What Is Inflammation and How Food Affects It

Inflammation has become a popular wellness concept, often invoked to explain everything from fatigue to weight gain. The reality is more specific: chronic low-grade inflammation is a genuine physiological state with measurable causes and consequences, and diet is one of the most powerful modulators of it.

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Acute vs Chronic Inflammation: The Critical Distinction

Acute inflammation: The body's immediate response to injury or infection. Localised redness, swelling, heat, and pain. Necessary, protective, and self-resolving. This is beneficial inflammation.

Chronic low-grade inflammation: A persistent, systemic, low-level activation of immune pathways, without resolution. No localised symptoms (no visible redness or swelling) but measurable in blood via C-reactive protein (CRP), interleukin-6 (IL-6), TNF-alpha, and other cytokines.

Chronic inflammation is associated with virtually every major chronic disease: type 2 diabetes, cardiovascular disease, certain cancers, Alzheimer's disease, depression, and obesity.

How Diet Drives Inflammation

Pro-inflammatory dietary factors:

Trans fats (partially hydrogenated oils): Strongly pro-inflammatory, directly activate inflammatory signalling pathways. Now largely banned in EU but still present in some products.

Excess omega-6 fatty acids: Western diets have dramatically shifted toward omega-6 (from processed vegetable oils: soybean, sunflower, corn). High omega-6:omega-3 ratio (modern Western average: 15:1; optimal is 4:1 or lower) promotes production of pro-inflammatory eicosanoids.

Refined carbohydrates and added sugar: Rapid blood glucose spikes trigger inflammatory cytokine release. Advanced glycation end-products (AGEs) from high-temperature cooking of sugar and protein are directly pro-inflammatory.

Ultra-processed foods: Multiple ingredients in UPF (emulsifiers, preservatives, artificial colours) trigger low-grade immune activation and gut barrier disruption.

Excess alcohol: Disrupts intestinal barrier, allows bacterial endotoxins into circulation (endotoxaemia), a potent inflammatory trigger.

How Diet Reduces Inflammation

Omega-3 fatty acids (EPA and DHA): The most evidence-backed dietary anti-inflammatory intervention. EPA and DHA compete with arachidonic acid (the omega-6 precursor to pro-inflammatory eicosanoids) for the same enzymes, producing anti-inflammatory resolvins and protectins instead.

Food sources: Oily fish (salmon, mackerel, sardines, herring), 2-3 servings/week provides therapeutic levels.

Olive oil polyphenols (oleocanthal): Oleocanthal, the phenolic compound responsible for olive oil's throat sensation, inhibits COX-1 and COX-2 enzymes, the same pathway as ibuprofen. Extra virgin olive oil (EVOO), not refined olive oil, contains relevant oleocanthal levels. 4 tablespoons EVOO ≈ equivalent anti-inflammatory activity to a low-dose ibuprofen.

Dietary fibre: Fermentation of fibre produces butyrate, a short-chain fatty acid that directly reduces intestinal inflammation and strengthens the gut barrier, reducing endotoxin entry into circulation.

Polyphenols (berries, tea, dark chocolate, herbs): Multiple polyphenol classes reduce NF-κB signalling, the master inflammatory pathway. Berries, green tea, turmeric (curcumin), and resveratrol (red wine) all have evidence for reducing CRP and inflammatory markers in human studies.

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The Mediterranean Diet: The Most Evidence-Based Anti-Inflammatory Pattern

Rather than individual nutrients, the Mediterranean diet is the most thoroughly researched and effective anti-inflammatory dietary pattern, and the most practical to implement.

Core components:

• Extra virgin olive oil as primary fat (3-4 tbsp/day)
• Oily fish 2-3 times/week
• Legumes 4-5 times/week
• Vegetables and fruit abundantly (8-10 portions/day)
• Whole grains (not refined)
• Nuts and seeds daily (30g)
• Minimal red meat (1-2 times/week maximum)
• Minimal processed and ultra-processed food
• Herbs and spices liberally

Evidence: The PREDIMED trial (7,447 participants, 4.8 years) found Mediterranean diet adherence reduced cardiovascular events by 30% and measurably reduced inflammatory markers, compared to a low-fat control diet.

Inflammation Measurement

CRP (C-reactive protein) is the most clinically useful inflammatory marker available through standard blood tests. Normal range: under 1mg/L. Levels 1-3mg/L indicate low-grade chronic inflammation. Above 3mg/L indicates significant inflammation (though acute infection must be excluded).

If interested in your inflammatory status, a standard blood panel with high-sensitivity CRP (hsCRP) provides a useful baseline to work from.

The Bottom Line

Chronic low-grade inflammation is a real, measurable physiological state driven largely by diet quality, excess visceral fat, sleep disruption, and chronic stress. The most effective dietary anti-inflammatory interventions: omega-3 fatty acids from oily fish (2-3×/week), extra virgin olive oil as the primary fat, abundant colourful vegetables and fruit, legumes regularly, and minimising ultra-processed foods and refined carbohydrates.