By Craig Weatherby
People sometimes take fish oil hoping that it will help alleviate inflammation-related conditions such as arthritis or allergies.
A new epidemiological study supports this long-presumed benefit of seafood-source omega-3s ... whose credibility is bolstered by their proven biological effects.
We should note that, with regard to specific conditions, the precise inflammation-related powers of fish oil remain to be proven by high-quality clinical trials.
The encouraging findings also applied to glucosamine and chondroitin … two supplements used by people with osteoarthritis.
Before examining the new findings, we'll quickly review what's known about seafood-source omega-3s and inflammation.
Omega-3s and inflammation
Omega-3s (DHA and EPA) are the essential precursors to the inflammation-damping members of a family of key inflammation-regulating compounds called prostaglandins.
It's wise to ensure ample intake of both omega-3s, by eating seafood frequently and/or taking fish, krill, or other marine-life oils.
Excess intake of omega-6 fats from the cheapest vegetable oils – which is typical of the American diet – promotes excessive production of pro-inflammatory prostaglandins, and a lack of inflammation moderating influence from omega-3s.
This “omega imbalance” is strongly associated with artery disease, cancer, depression, diabetes, and other major conditions.
And it was recently discovered that when we consume these omega-3s from fish they metabolize into compounds (resolvins and protectins) that end inappropriate, damaging inflammation.
As the authors of a recent evidence review wrote, “Dietary omega-3 fatty acids are associated with … lower levels of inflammation … in cardiovascular disease and other chronic and acute diseases.” (Rangel-Huerta OD et al. 2012).
For an overview of the inflammation-related effects of EPA and DHA see the “Long-chain omega-3s: Truly essential to life and health” section of our Omega-3 Facts & Sources page.
Now, an analysis of data from America's large, ongoing diet-health survey lends more weight to the idea that omega-3s from fish help keep inflammation under control.
This matters because most major health conditions – cancer, cardiovascular disease, Alzheimer's, diabetes, arthritis, and more – are either promoted or exacerbated by chronic inflammation.
Analysis links fish oil to anti-inflammatory effect
The new epidemiological study was performed by researchers from the Fred Hutchinson Cancer Research Center and the University of Washington in Seattle (Kantor ED et al. 2012).
A team led by Elizabeth Kantor of the Hutchinson Center analyzed data from a nationally representative sample of 9,947 adults participating in the National Health and Nutrition Examination Survey (NHANES).
The people who reported regular use of fish oil supplements had 16 percent lower levels of a key inflammation marker called CRP (C-reactive protein).
In addition, those who reported regular use of glucosamine or chondroitin supplements had 17 percent and 22 percent lower levels of CRP, respectively.
As they wrote, “[Other] studies, plus our current study in a representative U.S. population, provide evidence for the anti-inflammatory effects of long-chain omega-3 PUFAs in humans …” (Kantor ED et al. 2012)
They followed that comment with key points about the practical meaning of their study's findings (Kantor ED et al. 2012):
  • “… and they support one of several mechanisms by which long-chain omega-3 PUFA intake may reduce the risk of cardiovascular disease, some cancers, and total mortality.”
  • This study adds biologic plausibility to previous studies, which have shown beneficial effects of these supplements on chronic diseases.”
  • “Given the number of diseases with which inflammation is associated, such as cancer and cardiovascular disease, there is a need to find safe and effective ways to reduce inflammation.”
  • “Research suggests that these 3 supplements have excellent safety profiles, supporting their potential role in disease prevention. It is therefore important that the potential anti-inflammatory role of these supplements be further investigated.”
Interestingly, the Seattle team noted that the relatively low CRP levels seen in those who reported using fish oil, glucosamine, or chondroitin supplements matches the range of reductions seen with prescription statin drugs such as Lipitor and Crestor … and their antiinflammatory effects are believed to account for much of their cardiovascular health benefit.
Other supplements showed no effect
The Seattle-based scientists saw no impact on CRP levels among people who reported taking any of a range of other supplements, including MSM (methylsulfonylmethane), pycnogenol/POC, garlic, ginkgo, or saw palmetto.
 These five were the only other supplements whose use was compared with inflammation levels. However, CRP is not the only marker for inflammation.
And as the Seattle group noted: “it is … possible that these supplements may affect inflammation downstream of CRP or that these supplements may not be associated with inflammation in humans.” (Kantor ED et al. 2012)
Unfortunately, they did not look for connections between consumption of supplemental curcumin – one of the most promising candidates for natural inflammation control – and CRP levels.
