The gut–eye axis is quickly becoming one of the most important emerging frontiers in glaucoma management. Recent evidence shows that gut microbiome dysbiosis may contribute to retinal ganglion cell degeneration through multiple converging pathways, including:

• systemic inflammation
• altered metabolite production (reduced glutathione, increased taurocholic acid)
• autoimmune mechanisms
• disruption of the blood–retinal barrier [1][2][3]

For those of us thinking beyond “IOP-only,” this is a compelling direction: gut optimization may offer neuroprotective leverage alongside conventional eye pressure management.

What the Evidence Suggests Is Happening (Mechanisms That Matter)

Glaucoma patients show characteristic gut microbiome shifts, most notably an increased Firmicutes/Bacteroidetes (F/B) ratio, which correlates negatively with retinal ganglion cell survival. [1][4]

Mendelian randomization data strengthens the case for causality and highlights taxa associated with increased POAG risk:

• Euryarchaeota
• Odoribacter
• Ruminoclostridium9
• Eubacterium rectale group …and taxa that appear protective:
• Lachnospiraceae
• Faecalibacterium
• Oscillospira
• Ruminococcaceae UCG011 [5]

These microbiome patterns appear relevant to glaucoma endophenotypes including intraocular pressure, vertical cup-to-disc ratio, and central corneal thickness. [5]

How dysbiosis may translate into glaucomatous neurodegeneration:

• antigenic mimicry + heat shock protein-specific T-cell infiltration in the retina
• LPS–TLR4 pathway activation
• altered metabolite production
• systemic inflammation
• gut barrier dysfunction enabling bacterial translocation and metabolites to reach ocular tissue [2][6][3]

One detail that stands out as especially actionable: Glutathione levels are decreased in glaucoma patients, and glutathione correlates negatively with harmful bacteria (including Bacteroides and elevated F/B ratio), while correlating positively with retinal ganglion cell survival. [4]

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Dietary Patterns With the Strongest Support

The clearest winners so far:

1) Mediterranean diet + dietary nitrates

Mediterranean diet (or MIND Diet) and increased dietary nitrate intake show the strongest evidence for glaucoma risk reduction. [7][8]

In particular, higher consumption of leafy green vegetables (nitrate-rich) is consistently associated with lower POAG risk—via nitric oxide-mediated endothelial support and stabilized ocular perfusion pressure. [7][8]

Level 1 evidence supports:

• adopting the Mediterranean diet pattern
• reducing ultra-processed foods to lower glaucoma risk. [7]

2) “Stacking” benefits appears stronger than isolated factors

Level 2 evidence suggests protective effects from dietary niacin, antioxidants, fruits, and vegetables. [7] And combining multiple beneficial dietary components may be more effective than single-factor approaches. [7][8]

3) Omega-3s deserve special attention

Glaucoma patients have lower blood levels of DHA and EPA. [10] Fish oil supplementation may support multiple glaucoma-relevant pathways including:

• lowering IOP
• regulating ocular blood supply
• alleviating inflammation
• diminishing oxidative stress [10]

4) Nitrates: especially strong mechanistic support

Dietary nitrates from dark green leafy vegetables appear particularly beneficial through nitric oxide pathways. [11]

5) A caution signal (limited evidence)

Selenium, calcium and iron intake may increase glaucoma risk, though the number of studies is limited. [11]

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Natural Compounds for the Gut–Eye Axis

This is where the gut–eye framing becomes practical. Several interventions map cleanly onto the mechanisms above:

Probiotics + Prebiotics

Direct clinical trials linking probiotics to glaucoma outcomes are lacking, but the rationale is compelling. [12][2][13] Multi-strain probiotics containing Lactobacillus and Bifidobacterium could theoretically support restoration of protective taxa (including Lachnospiraceae and Faecalibacterium) depleted in glaucoma. [5] Preliminary evidence suggests probiotic supplementation or fecal microbiota transplant can reduce ocular inflammation in related conditions. [13][14] Therapeutic modulation (probiotics, prebiotics, synbiotics, fecal microbiota transplantation) shows promise preclinically for ocular diseases including glaucoma. [12]

