Short-Sightedness

A compound linked to how severe short-sightedness gets

Short-sightedness, or myopia, is projected to affect around half the world's population by 2050. Researchers comparing people with high myopia to people with normal vision found a specific gut bacteria byproduct, a compound called indole-3-acetic acid, at consistently lower levels in the blood of people with high myopia, and lower levels of this compound tracked with more severe disease. The bacteria that produce it were also reduced in the high myopia group.

Source: Gut microbiota-derived indole-3-acetic acid suppresses high myopia progression by promoting type I collagen synthesis

Confirmed with a direct experiment, not just observation

This wasn't left as a correlation. Researchers found that this gut bacteria compound directly promotes the production of type I collagen, a structural protein that helps keep the eye's shape stable, suggesting a genuine mechanism for how a gut bacteria shortfall could allow the eye to elongate too much, the physical change that drives worsening short-sightedness. A separate study went further, testing a specific bacterium, Bifidobacterium, using both genetic analysis in humans and a live experiment in guinea pigs with induced short-sightedness, and found the bacterium had a protective effect in both.

Source: Potential protective role of Bifidobacteria in myopia prevention: evidence from full-length 16S rRNA sequencing and bidirectional Mendelian randomization analysis

Antibiotics may play a role too

A mouse study found that disrupting gut bacteria with antibiotics changed how susceptible the mice were to developing short-sightedness when their eyes were exposed to lens-induced conditions that normally trigger it. This adds another angle to the emerging picture, suggesting the gut's bacterial state may influence not just how severe short-sightedness becomes, but how easily it develops in the first place.

What this means for you

Short-sightedness needs a proper eye exam and correction with glasses, contact lenses, or in some cases specific treatments to slow its progression in children, particularly since high myopia carries a higher lifetime risk of other eye conditions like retinal detachment and glaucoma. Time spent outdoors remains the best-evidenced way to reduce myopia risk in children. Given the genuine mechanistic and experimental evidence above, a varied, plant-rich, fibre-rich diet that supports gut bacteria capable of producing compounds like indole-3-acetic acid is a reasonable, evidence-aligned habit alongside standard eye care, though it isn't a substitute for proper myopia management. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.