Parkinson’s disease: from the gut to the brain. Infrared light may improve the gut’s microbiome

Margaret Jarrett was diagnosed with Parkinson’s disease 8 years ago. And although she was bothered by many of the symptoms that commonly afflict Parkinson’s sufferers – resting tremor, uncertain gait and terrible nightmares – one thing that bothered her the most was her loss of the sense of smell.

An avid gardener, she took great pride in her rosarium, but being unable to inhale their perfumed scent, really got her down.

“You take something like your sense of smell for granted,” Jarrett, 72, said. “You don’t realise how precious something is until it’s gone.”

Parkinson’s disease is a combination of movement disorders including resting tremor, muscle rigidity, impaired balance and slowness of movement. It can also cause neurological problems such as depression, insomnia, memory loss and confusion.

Its cause is unknown but it is associated with dopamine depletion and destruction of neurons in the basal ganglia region of the brain.  

The current mainstay of treatment for Parkinson’s disease involves physical therapy as well as medications which act to increase dopamine levels in the brain. One relatively new avenue of potential treatment for Parkinson’s disease is exposure to infrared light therapy.

In 2017 I wrote an article that was published in The Weekend Australian Magazine titled “Let there be light” about a group of patients in Tasmania who were trialling infrared light therapy for their Parkinson’s disease.

Retired federal politician Max Burr wearing his homemade light helmet in his home in Tasmania

The response was overwhelming, with scores of people contacting myself, the newspaper and researchers named in the article, to request further information on this novel treatment.   

One person whose interest was piqued happened to be Olivia Nassaris, the CEO of Parkinson’s South Australia. “When the article was released, it created this massive buzz and I had so many members of my community wanting more information about it,” she told me.

Nassaris contacted Dr Ann Liebert, co-ordinator of photomolecular research at the Australasian Research Institute, Sydney, who informed her of an upcoming planned trial on infrared light therapy for Parkinson’s disease.  

Dr Ann Liebert with one of her patients at her laser physiotherapy practice in Sydney

Nassaris subsequently persuaded the board of Parkinson’s South Australia to partially fund the trial, on the understanding that at least some of the participants would be from South Australia.      

In addition to assessing the effectiveness of infrared light therapy for Parkinson’s disease, Liebert also wished to see if exposure to infrared light could modulate the gastrointestinal tract’s microbiome in humans.

The gut’s microbiome — composing the trillions of bacteria, fungi and protozoa from hundreds of different species that normally inhabit our gastrointestinal tract — has come under increasing scientific attention over the past decade with links being established between the microbiome and a number of conditions including obesity, Type 2 diabetes, cardiovascular disease and depression.

Photo credit: National Human Genome Research Institute

Several studies have also observed that the gut microbiome is markedly altered in patients with Parkinson’s disease and that faecal microbiota transplantation can have a protective effect in animal models of Parkinson’s.

The reason for this is unknown; however, an interesting observation is that another common pathology seen in Parkinson’s disease is the accumulation of misfolded α-synuclein proteins, called Lewy bodies, in the brain.

It has been shown that certain sensory cells of the gut contain α-synuclein. Researchers have hypothesised that it is possible that abnormal forms of the α-synuclein protein could travel from the gut to the brain through the vagus nerve, a phenomenon that has been shown in animal models of Parkinson’s. Further support for this theory comes from findings that people who have had a surgical vagotomy — where branches of the nerve are cut — have a lower lifetime risk of developing Parkinson’s.      

“We know that infrared light can reduce Parkinson’s symptoms and offer protection to brain cells. So, we wanted to test if it could modulate the gut’s microbiome as well,” Liebert said.

One of the principal researchers in Liebert’s planned study, Dr Daniel Johnstone, scientist and lecturer at The University of Sydney’s Bosch Institute, had previously undertaken a study showing that exposure to infrared light altered the gut microbiome in mice.

“One possibility might be that we’re somehow influencing the microbes in the gut, and that’s having an effect on the brain,” Johnstone said.

Based on the mouse study findings, Liebert and Dr Brian Bicknell, Honorary Fellow in the Faculty of Health Sciences at the Australian Catholic University, conducted a case study last year that showed that infrared light could modulate the human microbiome as well.

In the study a subject received infrared light therapy to the abdomen three times a week for 12 weeks. Faecal sampling showed an increase, after therapy, of some bacteria that are considered beneficial to the gastrointestinal tract including Akkermansia muciniphila, Bifidobacterium and Faecalibacterium.

Liebert wished to see if this finding could be replicated in patients with Parkinson’s and a dozen participants each, from Sydney and Adelaide, were selected, including Jarrett.

Provisional results, from the first half dozen Adelaide participants to have their gut microbiome analysed before treatment and 12 weeks after treatment began, have been promising.

