Treating the gut-brain axis with laser therapy

Research indicates the benefits of photobiomodulation (PBM) including enhancing mitochondrial function, modulating the neuroimmune and microbiome-gut-brain axis and increasing beneficial bacteria in the microbiome.

Treating the gut-brain axis with PBM can enhance neurogenesis, reduce inflammation and positively affect depression, sleep and cognition.

Photobiomodulation

Photobiomodulation (PBM), the therapeutic process of modulating biological tissues using photonic energy, is gaining traction for its health benefits. PBM involves the use of light within specific wavelengths that can penetrate tissues and interact with cellular components to stimulate cellular function, promote healing and reduce inflammation. A growing area of interest is the role of PBM in enhancing gut-brain communication, a critical aspect of overall health. This article explores how PBM can positively influence this vital interaction, potentially offering new avenues for treating various health conditions.

The gut-brain axis

The gut-brain axis (GBA) is a complex, bidirectional communication network linking the central nervous system (CNS) and the enteric nervous system (ENS). It involves neural, hormonal and immunological signaling pathways. Beyond digestive function and satiety, its roles in other physiological aspects have been gaining attention. The GBA plays a crucial role in maintaining homeostasis, influencing mood, cognition and gastrointestinal function. Research has shown that alterations in gut-brain axis interactions are linked to gut inflammation, chronic pain, eating disorders and stress response, being related to conditions such as irritable bowel syndrome (IBS), depression and anxiety.^1,2

Benefits of PBM for gut and brain health

Emerging research suggests PBM can positively impact gut health.  A case study conducted in a patient undergoing cancer treatment showed significant changes in microbiome diversity after PBM treatment: an increased number of beneficial bacteria and decreased number of potentially pathogenic ones.³ Positive changes in gut microbiome were also observed in another study in rats with type 2 diabetes which received duodenal lumen irradiation with PBM.⁴

The primary target of PBM is cytochrome c oxidase, a component of the mitochondrial respiratory chain in the cell. This interaction enhances cellular respiration, leading to increased adenosine triphosphate (ATP) production, reduced oxidative stress and modulation of inflammation.^5,6 Additionally, PBM’s neuroprotective and neuroregenerative effects have been well-documented. PBM can reduce neuroinflammation, promote neurogenesis and enhance synaptic plasticity. These effects contribute to improved cognitive function and mood. Clinical studies have shown PBM can alleviate symptoms of depression, anxiety and cognitive decline.^7,8

A case study was conducted to determine the effect of PBM on the microbiome. The treatment consisted of infrared laser treatment (904 nm; 700 Herz pulse frequency; 861.3 total joules) three times a week for 11 weeks. The result was an increase in the number of known beneficial bacteria (Akkermansia, Faecalibacterium and Roseburia) and a decrease in potentially pathogenic bacteria. Treatment of 861.3 joules at 1400 mW takes 10 minutes.⁹

A randomized controlled study conducted with mild-to-moderate Alzheimer’s disease patients showed that PBM applied through a helmet and belt device was able to improve scores in different tests suggesting improved cognition.¹⁰ Also, a study in mice model of Alzheimer’s disease showed animals treated with PBM on the abdomen presented improved learning retention, reduced amyloidosis and tau phosphorylation in the hippocampus, and significantly altered the expression levels of 509 proteins involved in hormone synthesis, phagocytosis and metabolism as well as significantly altered the diversity and abundance of the microbiome.¹¹

The mechanism behind the observed effects of PBM on gut-brain axis are not fully elucidated; however, one possible mechanism is through the vagus nerve stimulation (cranial nerve X). The vagus nerve is the major nerve of the parasympathetic system and acts as a primary conduit of communication between the gut-brain axis due to its efferent and afferent roles, regulating several organ functions, including gut motility. It has been suggested that many of the effects of the gut microbiota or potential probiotics on brain function are dependent on vagal activation.¹ It has been shown that laser irradiation can provide laser stimulation of the vagus nerve bundle in an in-vivo rat model.¹²

Final thoughts

PBM devices, ranging from handheld lasers to full-body light beds, are becoming more accessible for clinical and home use. These devices can be integrated into wellness routines to enhance gut-brain axis communication. Future research should focus on optimizing PBM protocols for individual needs and further elucidating the mechanisms underlying its benefits. As the evidence base grows, PBM (within the red and near-infrared wavelengths) has the potential to be a mainstream therapeutic modality for enhancing gut-brain health.¹³ Specifically considering that it is a noninvasive therapy, with few reported adverse effects, well tolerability and positive effects on gut microbiota. However, further research is needed to evaluate its effects on other gut microbiome-related disorders and determine the most effective doses and durations.² Photobiomodulation offers a promising approach to enhancing gut-brain axis communication. By modulating cellular function and reducing inflammation, PBM can support both gut-brain axis health. As research continues to unfold, PBM may emerge as a valuable tool in the integrative health toolbox, promoting holistic well-being through the optimization of the gut-brain axis.

FRANCISCO CIDRAL, ND, MSC, PHD, POSTDOC, is the founder and CEO of Scientifica Consulting. He holds a master’s degree and PhD in neurosciences and a postdoctorate in health sciences. Cidral is a professor of integrative medicine and neurophysiology, with a specialization in laser acupuncture and photobiomodulation. He has authored more than 35 scientific publications and books. Cidral is a board member of various scientific journals and international research groups. He can be contacted at cidral@scientificaconsulting.com.

References

1. Cryan JF, Dinan TG. Mind-altering microorganisms: The impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci. 2012;13(10):701-712. PubMed. https://pubmed.ncbi.nlm.nih.gov/22968153/. Accessed July 9, 2024.
2. Jahani-Sherafat S, et al. The effectiveness of photobiomodulation therapy in modulation the gut microbiome dysbiosis related diseases. Gastroenterol Hepatol Bed Bench. 2023;16(4):386-393. PubMed. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10835098/. Accessed July 9, 2024.
3. Bicknell B, et al. Modifying the microbiome as a potential mechanism of photobiomodulation: A case report. Photobiomodulation, photomedicine and laser surgery. 2022;40(2):88–97. https://www.liebertpub.com/doi/10.1089/photob.2021.0057. Accessed July 11, 2024.
4. Min SH, et al. Duodenal dual-wavelength photobiomodulation improves hyperglycemia and hepatic parameters with alteration of gut microbiome in type 2 diabetes animal model. Cells. 2022;11(21):3490. PubMed. https://pubmed.ncbi.nlm.nih.gov/36359885/. Accessed July 9, 2024.
5. Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophys. 2017;4(3):337-361. PubMed. https://pubmed.ncbi.nlm.nih.gov/28748217/. Accessed July 9, 2024.
6. Chung H, et al. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng. 2012;40(2):516-533. PubMed. https://pubmed.ncbi.nlm.nih.gov/22045511/. Accessed July 9, 2024.