Resistant Starch

Resistant starch may help by increasing butyrate-producing bacteria and SCFA production—relevant to the metabolic dysregulation seen in glaucoma. [15][16] Mechanistic support is strengthened by the role of Faecalibacterium (protective in MR analyses). [5]

Berberine

Berberine aligns tightly with glaucoma-relevant biology: it may increase beneficial bacteria (Bacteroides, Bifidobacterium, Lactobacillus), reduce harmful species, and support anti-inflammatory and barrier-protective effects. [17][18] Its enhancement of glutathione pathways may be especially relevant given decreased glutathione in glaucoma patients. [4]

Butyrate Supplements

Butyrate supplementation may support colonocyte function, reduce endotoxemia, and strengthen gut barrier integrity, which are relevant to limiting bacterial/metabolite translocation to ocular tissues. [19][20]

Ginger Root

Ginger is supported by multiple relevant effects: increasing beneficial bacteria (Parabacteroides, Ruminococcaceae), improving tight junction proteins, and reducing inflammatory signaling (NF-κB, TNF-α, CRP). [21][22][23] Its antioxidant properties may also support glutathione pathways. [24]

Burdock Root + Sea Moss

These two ingredients, part of the Radiant MitoMAG formula, contain prebiotic fibers (inulin-type fructans and polysaccharides), with microbiome relevance. [25][19][26]

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Additional Nutrients Worth Noting

Among individual supplements, B vitamins currently have the strongest clinical evidence for potential neuroprotective effects in glaucoma. [9]

A range of compounds show antioxidative, neuroprotective, and vasoprotective properties in laboratory studies—flavonoids, carotenoids, curcumin, saffron, CoQ10, ginkgo biloba, and resveratrol / pterostilbene. [9]

Given the role of oxidative stress in glaucomatous neurodegeneration, antioxidant support is particularly relevant. [27][9] Nutrients that enhance glutathione production or provide direct antioxidant effects may help address the glutathione depletion observed in glaucoma. [4]

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Lifestyle Factors Still Matter

Beyond diet, the lifestyle signals that stand out:

• moderate aerobic exercise and high-quality sleep show protective effects potentially mediated through metabolic profiles and ocular perfusion improvements [8]
• smoking cessation remains critical, given its association with poorer diet quality and heightened oxidative stress [8][28]

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A Concrete Implementation Strategy

If your goal is gut-optimized glaucoma support, the evidence-supported approach described above organizes cleanly into four pillars:

1) Dietary foundation

Mediterranean diet pattern with:

• leafy greens (dietary nitrates)
• colorful fruits/vegetables (flavonoids, carotenoids)
• omega-3 rich fish
• minimized ultra-processed foods [7][8]

2) Targeted supplementation

Consider:

• multi-strain probiotics (Lactobacillus + Bifidobacterium)
• resistant starch (15–20 g daily)
• omega-3 fatty acids if dietary intake is insufficient
• B vitamins based on individual needs [9][10]

3) Natural compounds

• berberine (500–1000 mg twice daily)
• ginger (1–2 g daily)
• butyrate supplements (300–600 mg, 2–3 times daily) [17][21][23]

4) Lifestyle optimization

• regular moderate aerobic exercise
• adequate sleep
• smoking cessation
• stress management [8][28]

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Reality Check: Where the Field Still Has Limits

This is a high-potential area—but it’s still early. Key limitations include small sample sizes, short follow-ups, self-reported dietary data, and insufficient use of structural endpoints like retinal nerve fiber layer imaging. [8][13]

The next major step is clear: large-scale, multi-ethnic, genotype-stratified longitudinal studies and randomized controlled trials incorporating metagenomics, metabolomics, and structural ocular imaging. [8][2][14][29][30]

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What Are Your Thoughts?

If you’re already acting on this glaucoma-gut health connection, share what you’ve implemented and what you’ve noticed. This is exactly the kind of frontier where a knowledgeable community like ours can compare notes intelligently while the clinical trials catch up.

