time of dramatic hormonal changes, which create uncomfortable symptoms for many women. Light therapy is a safe and effective tool that may be used to alleviate a wide range of menopausal symptoms in the comfort of one’s own home. Red and near infrared light provide support for symptoms including sleep and mood issues, cognitive changes, hair loss, gut and vaginal dysbiosis, skin problems, and vaginal tissue changes, while blue light may provide antimicrobial activity for menopausal acne and vaginal infections. Many different light therapy products are available - including panels, wraps, face masks, and pelvic wands – that provide light therapy support for different symptoms. Choose products that use LED lights to deliver red, infrared red, and blue light (where appropriate) at approximately the same intensity of the sun for best results. For more information about Fringe light products, go to: https://fringeheals.com/shop-all-products/
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Red Light Therapy for Gut Health
The Human Gut The human gut, also known as the gastrointestinal tract (GI tract), consists of the esophagus, stomach, small intestine, and large intestine. In simple terms, it is a tube or passageway for food that passes from the mouth to the anus. Each part of the gut has its own job to do, which is usually described as the digestion and absorption of food, and the excretion of digestive waste products. In recent years, however, a critical new role has emerged for the human gut, specifically the large intestine. As the last part of the GI tract, the large intestine receives food after most of the nutrients are absorbed and functions to reabsorb water and some remaining minerals. While this final step in the processing of food is essential, equally (if not more) important is the role of the large intestine as host to the gut microbiome, which is being described as a “major determinant of health.” The Gut Microbiome The human body contains over 150 times more genes from resident microorganisms (such as bacteria, viruses, and fungi) than from its own human cells. With a total weight of just over 2kg, microbial cells outnumber human cells by around 10 to 1. Most of these organisms went unrecognized until the last two decades. However, we now know that the body is literally teeming with invisible inhabitants, which comprise what is referred to as the human microbiome. The combined human and microbiome genome is referred to as the “holobiome”. The term “resident” is an apt descriptor when it comes to the microbiome. These organisms live inside the body, from birth to death. They also reside on the surface of the skin. And while the germ theory of disease has conditioned us to believe that most microorganisms are pathological, in fact the human microbiome is one of the most important biological predictors of health. The opposite is also true: alteration in the microbiome is an important predictor of disease. The microbiome communicates with the body, and the body communicates with the microbiome. This crosstalk is essential for human health. The human microbiome can be broken down into several divisions, based on location. The microbiome that lines the mouth is the oral microbiome; the microbiome that lines the skin is the cutaneous microbiome; the microbiome that lines the vagina is the vaginal microbiome; and the microbiome that lines the digestive tract is the gut microbiome. The gut microbiome is the most well researched biome. The role of the gut microbiome is complex and spans a wide range of diverse functions. Gut microbes are involved in the metabolism of carbohydrates, lipids, and proteins, and help to extract nutrients from food. In the gut, they produce useful molecules such as short chain fatty acids and vitamin K. Gut microbes also manufacture neurotransmitters such as serotonin, and through the gut brain axis, regulate many aspects of cognitive function. The microbiome is also involved in the metabolism of ingested drugs and toxins. The gut microbiome starts its development in utero and continues throughout the fetal period, with further colonization during delivery. Most gut microbes are acquired post partem, with breast milk as an important source in early life. A diet containing predominantly plants and whole foods is considered optimal to support the gut microbiome, with fiber being of utmost importance. Processed food, food that is high in sugar, and low fiber diets are bad for gut health. It has been recommended that dietary guidelines be revised to support a healthy gut microbiome. In addition to diet, there are several other factors that influence the health of the gut microbiome. According to the Canadian Digestive Health Association, non-dietary ways to strengthen the microbiome including: avoiding antibiotics, regularly sleeping for at least 8 hours per night, getting regular exercise, and engaging in stress reducing activities. Evidence is also accumulating that gut microbiome health can be supported by therapy with red and near infrared light. Light Therapy Light therapy (also known as photobiomodulation) is the application of light with specific wavelengths to the body for the purposes of influencing biology. The most common form of light therapy uses red light (RL), which is visible as the color red, and/or near infrared light (NIRL), which is not visible but can be felt as heat. The RL used in light therapy usually ranges from 600 to 700 nanometres (nm), with the unit nm referring to distance the light wave travels in one cycle. The NIRL used in light therapy usually ranges from 800 to 900nm. RL and NIRL are naturally produced by the sun, which gives off solar radiation. The term radiation describes energy that is transmitted in the form of waves or particles. The spectrum of light in our environment consists of both light we can see (visible light) and light that our eyes can’t perceive (invisible light). This is called the electromagnetic spectrum. The visible light spectrum is quite narrow, consisting of wavelengths that range from 400 to 700nm and span from violet to red in color. RL is part of this visible light spectrum, while NIRL is not. Red and near infrared light therapy is the application of artificially generated light in the red and near infrared spectral bands. The term “red light therapy” usually describes the use of both RL and NIRL, although only the red light produced by the device is visible to the naked eye. IRL can still be perceived by the body as heat when it contacts skin. How Does