How dietary patterns raise or lower chronic, low-grade inflammation.
What the evidence says
- Chronic low-grade inflammation ("metaflammation" / "inflammaging") is distinct from acute inflammation — modest but persistent elevations in circulating markers (CRP, IL-6, TNF-α) linked to obesity, metabolic syndrome, type 2 diabetes, NAFLD, and cardiovascular disease[1],[2]
- Pro-inflammatory dietary pattern: diets high in refined starches, sugar, and saturated and trans fats, and low in antioxidants, omega-3s, and fibre, activate the innate immune system — raising pro-inflammatory cytokines and lowering anti-inflammatory ones[3]
- Anti-inflammatory ("prudent" / Mediterranean) pattern: higher intake of fruits, vegetables, legumes, whole grains, nuts, and fish consistently lowers inflammatory markers in intervention trials[3],[2]
- Lower-glycaemic-index foods show protective effects against systemic inflammation markers; refined, high-glycaemic carbohydrates do the opposite[2],[3]
- *Saturated fat's pro-inflammatory route, in the paper's own words and at its own confidence: "recent advances in the field have uncovered *NLRP3 … inflammasome activation and IL-1β signalling as a key sensor of SFA-mediated metabolic stress in obesity and T2DM." The same review states the limit in the same breath — "There is some evidence, albeit not always consistent, for pro-inflammatory effects of dietary SFA. Much of this evidence comes from either in vitro or cross-sectional studies"[2]
- Long-chain omega-3 fatty acids (EPA and DHA) are substrates for specialised pro-resolving mediators (resolvins, protectins, maresins) that actively resolve inflammation, a step beyond merely suppressing it[2]
- *Flavonoids and anthocyanins move CRP and not the rest of the panel. The review's table reports "reduced plasma concentrations of CRP (*25–30%) in flavonoid consumers v. non-consumers" — an observational contrast, not an intervention effect — and the same row records **"no effects observed for plasma IL-6 or TNF-α concentrations."* Other studies in the same table are mixed, including rows reporting no effect on CRP* at all[2]
- Gut–inflammation axis: high-fat diets can increase intestinal permeability, letting bacterial lipopolysaccharide (LPS) enter circulation and trigger systemic inflammation ("metabolic endotoxaemia"); conversely, fermentable fibres yield short-chain fatty acids (especially butyrate) that support gut-barrier integrity[2]
- The evidence supports whole-diet-pattern approaches over single-nutrient interventions for lowering inflammation[3],[2]
- Inflammatory markers are also shaped by many non-dietary factors (age, body composition, physical activity, smoking, genetics), and there is no single agreed-upon best marker — so diet–inflammation effects are real but measured imprecisely[1]