Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials
PubMed 22889633 · doi:10.1016/j.jand.2012.03.029
What was done
Authors systematically reviewed randomized controlled trials searching MEDLINE, the Cochrane Controlled Trials Register, and EMBASE without language restrictions to evaluate the effect of dietary linoleic acid on biologic markers of chronic inflammation in healthy noninfant populations. Fifteen trials met inclusion criteria (eight parallel and seven crossover design).
What was found
None of the 15 included studies found statistically significant increases in major inflammatory markers, including C-reactive protein, fibrinogen, plasminogen activator inhibitor type 1, cytokines, soluble vascular adhesion molecules, or tumor necrosis factor-alpha. The only significant findings were altered metabolite excretion in two studies (one reporting higher prostaglandin E2 and lower 2,3-dinor-thromboxane B2; another reporting higher tetranorprostanedioic acid excretion), neither interpreted as indicating increased inflammation. The abstract provides no pooled quantitative effect estimates.
Why it matters
The findings challenge the theoretical concern that dietary omega-6 polyunsaturated fatty acids promote systemic chronic inflammation in healthy humans.
Limits
The abstract does not report total participant count, intervention duration, linoleic acid dosages, or quantitative pooled effect sizes. Findings are limited to healthy populations and cannot be generalized to clinical populations with active inflammatory diseases.
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- contradicts Omega-3 polyunsaturated fatty acids from fish oils lower triglycerides, whereas omega-6 polyunsaturated fatty acids are pro-inflammatory.