Red Light Therapy Affect Gut Health? Red light can affect gut health both through effects on the microbes in the microbiome, as well as on the gut cells of the human host. It’s hard to tease out precisely what is happening in this complex microenvironment, but one thing is clear: light therapy administered to the gut has a positive biological effect. Research has indeed shown that light can modify the microbiome. For example, when RL or NIRL was applied to the abdomen of mice, the composition of the microbiome shifted to include more of a bacterial strain that is associated with better health. Bacteria have also been found to respond to the direct application of RL. Light therapy also impacts human cells. Light is absorbed in cells by molecules called chromophores, many of which are found inside the mitochondria. Mitochondria are the powerhouses of the cell, which make the energy currency of the cell known as ATP. Mitochondria are also involved in regulating the production of molecules called reactive oxygen species (ROS), which play a role in normal cellular function but can be harmful in high amounts. This is known as oxidative stress. Through its effects on mitochondria, light therapy can increase cellular energy production and modulate oxidative stress. Intestinal oxidative stress is associated with disease. Through effects on cellular metabolism and ROS production, as well as through reduction of other molecules such as reactive nitrogen species and prostaglandins, light therapy can decrease inflammation. Both RL and NIRL have anti-inflammatory effects, and unlike anti-inflammatory medications (such as NSAID’s), do not cause side effects. Inflammation is a hallmark of many gut disorders, such as Crohn’s Disease and Ulcerative Colitis. By improving the health of the gut (both the microbiome and human gut cells), a wide range of positive effects are observed, including: Improving communication between microbiome and the rest of the body. Improving digestion of food and production of energy and nutrients. Decreasing inflammation and production of reactive oxygen species. Increasing production of short chain fatty acids involved in immune function. Improving the health of the gut lining. Gut Dysbiosis When the gut microbiome is dysregulated, there is an adverse effect on its human host. This is called gut dysbiosis. Poor dietary choices, sedentary lifestyle, increased stress, and use of antibiotics (and other pharmaceuticals) can cause the gut microbiome to become unhealthy. This causes a loss of integrity of the gut lining, also known as leaky gut. In turn, the gut becomes permeable to things like microbes and food fragments, which activate the immune system and trigger an inflammatory response. Chronic inflammation ensues, and a vicious cycle is established in which the gut becomes increasingly compromised, which worsens the inflammation. Dysbiosis also impairs metabolism. Gut dysbiosis has been associated with an enormous range of human disease, including metabolic syndrome, neurological disorders, immune system disorders, autism, psychiatric disorders, obesity, systemic inflammation/autoimmunity, type 2 diabetes, chronic pain, multiple sclerosis, inflammatory bowel disease, and eye diseases. A 2021 article in The Guardian described that “The great opportunity – but also the great difficulty – of gut microbiome science is that poor gut health is associated with such a vast range of conditions.” This means that there is enormous potential to reduce human disease by improving the health of the gut microbiome, although it is important to acknowledge that our understanding of these relationships is still limited. Clinical Applications of Light Therapy to the Gut The use of light to improve health dates back thousands of years. Sunlight has been used in medicine since at least the time of the Ancient Greeks, to treat conditions such as tuberculosis, skin disorders, and bacterial and fungal infections. However, the practice fell out of favor during the 20th century as modern societies embraced the medical pharmaceutical model of therapeutics. Over the last decade, there has been an increasing interest in harnessing the power of light as a therapeutic, and a wide range of applications are being explored. Several studies have investigated what happens when RL and/or NIRL light is applied to the abdomen. Interestingly, the bulk of this research has been done using abdominally applied light to treat brain disorders, rather than for GI tract diseases. This is because of the important relationship between the gut microbiome and the brain, through a pathway known as the gut-brain axis (GBA), which involves bidirectional communication between the gut (including the microbiome) and the brain. The GBA plays an important role in brain, gut, and immune health. Alterations in the gut microbiome may be associated with disease through the GBA. RL and NIRL applied to the abdomen (as well as the neck, head and nose) of Parkinson’s disease (PD) patients has been shown to modulate the composition of the gut microbiome, with a shift towards more “healthy” bacteria. Light applied to the abdomen and neck for 12 weeks also decreased symptoms such as impaired mobility in PD patients, with improvements lasting for up to a year. PD is a degenerative brain disease that causes motor symptoms (such as balance and gait problems) and non-motor symptoms (such as depression, sleep disorders, and cognitive impairment). It affects around one million people in the US, and over 10 million people globally. Application of RL and NIRL to the abdomen (as well as the head) has also been used in the treatment of Alzheimer’s Disease (AD). In a 2022 clinical trial of patients with mild to moderate AD, those receiving light therapy showed improved cognitive function relative to the control group. Alzheimer’s Disease (AD), a form of dementia, is a neurodegenerative disease that comprises 70% of dementia cases. AD affects 1 in 10 US adults over the age of 65, or 5.7 million Americans. It has been suggested that light therapy applied to the abdomen may be useful in reducing depression. The composition of the gut microbiome has been linked to depression, with depressive patients showing higher levels of certain bacteria that are involved in the synthesis of neurotransmitters such as serotonin and GABA. These neurotransmitters are involved in the regulation of mood. Gut microbiome composition has been strongly associated with mental well-being. Given the associations between brain diseases and the