When you think about protecting your eyesight, you may think about wearing sunglasses, having regular eye checks, managing your screen time and getting enough sleep.
But there is another fascinating area of research that you may not have considered: the relationship between your gut and your eyes.
Researchers are increasingly investigating what is known as the gut–eye axis — the idea that the gut microbiome and its metabolic and immune activity may influence processes occurring elsewhere in the body, including the eyes.
This doesn’t mean that having a “perfect” gut microbiome will prevent eye disease. The research is still developing, and much of the evidence is based on associations, laboratory studies and animal models rather than proof that changing the gut microbiome prevents or treats eye disease in humans.
Nevertheless, the connection is interesting and gives us another reason to focus on a varied, nutritious diet.
What Is the Gut–Eye Axis?
Your gut and your eyes may seem like completely separate parts of your body, but they are connected through several biological pathways.
The gut microbiome can interact with:
- The immune system
- Inflammatory pathways
- The nervous system
- Metabolic pathways
- Microbial metabolites such as short-chain fatty acids
These pathways can influence tissues throughout the body.
Research into the gut–eye axis has investigated possible relationships with conditions including:
- Age-related macular degeneration (AMD)
- Diabetic retinopathy
- Uveitis
- Glaucoma
- Dry eye disease
- Sjögren’s syndrome
Current evidence is particularly interesting in AMD and diabetic retinopathy, but the human evidence remains largely associative. A recent review concluded that the strongest signals appear to involve immune regulation, barrier function and microbial metabolites, rather than one specific “good” or “bad” bacterial species.
How Could the Gut Influence the Eyes?
Researchers are investigating several possible mechanisms.
One pathway involves systemic inflammation.
Changes in the gut microbiome may influence immune activity and the production of microbial metabolites. These signals can potentially affect tissues outside the digestive system, including the eye.
Another area of interest is the production of short-chain fatty acids (SCFAs).
Certain gut microorganisms ferment dietary carbohydrates and fibre to produce SCFAs such as butyrate. These compounds can influence immune regulation, inflammation and other biological processes.
The gut microbiome may also influence the metabolism of bile acids and tryptophan-derived compounds, both of which are being investigated in relation to eye health.
However, these mechanisms are still being worked out. We should therefore think of the gut microbiome as one potential contributor to eye health, rather than a single cause of eye disease.
Gut Health and Age-Related Macular Degeneration
Age-related macular degeneration is a major cause of vision loss, particularly as we get older.
Researchers have found differences in the gut microbiome of people with AMD compared with people without the condition, and experimental studies suggest that gut microorganisms may influence inflammation and other pathways involved in retinal health.
However, this does not mean that dysbiosis causes AMD.
A 2026 review of the gut–eye axis found that AMD has some of the stronger microbiome-related evidence among ocular diseases, but also emphasised that clinical translation remains limited and that more longitudinal and intervention studies are needed.
Importantly, we already have much stronger evidence for several established approaches to protecting eye health.
For example, eating a healthy diet rich in dark leafy greens and fish containing omega-3 fatty acids is recommended as part of healthy eye habits.
What About Diabetic Retinopathy?
Diabetic retinopathy is another condition being investigated through the gut–eye axis.
A 2026 systematic review and meta-analysis found that people with diabetic retinopathy showed differences in gut microbial composition and function compared with comparison groups. Some studies also found reductions in certain short-chain-fatty-acid-producing bacteria.
However, there was substantial variation between studies, and the researchers concluded that more work is needed before microbiome changes can be translated into specific clinical treatments.
This is an important distinction.
Gut health may be relevant to diabetic retinopathy, but managing blood glucose, blood pressure, cholesterol and diabetes remains central to reducing the risk of eye complications.
Nutrition can support these areas as part of an overall health-management plan.
What About Dry Eye?
Dry eye disease is another fascinating area of research.
Dry eye can occur for many reasons, including problems with tear production, tear evaporation, the eyelids and meibomian glands, environmental factors and inflammation.
Researchers have also found associations between gut microbiome changes and dry eye.
One small 2020 study compared people with Sjögren’s syndrome, people with environmental dry eye and healthy controls.
The researchers found differences in the gut microbiome between groups.
