Chronic low-grade inflammation — the invisible root cause of modern disease

Unlike acute inflammation (the body's normal defence against trauma or infection), systemic chronic inflammation is a silent destroyer. It causes no direct pain, but constantly drains the immune system and damages healthy tissues at the cellular level.

Biochemical marker: hs-CRP and friends

Biochemically it is characterised by a persistent moderate rise in inflammatory cytokines (TNF-α, IL-6, IL-1β) and high-sensitivity C-reactive protein (hs-CRP) in the blood. Lifestyle medicine targets an hs-CRP below 1.0 mg/L. A result of 1.0–3.0 mg/L points to active lifestyle-driven inflammation.

The large review by Furman and colleagues (Nature Medicine 2019) maps how SCI is the shared soil for cardiovascular disease, type-2 diabetes, several cancers, neurodegeneration and depression. It is arguably the most important shared disease mechanism of the 21st century.

Inflammaging — the inflammatory component of ageing

Franceschi and Campisi (J Gerontol 2014) coined the term inflammaging — the chronic low-grade inflammation that accompanies ageing, partly driven by the SASP phenotype of senescent cells. These cells stop dividing but remain metabolically active and constantly release inflammatory signals.

Main triggers and how to dampen them

• Visceral fat — behaves as a standalone inflammatory organ
• Chronic psychological stress — cortisol resistance, sympathetic dominance
• Disrupted circadian rhythms and sleep debt (Irwin et al., Biol Psychiatry 2016 — one bad night raises IL-6 and TNF-α)
• Excess added sugar and refined carbs
• Fatty processed meats and trans fats
• Dysbiosis and a leaky gut barrier (LPS endotoxaemia)
• Periodontitis and gum inflammation (Tonetti et al., NEJM 2007)
• Chronic alcohol consumption

"Chronic inflammation does not have to be painful to be destructive."

Evidence-based suppression strategies

• Mediterranean pattern — PREDIMED (Estruch et al., NEJM 2018) showed a 30% reduction in cardiovascular events
• Omega-3 EPA/DHA 2 g+ daily (Calder, Adv Nutr 2017)
• Aerobic training 150 min/week + strength training 2× per week
• 7–9 h of sleep with a stable window
• Stress tools: slow breathing, yoga, meditation
• Vagal tone training (Bonaz et al., Front Neurosci 2018 — cholinergic anti-inflammatory reflex)
• Reducing visceral fat by ≥ 5% of body weight

Measure and track

To complete the inflammation picture also check IL-6, ferritin, fibrinogen, GGT, omega-3 index and waist-to-height ratio. Repeat measurement 12 weeks after a lifestyle intervention — biological inflammation responds slowly but surely.

Clinical note

Chronic low-grade inflammation is always a signal, not a diagnosis. Finding its source — diet, sleep, visceral fat, gut, teeth, chronic infection — is an individual clinical task. Interpreting a single hs-CRP without broader context is misleading.

The hidden role of oral health and periodontitis in systemic inflammation

Chronic gingivitis is one of the most underestimated sources of systemic inflammation. Gum-pocket bacteria (Porphyromonas gingivalis) regularly enter the bloodstream and raise hs-CRP. Tonetti et al. (NEJM 2007) showed that intensive periodontal treatment measurably improved endothelial function within 6 months. If hs-CRP stays high with no obvious cause, have a dentist assess your periodontal status.

Omega-3 index: a measurable brake on inflammation

The omega-3 index (EPA + DHA as % of red-cell membrane) is one of the few inflammation biomarkers you can shift ~2× in 3–4 months by lifestyle alone. Target for cardiovascular risk reduction is ≥ 8%; most Northern Europeans sit at 3–5%. Dose: 2 g EPA+DHA daily for 12 weeks, then re-measure. Calder (Advances in Nutrition 2017) shows this shifts eicosanoid synthesis toward the anti-inflammatory pathway.

• Fatty fish (salmon, mackerel, sardines) 3× per week
• Fish oil 1–2 g EPA+DHA per day if fish is not an option
• Vegan alternative: algae-based DHA oil 500–1000 mg
• Avoid excess omega-6 (sunflower, corn, soy oil) — they compete for the same enzymes

When to refer to rheumatology or internal medicine

If hs-CRP > 10 mg/L persists across two measurements without infection, plus morning joint stiffness > 30 min, unexplained weight loss or fever, a broader screen is warranted (ANA, RF, anti-CCP, ferritin, SPEP). Chronic inflammation can be the earliest signal of autoimmune disease.