What Inflammation Actually Does
February 5, 2026 · 5 min read
Inflammation has become a cultural shorthand for everything wrong with modern health. The biological reality is more precise — and more interesting. Inflammation is a defence system, not a disease.
Few words in contemporary health discourse are used as loosely as "inflammation." The biological reality is more precise — and more interesting — than the cultural shorthand suggests.
Acute Inflammation: The Design
Acute inflammation is the immune system's first-response mechanism. When tissue is damaged or a pathogen is detected, resident immune cells release chemical signals that increase blood flow to the affected area, recruit specialised immune cells, and raise local temperature to inhibit microbial growth.
The cardinal signs — redness, heat, swelling, pain — are not malfunctions. They are the mechanism working correctly.
The Resolution Phase
What is often overlooked is that inflammation has a resolution phase that is as active as the initiation phase. Specialised pro-resolving mediators (SPMs) — synthesised from omega-3 fatty acids — signal the immune system to stand down.
Failure of resolution — not just excessive initiation — is increasingly implicated in chronic inflammatory conditions.
Chronic Low-Grade Inflammation
Chronic, low-grade systemic inflammation is characterised by persistently elevated inflammatory markers (CRP, IL-6, TNF-α) without a specific acute trigger. The triggers are well-documented: excess adipose tissue, poor sleep, sedentary behaviour, chronic psychological stress, gut permeability, and certain dietary patterns.
Inflammation and the Brain
Inflammatory cytokines cross the blood-brain barrier and activate microglia — the brain's resident immune cells. Chronically activated microglia produce neurotoxic compounds and reduce BDNF expression.