Long-term effects of increasing omega-3, omega-6 and total polyunsaturated fats on inflammatory bowel disease and markers of inflammation: a systematic review and meta-analysis of randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 33084958 · doi:10.1007/s00394-020-02413-y
What was done
The authors systematically searched Medline, Embase, Cochrane CENTRAL, and trial registries for randomized controlled trials lasting at least 24 weeks in adults with or without inflammatory bowel disease (IBD). The review evaluated the long-term effects of higher versus lower intakes of long-chain omega-3 (LCn3), alpha-linolenic acid, omega-6, and total polyunsaturated fatty acids (PUFA) on IBD diagnosis, relapse, severity/worsening, pharmacotherapy, quality of life, and inflammatory biomarkers.
What was found
Across 83 included RCTs (41,751 total participants, 13 trials in IBD patients): - Increasing LCn3 yielded imprecise effects on IBD relapse (RR 0.85, 95% CI 0.72–1.01), IBD worsening (RR 0.85, 95% CI 0.71–1.03), and IBD diagnosis risk (RR 1.10, 95% CI 0.63–1.92). - LCn3 slightly reduced erythrocyte sedimentation rate (ESR: SMD -0.23, 95% CI -0.44 to -0.01), but faecal calprotectin estimates were imprecise and crossed null (MD 16.1 µg/g, 95% CI -37.6 to 69.8). - Outcomes for alpha-linolenic acid, omega-6, and total PUFA were sparse, showing little or no effect. All primary outcomes were classified as low-quality evidence.
Why it matters
This systematic review shows that long-term PUFA supplementation has little to no clinically meaningful benefit for preventing or managing inflammatory bowel disease.
Limits
All primary findings were graded as low-quality evidence due to imprecision and risk of bias. Only 13 of the 83 included trials directly enrolled patients with IBD, and data for alpha-linolenic acid, omega-6, and total PUFA were particularly sparse.
Cited by
- contradicts Omega-3 fish oils lower triglycerides, whereas omega-6 polyunsaturated fatty acids promote inflammation.