For example, the dry-eye group had higher levels of the genus Veillonella and lower levels of Subdoligranulum than the healthy control group. People with Sjögren’s syndrome also showed differences in several bacterial groups, including reduced Bifidobacterium compared with controls. Some microbiome characteristics were associated with measures of dry-eye severity.
However, this was a small study involving only 36 participants, so the results cannot be used to say that a particular bacterial imbalance causes dry eye.
More recent reviews continue to describe the relationship between gut microbiota and dry eye as promising but largely associative, with important differences between dry-eye subtypes.
Can Probiotics and Prebiotics Help Your Eyes?
This is another area receiving attention.
A probiotic is a live microorganism that, when administered in an adequate amount, provides a health benefit.
A prebiotic is a substrate that is selectively utilised by microorganisms and provides a health benefit.
Some clinical studies have investigated whether combining probiotics and prebiotics can improve dry-eye symptoms.
One small double-masked randomised trial involving 41 people with dry eye found that four months of probiotic and prebiotic supplementation improved a measure of dry-eye symptoms compared with placebo. However, the researchers found no significant improvement in the inflammatory biomarkers they measured.
This is encouraging, but it is still preliminary evidence.
There isn’t currently enough evidence to recommend probiotics or prebiotics as a standard treatment for eye disease.
And remember: fermented foods are not automatically probiotic foods.
Foods such as kimchi, sauerkraut and miso may contain live microorganisms, but whether a particular food meets the scientific definition of a probiotic depends on the microorganisms present and the evidence for a health benefit.
How Can You Support Your Gut?
You don’t need to buy a collection of gut-health supplements.
One of the most practical approaches is to eat a varied, fibre-rich diet.
Include a mixture of:
Wholegrains
- Oats
- Wholegrain bread
- Brown rice
- Quinoa
- Wholegrain pasta
Vegetables
Aim for a variety of colours and types.
Fruit
Different fruits provide different fibres and plant compounds.
Legumes
- Lentils
- Chickpeas
- Beans
- Peas
Nuts and Seeds
- Almonds
- Walnuts
- Chia seeds
- Pumpkin seeds
- Flaxseeds
These foods provide fibre and a wide range of plant compounds, including polyphenols.
What Are Polyphenols?
Polyphenols are naturally occurring plant compounds found in many foods.
Sources include:
- Fruit
- Vegetables
- Wholegrains
- Herbs
- Spices
- Tea
- Cocoa
- Nuts
- Extra virgin olive oil
Polyphenols can interact with the gut microbiome and many biological pathways involved in health.
Rather than focusing on one particular polyphenol, a practical approach is simply to increase the variety of plant foods in your diet.
And Don’t Forget the Nutrients We Know Matter for Eye Health
While the gut–eye axis is fascinating, we shouldn’t overlook the nutrition factors with a much stronger evidence base.
Leafy Green Vegetables
Spinach, kale and other dark leafy greens provide lutein and zeaxanthin, carotenoids that accumulate in the retina.
Research has found that people with diets rich in leafy green vegetables may have a lower risk of AMD.
Fish
Salmon, sardines, tuna and other fish provide omega-3 fatty acids and can be part of a healthy dietary pattern.
Fruit and Vegetables
A varied intake provides vitamin C, carotenoids, polyphenols and many other nutrients and plant compounds.
Eggs
Eggs provide nutrients including lutein and zeaxanthin, along with protein and other vitamins and minerals.
Nuts and Seeds
These provide healthy unsaturated fats, vitamin E and other nutrients.
A varied diet is much more important than focusing on a single “eye superfood”.
What About Eye Supplements?
You may have heard of the AREDS2 supplement formula for age-related macular degeneration.
This is a very different situation from taking a general “eye health” supplement.
The AREDS and AREDS2 clinical trials found that specific high-dose nutrient combinations can slow progression from intermediate to advanced AMD in people with the relevant stage of disease.
They do not prevent AMD from developing in people who don’t have it, and they are not recommended for everyone.
Anyone considering an AREDS2 formulation should discuss it with their ophthalmologist or other eye-care professional.
Food remains an important part of overall eye health, even when a specific supplement is medically indicated.
So, Should You Eat Two Probiotic Foods Every Day?
Rather than setting a strict target of two probiotic foods every day, I would focus on variety.
Include fermented foods that you enjoy, particularly products that specify they contain live cultures.
