The Surprising Connection Between Gut Health and Eye Health

Recent research has uncovered intriguing links between the gut microbiome and various eye diseases. The gut microbiome refers to the trillions of bacteria and other microorganisms that live in the gastrointestinal tract. This article explores how the gut microbiome may impact conditions like diabetic retinopathy, macular degeneration, dry eye, and more.

How is the Gut Connected to the Eyes?

Although the eyes may seem far removed from the gut, there are several ways the microbiome could influence ocular health:

Antigenic Mimicry

This is when gut bacteria produce substances similar to those found naturally in the eyes. The immune system may mistakenly identify these as foreign invaders and launch an attack, causing inflammation in the eyes.

Dysbiosis

An imbalance between healthy and unhealthy gut bacteria. Too many bad bacteria can erode the intestinal lining, allowing bacterial products to enter the bloodstream and circulate to the eyes.

Gut Mucosal Lymph Migration

Immune cells in the gut lining can travel via the lymphatic system to the eyes. If triggered by dysbiosis, they could drive inflammatory eye disease.

Leaky Gut

Excessive intestinal permeability allows bacteria, toxins, and undigested food particles to enter the bloodstream. This systemic inflammation may reach the eyes.

Gut Microbiome and Diabetic Retinopathy

High blood sugar in diabetes damages the tiny blood vessels supplying the retina, the light-sensitive tissue lining the back of the eye. This is called diabetic retinopathy and can cause vision loss. Research shows:

• Diabetic retinopathy patients have fewer anti-inflammatory gut bacteria and more pathogenic bacteria compared to healthy controls.
• They have decreased gut microbiome diversity overall.
• Dysbiosis promotes leaky gut and systemic inflammation, further damaging retinal blood vessels.
• Poor gut health may inhibit absorption of antioxidant nutrients needed to protect the retina.

Gut Microbiome and Macular Degeneration

Age-related macular degeneration (AMD) is deterioration of the macula, the central part of the retina responsible for sharp vision. Some theories on the gut-AMD link:

• Dysbiosis and leaky gut drive systemic inflammation that may hasten AMD progression.
• Certain gut microbes overactivate the complement system, exacerbating retinal inflammation in AMD.
• Poor nutrient absorption from gut dysbiosis may limit key antioxidants from reaching the macula.
• AMD patients have different gut microbiome profiles compared to healthy people. Mouse studies show high-fat diets and high sugar diets alter the microbiome in ways that promote AMD.

Gut Microbiome and Dry Eye

Dry eye disease is chronic dryness and irritation of the eye surface. Connections to the gut microbiome include:

• Sjögren’s syndrome patients, who have severe dry eye, have dysbiosis similar to lupus patients. Non-Sjögren’s dry eye patients also have imbalances but not as extreme.
• Dysbiosis and leaky gut promote inflammation, which can damage tear glands and goblet cells.
• Mouse studies show a high-fat diet increases dry eye disease by altering the gut microbiome.

How to Improve Your Gut Health for Better Eye Health

While more research is needed, there are steps you can take now to support a healthy gut microbiome:

• Eat more whole grains, fruits, vegetables, beans, nuts and seeds to increase short-chain fatty acids that reduce inflammation.
• Try probiotic foods like kimchi, tempeh, yogurt, kefir, sauerkraut, and kombucha, or consider a probiotic supplement.
• Load up on prebiotic foods like onions, garlic, asparagus, oats, and apples to feed beneficial gut bacteria.
• Limit processed foods, excess fat, sugar and alcohol, which can decrease microbial diversity.
• Discuss gut health with your doctor, including tests for food sensitivities or intestinal permeability.

The Bottom Line

An imbalanced gut microbiome may contribute to common eye conditions like diabetic retinopathy, macular degeneration and dry eye by increasing systemic and ocular inflammation. Research on how probiotics, prebiotics, diet and other interventions could support eye health through gut microbiome modulation is still emerging. But paying attention to your gut health is part of a holistic approach for protecting your eyes.