Can infra-red light benefit the health of the gut microbiome?

There is evidence that both red and near infrared wavelengths can improve the quality of the bugs in the gut, and these in turn can change the way that the brain works. It seems weird that bugs in the belly can communicate with the brain, but it definitely is a thing, thanks to the Vagus nerve.

1. The Super-Highway: The Vagus Nerve

Think of the vagus nerve as a two-way super-highway connecting your gut and brain. Gut bacteria can send signals up this nerve that directly influence mood, anxiety levels, and even memory. If your gut is inflamed or imbalanced, those distress signals travel straight to your brain.

2. The Brain's Chemical Factory (Neurotransmitters)

Your gut microbes manufacture or regulate over 90% of your body's supply of key brain chemicals. They don't just stay in the gut; they influence the brain directly.

• Serotonin (The "Mood Stabilizer"): ~95% of your body's serotonin is produced in the gut. This regulates mood, sleep, appetite, and social behaviour. An unhealthy gut = low serotonin = increased risk of depression and anxiety.

• GABA (The "Calm-down" Chemical): Certain gut bacteria (like Lactobacillus and Bifidobacterium) produce GABA, which reduces fear, stress, and anxiety.

• Dopamine (The "Reward" & "Drive" Chemical): Gut microbes influence dopamine production, impacting motivation, focus, and pleasure.

3. The Immune System Gatekeeper (Inflammation Control)

Your gut houses ~70-80% of your immune cells. Gut bacteria train these cells to tell the difference between a real threat and a false alarm.

• The Problem: When the gut barrier becomes "leaky" (due to poor diet, stress, or antibiotics), bacteria and toxins can slip into the bloodstream. This triggers body-wide inflammation.

• The Brain Impact: The brain is exquisitely sensitive to inflammation. Chronic, low-grade inflammation from a leaky gut is now linked to depression, brain fog, Alzheimer's, Parkinson's, and even autism spectrum disorder symptoms. Inflamed body = inflamed, sluggish brain.

4. The Brain's Bouncer: The Blood-Brain Barrier (BBB)

Your BBB is a protective shield that keeps harmful substances out of your brain. A healthy gut microbiome produces short-chain fatty acids (SCFAs) (like butyrate) from digesting fibre. These SCFAs circulate in your blood and strengthen the BBB, making it "tight." A damaged microbiome leads to a "leaky" BBB, allowing toxins and inflammatory molecules to directly enter brain tissue.

5. Stress Response Regulator (The HPA Axis)

Your Hypothalamic-Pituitary-Adrenal (HPA) axis controls your cortisol ("stress hormone") release. Gut bacteria directly influence how this axis functions. A healthy microbiome helps you to bounce back from stress. An unhealthy one keeps your cortisol levels chronically high, which can literally shrink your hippocampus (the memory centre) and increase your risk for PTSD.

What Happens When It Goes Wrong (Real-World Examples)

Gut Problems with Brain Health Consequence.

• Low diversity of good bacteria.

• Higher rates of depression & anxiety.

• Overgrowth of bad bacteria (dysbiosis).

• Brain fog, poor concentration, fatigue.

• Low Lactobacillus & Bifidobacterium.

• Increased stress sensitivity, higher cortisol.

• Lack of SCFA-producing bacteria.

• Weakened blood-brain barrier, higher Alzheimer's risk.

• Chronic gut inflammation.

• Increased risk for Parkinson's disease (which often starts in the gut years before motor symptoms).

The Bottom Line for Brain Health

A healthy, diverse gut biome acts as a shield, chemical factory, and stress buffer for your brain. An unhealthy gut biome acts as a source of chronic inflammation, low mood, and cognitive decline.

This is why psychiatrists and neurologists are increasingly prescribing not just medication, but psychobiotics (probiotics for mental health) and dietary changes (like high-fibre, fermented foods, and avoiding ultra-processed foods) as a first-line treatment for mood and cognitive issues. To heal your brain, you often need to start with your gut.

The TheraPad is the best device to use, alternating between the red and near infrared settings. Drape it over the abdomen for twenty minutes once daily, and alternate the wavelengths on a daily basis. If you forget which one you used yesterday, it is no drama. The good bugs in the gut respond happily to both wavelengths.