From the Guidelines
Fish oil can help reduce systemic inflammation, as evidenced by its ability to produce anti-inflammatory compounds called resolvins and protectins, which can lead to improved clinical outcomes in critically ill patients. The most recent and highest quality study, published in 2024 in the journal Critical Care 1, found that parenteral nutrition (PN) formulations containing fish oil were associated with a significant decrease in hospital length of stay and a trend towards reduction in 28-day mortality, ICU length of stay, and shorter duration of mechanical ventilation. This study also reported that PN containing fish oil reduced the duration of ICU care and the rate of nosocomial infection.
The mechanisms by which fish oil exerts its anti-inflammatory effects are complex and involve the production of pro-resolution lipid mediators, such as resolvins, protectins, and maresins, which typically derive from omega-3 polyunsaturated fatty acids (PUFAs) 1. In contrast, pro-inflammatory lipid mediators, such as prostaglandins or leukotrienes, typically derive from omega-6 PUFAs. The timely resolution of inflammation is associated with more favorable clinical outcomes, and fish oil has been shown to play a role in this process.
Some key points to consider when using fish oil to reduce systemic inflammation include:
- Choosing high-quality supplements that specify EPA and DHA content
- Taking 1-3 grams of omega-3 fatty acids (EPA and DHA) daily through fish oil supplements
- Taking supplements with meals to improve absorption and reduce fishy aftertaste
- Being aware of potential mild side effects, such as fishy breath or digestive discomfort, and interactions with blood-thinning medications
- Considering food sources, such as eating fatty fish like salmon or mackerel 2-3 times weekly, as an alternative to supplements
Overall, the evidence suggests that fish oil can be a useful adjunct in reducing systemic inflammation, particularly in critically ill patients, and its use is supported by recent guidelines from the European Society for Clinical Nutrition and Metabolism (ESPEN) and the Canadian Critical Care Nutrition Organization 1.
From the Research
Effects of Fish Oil on Systemic Inflammation
- Fish oil, which is rich in omega-3 fatty acids, has been shown to have anti-inflammatory properties 2, 3.
- The omega-3 fatty acids in fish oil, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been found to reduce the production of pro-inflammatory cytokines and eicosanoids 2, 3.
- Studies have demonstrated that fish oil supplementation can decrease the levels of inflammatory markers, such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) 3, 4.
Comparison of EPA and DHA
- Some studies have suggested that DHA may have stronger anti-inflammatory effects than EPA 4, 5.
- However, other studies have found that both EPA and DHA have similar effects on reducing systemic inflammation 4, 6.
- The effects of EPA and DHA on inflammation may be mediated by different mechanisms, including the production of specialized pro-resolving lipid mediators (SPM) 5.
Clinical Implications
- Fish oil supplementation has been shown to be beneficial in reducing inflammation in various diseases, including rheumatoid arthritis, Crohn's disease, and ulcerative colitis 2.
- The anti-inflammatory effects of fish oil may also be beneficial in reducing the risk of cardiovascular disease and other conditions characterized by chronic inflammation 3, 6.
- Further research is needed to fully understand the effects of fish oil on systemic inflammation and to determine the optimal dosage and duration of supplementation 3, 4.