How to Lower My Dementia Risk: The Gut–Brain Insight Most People Miss

If you’ve ever asked, “how can I lower my dementia risk?” you’re not alone.

Most people assume the answer lies in brain training apps, supplements, or waiting for early symptoms before taking action. But emerging research suggests something more fundamental:

The trajectory of your cognitive health may be shaped years earlier—by systems outside the brain.

One of the most compelling examples of this comes from a little-known molecule called 5-HIAA.

What is 5-HIAA—and why does it matter?

5-HIAA (5-hydroxyindoleacetic acid) is a breakdown product of serotonin, the neurotransmitter most commonly linked to anxiety and depression.

At first glance, that might not sound particularly relevant. But here’s the critical point:

• Around 90% of serotonin is produced in the gut, not the brain

• The gut microbiome plays a key role in regulating this process

• 5-HIAA reflects how your body is processing this system overall

In other words:

5-HIAA is not just a “waste product”- it’s a reflection of your gut–brain axis in action

The research: a link to dementia risk

A recent longitudinal study examined older adults over time, measuring a range of gut-derived metabolites and tracking who went on to develop dementia.

One finding stood out:

• Individuals with higher levels of 5-HIAA had around a 40% lower risk of developing dementia

This wasn’t just a weak association:

• It remained significant after adjusting for multiple variables

• It predicted time to dementia onset

• It outperformed several traditional inflammatory markers

This suggests that:

The way your body processes serotonin - driven largely by your gut - may be linked to long-term brain health.

Why this matters if you want to lower your dementia risk

If your goal is to lower your dementia risk, this changes the conversation.

Instead of focusing only on the brain, you need to consider:

1. The gut microbiome

Your microbiome influences:

• System inflammation

• Serotonin production

• Downstream metabolites like 5-HIAA

Disruption here can shift the entire gut–brain signalling system.

2. Systemic physiology (not isolated biomarkers)

5-HIAA is not acting alone. It is part of a broader network involving:

• Inflammation

• Metabolic health

• Sleep and circadian rhythm

• Stress physiology

This aligns with a key principle in longevity medicine:

Cognitive decline is rarely caused by a single factor - it emerges from interacting systems over time

3. Early intervention - not late reaction

Most people only think about dementia when symptoms appear.

But by then:

• Neurodegenerative processes are often already established

• The opportunity for prevention is reduced

The real opportunity lies years earlier, when these systems are still modifiable.

Can you test 5-HIAA?

Yes—but this is where clinical nuance matters.

5-HIAA can be measured:

• In urine (commonly)

• In blood (less routinely)

However:

• It is not currently a validated clinical tool to assess dementia risk

• It does not tell you exactly what to change in isolation

Think of it as:

A research-level signal that highlights the importance of the gut–brain axis, rather than a standalone diagnostic test

So how do you actually lower your dementia risk?

If you’re serious about reducing risk, the focus should shift from single markers to system-level optimisation.

At Everhealth, this means targeting the primary constraints that shape long-term brain health:

Metabolic health & fuel utilisation

• Insulin resistance is one of the strongest drivers of cognitive decline

• Stable energy metabolism supports neuronal function

Cardiovascular health

• What’s good for your heart is good for your brain

• Blood flow and vascular integrity are critical

Sleep & circadian alignment

• Deep sleep supports waste clearance from the brain

Physiological stress & recovery

• Chronic stress alters both gut function and brain signalling

Gut function & microbiome health

• Diversity and stability influence the gut–brain axis directly

The key takeaway

If you’re asking “how can I lower my dementia risk?”, the answer is not:

• One supplement

• One test

• One quick fix

It’s this:

You need to understand - and actively manage - the different biological systems that shape how your brain ages.

Start with clarity

If you want to understand your personal risk and what to do about it, the first step is not guessing.

At Everhealth, the Clarity Assessment is designed to:

• Identify the systems driving your long-term health trajectory

• Highlight early risks before they become problems

• Give you a structured, medically grounded plan

👉 Start with the Everhealth Longevity Quiz or book your Clarity Assessment today