“The six patients that have been put through a similar protocol as the mice showed an increase by up to 20 per cent in the favourable microbiome which is associated with obesity reduction and short chain fatty acid production, and the bacteria associated with rheumatoid arthritis, Crohn’s disease and insulin resistance were all decreased,” Cardiac Health Institute medical director and Professor of Cardiology at Macquarie University, Hosen Kiat, who oversaw the trial, told me.

Cardiac Health Institute medical director Professor Hosen Kiat

Jarrett regained her sense of smell.

“For the last three years I haven’t been able to smell flowers,” Jarrett said. “But several weeks into the trial I started to smell my roses, daphnes and gardenias again and it was wonderful.”

Another participant, Barry Weldon, 70, had a similar experience. “My sense of smell improved significantly” he said. “One day I walked into the house and for the first time in a long time I could actually smell the soup my wife was cooking.”

Ron Till, 68, had an even more dramatic improvement.

“The trial gave me the ability to sleep again,” he said. “It was amazing.”   

Till’s neurologist cautioned him not to get his hopes up before the trial but changed his mind when he saw the results. “He told me it was voodoo medicine and probably wouldn’t work,” Till said. “But after the trial I went back for my three-monthly assessment with him, and he said to me, ‘You’re actually testing better than when you first started with me ten years ago’.”

Retired geologist Sean Kennedy, 76, also experienced an improvement in his co-ordination and balance. “My juggling skills have improved,” he said.   

In a review published in Photobiomodulation, Photomedicine, and Laser Surgery, titled “Photobiomics: Can Light, Including Photobiomodulation, Alter the Microbiome?” Liebert and her co-authors acknowledge that while the exact mechanism by which light therapy alters the microbiome is unknown there is definite potential in light therapy.

“The ability of PBM [light therapy] to influence the microbiome (if proven to be applicable to humans) will allow an additional therapeutic route to target multiple diseases, including cardiovascular disease and Parkinson’s disease, many of which have thus far eluded effective treatment approaches,” the paper concludes.     

Kiat is excited by light therapy’s potential. “If we can create non-invasively a metabolically healthier microbiome through this extremely cheap and easy way, then inflammatory diseases and neurodegenerative diseases should be positively influenced,” he said.

Surfers Health Practice Principal Dr Mark Jeffery has been using lasers in his practice for more than four years and sees good results in his patients. He says the research supports the use of light therapy for a wide range of diseases including Parkinson’s, Alzheimer’s, depression and chronic pain.

“The reality is there are no real side effects from low level laser therapy and it’s one of the safest treatments you can ever do,” he says.  

Liebert says the promising results they have seen thus far will inform on a large, double-blinded randomised control trial planned for this year. “It has the potential to apply to huge fields of medicine,” she said.

Weldon’s neurologist, Chris Kneebone, is keeping an open mind on infrared light therapy’s potential. “We all just have to wait and see what the trial results tell us,” he said.

He has advice for people who wish to give it a try for their Parkinson’s. “If you want to give it a go, give it a go,” he said. “I’ve got no reason not to recommend it, but at this stage I’ve got no reason to think it is helpful either.”

As for Jarrett, she has no doubts that infrared light therapy has helped her. She is enjoying pottering around in her garden again and has more energy than she has had for a long time.

“I feel like I could take on the world again,” she said. “My garden has never looked better.”

Margaret Jarrett in the garden at her home in Adelaide (Morgan Sette/The Australian)

Suvi Mahonen is a Surfers Paradise-based journalist. Her work appears in The Australian, the Australian Quarterly, Mamamia and other health and lifestyle publications. Follow her on Facebook, YouTube and online art-selling platform Redbubble.

Feature photo credit: Morgan Sette for The Australian

21 Replies to “Parkinson’s disease: from the gut to the brain. Infrared light may improve the gut’s microbiome”

  1. Congratulations to all surfers health workers, you have been doing well to improve health facilities thank you for your good work.

  2. These Articles are fantastic and have so much information ,Suvi the research you put into your work is a credit to you.Well Done 😎

    1. Hi Lorraine 🙂
      Thank you for your question. Infrared light is delivered to your body through a device known as a laser. So the term ‘laser’ refers to a semiconductor device that emits these wavelengths of infrared light.

      1. Suvi, this is a great article on such an exciting topic!

        I’d just quibble a small bit about your last answer. Infrared light used in these therapies can be created using LEDs or using lasers, and the light created from these two sources are not exactly the same. Many of the articles online that explain the difference are too physics-y/jargon-y but I liked this article, posted by a company that sells equipment to acupuncturists.

        1. Thank you so much for pointing this out, David 🙂 I genuinely appreciate your help! And thank you for the article link. It’s very useful in explaining the difference! Thank you again for posting your comment, Suvi 🙂

        2. David, can we say that whether the light is cohoerent or not, that as long as the body absorbs the right quantity of photons of the right wavelength, that the difference in coherence doesn’t matter?

          1. Dear Caroline,

            Your point (or question) is excellent!

