C-reactive protein (CRP) is a globular protein whose levels rise in the presence of inflammation. Persistently elevated CRP is associated with an increased risk of heart attack and stroke and is often used as a marker of low-grade, chronic inflammation.
Multiple observational studies have examined the relationship between omega-3 fatty acid status and CRP levels. A study published in the European Journal of Clinical Nutrition (epub ahead of print April 8, 2009) evaluated omega-3 fatty acid levels and CRP concentrations in 124 adults and found an inverse relationship between the two—higher omega-3 levels were associated with lower CRP.
Larger population studies report similar findings. Research published in Atherosclerosis (201, no. 1, November 2008, pages 184–191) examined dietary omega-3 intake and CRP levels in 14,191 adults aged 40 to 69. Omega-3 consumption was inversely associated with CRP levels, with the relationship appearing more pronounced in higher-risk groups, such as male smokers. The authors noted that smaller subgroup sizes limited firm conclusions in some populations, but the overall trend remained consistent.
Comparable results have also been reported in other cohorts. Studies published in the American Journal of Clinical Nutrition (2006; 84(1):223–229) and Nutritional Research (2008; 28(5):309–314) likewise found inverse relationships between omega-3 fatty acid intake and CRP levels.
Taken together, these findings are consistent with a broader body of research linking omega-3 fatty acids with inflammatory pathways. Since CRP reflects sustained, low-grade inflammation, it is biologically plausible that higher omega-3 intake would be associated with lower CRP levels. However, these studies are observational in nature and describe associations rather than cause-and-effect relationships.