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References

1. The Role of Gut Microbiota in Glaucoma Progression and Other Retinal Diseases. Chen J, Chen DF, Cho KS. The American Journal of Pathology. 2023;193(11):1662-1668. doi:10.1016/j.ajpath.2023.06.015.
2. The Role of the Microbiota in Glaucoma. Huang L, Hong Y, Fu X, et al. Molecular Aspects of Medicine. 2023;94:101221. doi:10.1016/j.mam.2023.101221.
3. Microbiome Dysbiosis: A Pathological Mechanism at the Intersection of Obesity and Glaucoma. Pezzino S, Sofia M, Greco LP, et al. International Journal of Molecular Sciences. 2023;24(2):1166. doi:10.3390/ijms24021166.
4. Gut Microbiota and Derived Metabolomic Profiling in Glaucoma With Progressive Neurodegeneration. Zhang Y, Zhou X, Lu Y. Frontiers in Cellular and Infection Microbiology. 2022;12:968992. doi:10.3389/fcimb.2022.968992.
5. Causal Relationships Between Gut Microbiota and Primary Open-Angle Glaucoma: A Mendelian Randomization and Mediation Analysis of Glaucoma Endophenotypes. Zhou X, Xu J, Zhang X, Zhao Y, Duan X. Experimental Eye Research. 2024;240:109788. doi:10.1016/j.exer.2024.109788.
6. The Gut-Retina Axis: Uncovering the Role of Autoimmunity in Glaucoma Development. Yang Z, Tian D, Zhao X, Luo Y, Chen Y. Heliyon. 2024;10(15):e35516. doi:10.1016/j.heliyon.2024.e35516.
7. The Role of Diet and Nutrition in Glaucoma. Younis DA, Richter GM. Current Opinion in Ophthalmology. 2025;:00055735-990000000-00274. doi:10.1097/ICU.0000000000001193.
8. Diet, Exercise, and Lifestyle in Glaucoma: Current Evidence and Future Perspectives. Hanyuda A, Tsuda S, Himori N, et al. Nutrients. 2025;17(21):3369. doi:10.3390/nu17213369.
9. Nutritional Supplementation in the Prevention and Treatment of Glaucoma. Chaudhry S, Dunn H, Carnt N, White A. Survey of Ophthalmology. 2022 Jul-Aug;67(4):1081-1098. doi:10.1016/j.survophthal.2021.12.001.
10. Fish Oil in Glaucoma Treatment: From Biological Functions to Clinical Potential. Ye H, Liu Y, Xu Z, Wei X. Molecular Nutrition & Food Research. 2023;67(11):e2200727. doi:10.1002/mnfr.202200727.
11. The Relation Between Dietary Intake and Glaucoma: A Systematic Review. Ramdas WD. Acta Ophthalmologica. 2018;96(6):550-556. doi:10.1111/aos.13662.
12. From Gut to Eye: Exploring the Role of Microbiome Imbalance in Ocular Diseases. Tîrziu AT, Susan M, Susan R, et al. Journal of Clinical Medicine. 2024;13(18):5611. doi:10.3390/jcm13185611.
13. Clinical Trials Targeting the Gut-Microbiome to Effect Ocular Health: A Systematic Review. Russell MW, Muste JC, Kuo BL, Wu AK, Singh RP. Eye (London, England). 2023;37(14):2877-2885. doi:10.1038/s41433-023-02462-7.
14. The Link Between Gastrointestinal Microbiome and Ocular Disorders. Alfuzaie R. Clinical Ophthalmology (Auckland, N.Z.). 2023;17:2133-2140. doi:10.2147/OPTH.S415425.
15. Intermittent Fasting and Probiotics for Gut Microbiota Modulation in Type 2 Diabetes Mellitus: A Narrative Review. Zhang Z, Wang S, Sun G, Pan D. Nutrients. 2025;18(1):119. doi:10.3390/nu18010119.
16. Modulating the Gut Microbiome in Type 2 Diabetes: Nutritional and Therapeutic Strategies. Nikolaidis CG, Gyriki D, Stavropoulou E, et al. Nutrients. 2025;18(1):89. doi:10.3390/nu18010089.