For example:
- Yoghurt containing live cultures
- Kefir
- Some fermented vegetables
- Tempeh
- Natto
At the same time, eat plenty of fibre-rich plant foods to support your gut microbiome.
If you have high blood pressure or another condition where sodium intake matters, remember that some fermented foods can be quite salty.
You Don’t Need a Perfect Microbiome
One of the biggest problems with online gut-health advice is the idea that everyone needs exactly the same collection of “good bacteria”.
Your microbiome is unique and dynamic.
There is no single bacterial profile that has been established as the perfect microbiome for every person.
The current research suggests that microbial function may be more important than simply counting particular bacteria.
And even when a microbiome difference is found in people with an eye disease, we can’t automatically assume that changing that bacterial pattern will prevent or treat the condition.
Take Home Message
The relationship between your gut and your eyes is an exciting area of nutrition and medical research.
There is increasing evidence that the gut microbiome may influence immune regulation, inflammation and metabolic signalling that could affect eye health. However, much of the human evidence is still associative, and we are not yet at the stage where improving your gut microbiome can be considered a proven way to prevent or treat eye disease.
So don’t feel that you need a special “eye probiotic” or expensive gut-health supplement.
Instead, focus on what we already know supports your overall health:
Eat a varied diet rich in fruit, vegetables, wholegrains, legumes, nuts and seeds. Include fish and other nutritious protein foods. Enjoy fermented foods that you like. Stay physically active. Don’t smoke. Manage conditions such as diabetes and high blood pressure. And have regular eye examinations.
Supporting your gut may be one piece of the puzzle — but looking after your whole body is what matters most.
How Feed Your Future Dietetics Can Help
Nutrition advice can become confusing when social media turns every new research finding into a “miracle food”.
At Feed Your Future Dietetics, I help you separate emerging research from established nutrition advice and translate the evidence into practical strategies you can actually use.
Whether you’re looking to improve your overall diet, support gut health, manage a health condition or simply build a more balanced way of eating, nutrition can be personalised around your individual needs and preferences.
With over 10 years of experience supporting Australians with their nutrition and health goals, Feed Your Future Dietetics provides individualised dietetic support Australia-wide via Telehealth using Zoom or Microsoft Teams.
To learn more or book an appointment:
ashleigh@feedyourfuturedietetics.com
References
- Floyd JL, Grant MB. The Gut-Eye Axis: Lessons Learned from Murine Models. Ophthalmology and Therapy. 2020;9(3):499–513.
- Moon J, Yoon CH, Choi SH, Kim MK. Can Gut Microbiota Affect Dry Eye Syndrome? International Journal of Molecular Sciences. 2020;21(22):8443.
- The Gut-Eye Axis and Microbiome in Ophthalmic Diseases: A Narrative Review. 2026. This review synthesises evidence across AMD, diabetic retinopathy, glaucoma, uveitis, dry eye and Sjögren’s syndrome and highlights the predominantly associative nature of current human evidence.
- Sadeghi R, Abdol Homayuni MR, Fateh A, et al. The gut-eye axis: microbiota and their role in diabetic retinopathy: a systematic review and meta-analysis. BMC Ophthalmology. 2026;26:7.
- Wang C, et al. The gut-eye axis in blinding eye diseases: microbiota-driven immune dysregulation and immunomodulatory therapies. International Ophthalmology. 2025.
- Gut-ocular surface axis in dry eye disease: phenotype-specific mechanisms, evidence, and microbiome-targeted interventions. 2026.
- Tavakoli A, Markoulli M, Papas E, Flanagan J. The Impact of Probiotics and Prebiotics on Dry Eye Disease Signs and Symptoms. Journal of Clinical Medicine. 2022;11(16):4889.
- The Impact of Probiotics and Prebiotics on Ocular and Systemic Inflammation in Dry Eye Disease: a double-masked, randomised controlled trial. 2025.
- Hill C, Guarner F, Reid G, et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology. 2014;11:506–514.
- Gibson GR, Hutkins R, Sanders ME, et al. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics consensus statement on the definition and scope of prebiotics. Nature Reviews Gastroenterology & Hepatology. 2017;14:491–502.
- National Eye Institute. Keep Your Eyes Healthy. Updated 2024.
- National Eye Institute. AREDS/AREDS2 Clinical Trials. Updated March 2026.
- National Eye Institute. AREDS/AREDS2 Frequently Asked Questions.