            Yes, our clinical trial data actually supports this. It’s exposure at the optimal wavelength that matters. However (and there’s always a however unfortunately), cold lasers have the ability to deliver light more quickly at higher intensity so treatment times are reduced. Also, I’ve seen much better research support for Laser over LED and therefore more data is available on the optimal dosage of laser light required for different indications). Practically speaking is Laser is coherent (ie, neatly organised and pointed) scientists are more easily able to measure the energy emitted per square cm of body tissue exposed per second and therefore translate this into a clinical trial and eventually therapeutic treatment protocols. LED produces scattered, uneven light, much of which bounces right back off the patient. Ones ability to measure exact dosage is therefore significantly compromised. While too much exposure is not a problem and doesn’t present a danger to the patient, it is unfortunately also typically not therapeutically beneficial.

            The SYMBYX Biome website FAQs sheet explains all of this well (I hope!?).

            Dr Wayne Markman
            SYMBYX Biome

    2. Dear Lorraine.

      Infrared essentially is simply one type of light wave which is largely determined by its wavelength (ie the distance between the beginning of the light wave and when it starts to repeat itself again). Red light has a different wavelength as does blue, green and violet.

      Laser is one example of the technology that emits a light wave (could be red, infrared, blue green etc). Laser light is different to LED for example.

      If you Google these terms you should find some interesting and useful information. If you are interested in the medical applications of laser light, (especially for Parkinson’s) please visit our website ( Take care!

      Dr Wayne Markman
      SYMBYX Biome

  3. My 75 year old father has parkinsons and is uncertain of this type of treatment therefore unwilling to spend the money.
    I told him I would purchase it if he would commit to 3 months of using it.
    He agreed but what I cannot confirm is should I purchase a red light laser or red light LED?
    Please help!

    1. Hi Steve 🙂

      Thank you so much for your enquiry.

      I’m not a doctor so I don’t know which one to recommend to you. But what I can do is recommend two companies which were involved in supplying infrared light therapy devices for the Australian Parkinson’s trials. These are Canadian company Vielight ( and Swedish company Irradia ( The cost for these devices ranges from $299 to $2,639. You can contact these companies directly about purchasing an appropriate device for your father’s condition.

      Another great option is the Dorset Men’s Shed in Australia. These guys have made over 650 red and infrared light therapy helmets for members of the public, and shipped their helmets all over the world. The feedback they get from people using these helmets has been extremely positive. Helmets cost $300 AUD (about $205 US and £157) plus postage. For enquiries and orders, contact Merv Chilcott at

      I hope this helps 🙂

    2. Steve I don’t think you can purchase laser for home use.

      Home devices are LED and these are proven to be effective in many things including brain changes.

      Best combination for brain repair published so far is 808 nm in the nose (I’m not kidding).

      Vielight sells this, it’s expensive, if you can find a high quality, sanitary 808 nm light substitute….

    3. Hello Steve. You should contact the team at SYMBYX Biome directly with all of your questions ( Dr Ann Liebert is our Chief Scientist.

      Dr Wayne Markman
      SYMBYX Biome

  4. Great article, I’ve been looking at red light therapy for over a year now. Here’s a blog from a guy who built his own red light helmet . I bought myself a laser device from Vityas last year for home use – has helped with general aches and pains and arthritic knees, works well on acu-points and trigger points. A few months ago I bought a red – IR LED unit from Redlightman for a nephew – he’s found it helped his diabetic neuropathy. Both units were under GBP100, so cost isn’t an issue, it’s a well researched field and lots of help available.

  5. As a skin cancer doctor I have an interest in the effects of the whole electromagnetic spectrum. It is well appreciated that UV has adverse effects with the ability to pull off elections and break bonds leading to mutation in DNA of skin cells. What is not so appreciated are the beneficial effects of sunlight, except Vit D production. Sun exposure and VIt D production relationship is variable seasonally and also by time of day.
    I feel there are beneficial effects from particularly infrared. If your shadow is longer than your body, early morning and late afternoon you are getting relatively more infrared than UV. Morning exposure conditions the skin and allows for better adaption to UV exposure in the middle of the day. This pattern of sun exposure entrains circadian rhythms that link to a range of beneficial effects including enhanced DNA repair mechanisms. People spend way too much time indoors under artificial light. Infrared and even visible light penetrate much deeper into the skin but are not as active. Obviously infrared can penetrate the skull. I look forward to further research and expansion of this Photobiomics science and application

    1. What an interesting and informative comment, David!
      Thank you so much for sharing your thoughts 🙂 I enjoyed reading what you had to say and it makes a lot of sense.
      Thank you again for sharing!

      1. Thank you all for the insightful comments. Are you aware if further developments of light therapy for Parkinson’s?

        If you or one of your loved ones stricken with this disease, which manufacturer’s product would you consider? Prices seem to be between 200 and 3000, which is a rather substantial spread.

        What wavelengths have shown promise? Is treatment directed to head and/or belly?

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