17. Irritable Bowel Syndrome: Questions and Answers for Effective Care. Wilkinson JM, Gill MC. American Family Physician. 2021;103(12):727-736.
18. ACOG Practice Bulletin No. 210: Fecal Incontinence. Obstetrics and Gynecology. 2019;133(4):e260-e273. doi:10.1097/AOG.0000000000003187.
19. "Functional" GI Conditions in the Older Adult: DGBIs and Beyond. Wang XJ, Nguyen LAB. The American Journal of Gastroenterology. 2025;120(Suppl 10):S45-S55. doi:10.14309/ajg.0000000000003641.06.
20. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Fecal Incontinence. Bordeianou LG, Thorsen AJ, Keller DS, et al. Diseases of the Colon and Rectum. 2023;66(5):647-661. doi:10.1097/DCR.0000000000002776.
21. Targeting Gut Microbiota as a Therapeutic Target in T2DM: A Review of Multi-Target Interactions of Probiotics, Prebiotics, Postbiotics, and Synbiotics With the Intestinal Barrier. Chen K, Wang H, Yang X, et al. Pharmacological Research. 2024;210:107483. doi:10.1016/j.phrs.2024.107483.
22. An Update and Overview of the Various Health-Related Benefits of Probiotics: A Focus on Clinical Trials Demonstrating Efficacy, Tolerability and Use in Patients With Impaired Glucose Tolerance and Type 2 Diabetes. Toshimitsu T, Irie J. Diabetes, Obesity & Metabolism. 2025;27 Suppl 1:15-22. doi:10.1111/dom.16273.
23. Harnessing Prebiotics to Improve Type 2 Diabetes Outcomes. Iatcu OC, Hamamah S, Covasa M. Nutrients. 2024;16(20):3447. doi:10.3390/nu16203447.
24. Intestinal Barrier Impairment, Preservation, and Repair: An Update. Matar A, Damianos JA, Jencks KJ, Camilleri M. Nutrients. 2024;16(20):3494. doi:10.3390/nu16203494.
25. Natural Remedies for Irritable Bowel Syndrome: A Comprehensive Review of Herbal-Based Therapies. Abalo R, Gallego-Barceló P, Gabbia D. International Journal of Molecular Sciences. 2025;26(19):9345. doi:10.3390/ijms26199345.
26. Dietary Interventions and Irritable Bowel Syndrome - What Really Works?. Surdea-Blaga T, Cozma-Petrut A, Dumitraşcu DL. Current Opinion in Gastroenterology. 2021;37(2):152-157. doi:10.1097/MOG.0000000000000706.
27. Inflammation in Glaucoma: From the Back to the Front of the Eye, and Beyond. Baudouin C, Kolko M, Melik-Parsadaniantz S, Messmer EM. Progress in Retinal and Eye Research. 2021;83:100916. doi:10.1016/j.preteyeres.2020.100916.
28. Relationship of Lifestyle, Exercise, and Nutrition With Glaucoma. Perez CI, Singh K, Lin S. Current Opinion in Ophthalmology. 2019;30(2):82-88. doi:10.1097/ICU.0000000000000553.
29. Gut-Eye Axis in Ophthalmic Diseases: Focus on Ocular Neurodegeneration. Zhou L, Ma Y, Li X, Cao G. Biomedicine & Pharmacotherapy. 2025;193:118800. doi:10.1016/j.biopha.2025.118800.
30. The Gut-Eye Axis: The Retinal/Ocular Degenerative Diseases and the Emergent Therapeutic Strategies. Kammoun S, Rekik M, Dlensi A, et al. Frontiers in Cellular Neuroscience. 2024;18:1468187. doi:10.3389/fncel.2024.1468187.
31. Is Primary Open-Angle Glaucoma an Ocular Manifestation of Systemic Disease?. Wey S, Amanullah S, Spaeth GL, et al. Graefe's Archive for Clinical and Experimental Ophthalmology. 2019;257(4):665-673. doi:10.1007/s00417-019-04239-9.