But that omission is understandable, given the relative novelty and rarity of curcumin supplements in drug and health retail chains in the U.S.
  • Alcock J, Franklin ML, Kuzawa CW. Nutrient signaling: evolutionary origins of the immune-modulating effects of dietary fat. Q Rev Biol. 2012 Sep;87(3):187-223. Review.
  • Calder PC. The role of marine omega-3 (n-3) fatty acids in inflammatory processes, atherosclerosis and plaque stability. Mol Nutr Food Res. 2012 Jul;56(7):1073-80. doi: 10.1002/mnfr.201100710. Review.
  • Cavicchia PP, Steck SE, Hurley TG, Hussey JR, Ma Y, Ockene IS, Hébert JR. A new dietary inflammatory index predicts interval changes in serum high-sensitivity C-reactive protein. J Nutr. 2009 Dec;139(12):2365-72. doi: 10.3945/jn.109.114025. Epub 2009 Oct 28.
  • Chen Y, Wang J, Nie R, Zhou S. Endogenous pro-resolving and anti-inflammatory lipid mediators: The new hope of atherosclerotic diseases. Med Hypotheses. 2008 Apr 28. [Epub ahead of print]
  • Clària J, Dalli J, Yacoubian S, Gao F, Serhan CN. Resolvin D1 and resolvin D2 govern local inflammatory tone in obese fat. J Immunol. 2012 Sep 1;189(5):2597-605. doi: 10.4049/jimmunol.1201272. Epub 2012 Jul 27.
  • Floegel A, Chung SJ, von Ruesten A, Yang M, Chung CE, Song WO, Koo SI, Pischon T, Chun OK. Antioxidant intake from diet and supplements and elevated serum C-reactive protein and plasma homocysteine concentrations in US adults: a cross-sectional study. Public Health Nutr. 2011 Nov;14(11):2055-64. doi: 10.1017/S1368980011000395. Epub 2011 Mar 18.
  • Gao L, Faibish D, Fredman G, Herrera BS, Chiang N, Serhan CN, Van Dyke TE, Gyurko R. Resolvin E1 and Chemokine-like Receptor 1 Mediate Bone Preservation. J Immunol. 2012 Dec 14. [Epub ahead of print]
  • Ji RR, Xu ZZ, Strichartz G, Serhan CN. Emerging roles of resolvins in the resolution of inflammation and pain.Trends Neurosci. 2011 Nov;34(11):599-609. doi: 10.1016/j.tins.2011.08.005. Epub 2011 Sep 30. Review.
  • Kantor ED, Lampe JW, Vaughan TL, Peters U, Rehm CD, White E. Association between use of specialty dietary supplements and C-reactive protein concentrations. Am J Epidemiol. 2012 Dec 1;176(11):1002-13. doi: 10.1093/aje/kws186. Epub 2012 Nov 8.
  • Levy BD, Vachier I, Serhan CN. Resolution of inflammation in asthma. Clin Chest Med. 2012 Sep;33(3):559-70. doi: 10.1016/j.ccm.2012.06.006. Epub 2012 Jul 25.
  • Miles EA, Calder PC. Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis. Br J Nutr. 2012 Jun;107 Suppl 2:S171-84. doi: 10.1017/S0007114512001560. Review.
  • Rangel-Huerta OD, Aguilera CM, Mesa MD, Gil A. Omega-3 long-chain polyunsaturated fatty acids supplementation on inflammatory biomakers: a systematic review of randomised clinical trials. Br J Nutr. 2012 Jun;107 Suppl 2:S159-70. doi: 10.1017/S0007114512001559. Review.
  • Serhan CN, Petasis NA. Resolvins and protectins in inflammation resolution. Chem Rev. 2011 Oct 12;111(10):5922-43. doi: 10.1021/cr100396c. Epub 2011 Jul 18. Review.
  • Serhan CN. Lipoxins and aspirin-triggered 15-epi-lipoxins are the first lipid mediators of endogenous anti-inflammation and resolution. Prostaglandins Leukot Essent Fatty Acids. 2005 Sep-Oct;73(3-4):141-62. Review.
  • Serhan CN. Novel omega-3-derived local mediators in anti-inflammation and resolution. Pharmacol Ther. 2005 Jan;105(1):7-21. Review.