GBA, it has been suggested that targeting the microbiome holds great potential in the treatment of neurodevelopmental and neurodevelopmental diseases. In addition to AD and PD, these include diseases such as multiple sclerosis, autism spectrum disorder, attention-deficit hyperactivity disorder, migraine, post-operative cognitive dysfunction, and long COVID. According to researchers from Australia, many studies are currently underway “with the aim of restoring the microbiome and potentially altering the course of these brain conditions.” Light therapy may also be helpful in modifying the microbiome in diseases that primarily affect other body systems. For example, in a case report of a patient with breast cancer, application of NIRL to the abdomen was associated with increased diversity of gut microbes, which is considered to be a healthy change. The authors suggest that light therapy may be a way to improve gut health in patients with chronic disease. Most patients with chronic disease use medications which may adversely affect gut health (especially the microbiome). There is also great potential to use light therapy to treat gut disorders. For example, animal research has found that application of RL to the abdomen of rats with experimentally induced colitis (a form of inflammatory bowel disease) improved many markers of gut health, including reducing inflammation. There is interest in studying the use of light therapy to improve gut health in human subjects as well. Notably, a study using NIRL applied to the abdomen (as well as the front of both thighs) is currently underway to assess whether treatment reduces pain, fatigue, and depression in patients with inflammatory bowel disease. Effects on the gut microbiome will also be measured. Using Light Therapy for Gut Health There are many light therapy devices on the market today that could be used at home to target gut health. With so many options available, how can you know which device is best for you? Here are five issues to consider. Style Preference: To treat the gut with light therapy, light should be applied to the abdominal area. Two types of devices are most appropriate for abdominal applications: (i) a light panel, or (ii) a light wrap. Your personal level of comfort with a device is important. Imagine yourself using it – Do you want to stand in front of the device, or would you prefer the flexibility of being able to lie down while wearing it? Do you want a device that is wireless, or can you commit to being close to an electrical outlet so that you can plug it in? Think about your personal preferences and choose accordingly. Laser vs LED: Light therapy is administered using either laser or LED lights. While early light therapy research was done using lasers, LED lights have become much more popular over the last decade. The research described in this article includes both types of light sources. In 2018, Dr. Michael Hamblin – the world’s leading light therapy expert – concluded that LED lights using comparable parameters to lasers performed “equally well”, which is very important because LED powered light therapy devices can be made at a fraction of the cost of laser devices. For at home use, look for a device that uses LED lights as safe and affordable option. Light Color/Wavelength – As described in this article, both RL and NIRL have been used in studies of light therapy to treat gut disorders. Positive results have been observed when these wavelengths were used either together or individually. So, look for products that use RL and NIRL either alone or in combination. Light Intensity – Light intensity refers to the amount of light being delivered by a device. It is also referred to as irradiance. The required intensity when using light therapy to impact gut disorders is unclear. There is variability in light intensity between studies, and no studies have directly compared different intensities. Since light is being delivered to the skin of the abdomen, it may be prudent to follow the advice given for light therapy to the skin, and mimic the intensity of the sun, which is around 24 mW/cm2. This is described as the “sweet spot” between higher intensities, which can have harmful effects, and lower intensities, which will have no effect at all. Placing a high intensity device directly on the skin could be harmful. Choose a sun-mimicking product and don’t overdo it when it comes to treatment frequency and duration. Education – While light therapy education will not change the specific functionality of a device, it does have the potential to profoundly impact how someone uses the technology. When a company provides evidence-based education that teaches consumers why, how, and when to use a product, devices can be used to better support healing. Look for products with accompanying education and instructions for use, whether in printed and/or digital formats. You can also look for companies that provide support by phone or email to current or prospective customers. Conclusion Hippocrates is credited with stating that “All disease begins in the gut”. While today’s science does not yet support that level of conviction, we do know that gut health is intimately associated with the overall health of the human body. We also know that “what happens in the gut doesn’t stay in the gut”, but rather influences other organs and systems through complex communication networks. The gut microbiome is inextricable from our own human gut, and both are important for optimal health. When using light therapy for gut health, it’s important to also engage in other gut-friendly activities. These include eating a gut healthy diet, staying hydrated, exercising regularly, and limiting stress. It’s advisable to work with a health care provider with expertise in this area and who can provide appropriate support. Many questions remain about how light therapy can be used to support gut health, but preliminary pre-clinical and clinical evidence supports the use of RL and NIRL both to induce healthy shifts in the gut microbiome and to decrease inflammation. Since RL and NIRL also have other effects, such as increasing energy and decreasing ROS production, many other benefits are likely to be observed. This is certain to be an area of active research interest, especially given the amazing safety profile of light therapy and the increasing availability of at-home devices. For more information about Fringe light products, go to: https://fringeheals.com/shop-all-products/
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