Low omega-3 index and polyunsaturated fatty acid status in patients with chronic fatigue syndrome/myalgic encephalomyelitis

Prostaglandins Leukot Essent Fatty Acids. 2018 Dec;139:20-24. doi: 10.1016/j.plefa.2018.11.006. Epub 2018 Nov 9.


Background: Several studies have suggested that low levels of omega-3 fatty acids (n-3 PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with cardiovascular risk, major depression, sleep problems, inflammation and other health-related issues. So far, however, erythrocyte PUFA status in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) has not been established. This study aimed to determine whether n-3 PUFA content and omega-3 index are associated with measures in CFS/ME patients.

Patients and methods: PUFA levels and omega-3 index were measured in 31 Spanish CFS/ME patients using the HS-Omega-3 Index method. Demographic and clinical characteristics and self-reported outcome measures were also recorded.

Results: A low mean omega-3 index (5.75%) was observed in 92.6% of the sample. Omega-3 index was inversely correlated with the AA/EPA ratio (p = 0.00002) and the BMI (p = 0.0106). In contrast, the AA/EPA ratio was positively associated with the BMI (p = 0.0038). No association for FIS-40 and PSQI measures was found (p > 0.05).

Conclusion: The low omega-3 index found in our CFS/ME patients may indicate increased risks for cardiovascular health, which should be further investigated. A low omega-3 index also suggests a pro-inflammatory state in these patients. Attempts should be made to increase the omega-3 index in CFS/ME patients, based on intervention trials assessing a potential therapeutic value.

Keywords: Cardiovascular health; Chronic fatigue syndrome; Inflammation; Myalgic encephalomyelitis; Omega-3 index; Polyunsaturated fatty acids.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Cross-Sectional Studies
  • Depressive Disorder, Major / blood*
  • Fatigue Syndrome, Chronic / blood*
  • Fatty Acids, Omega-3 / blood*
  • Female
  • Humans
  • Inflammation / blood
  • Male
  • Middle Aged
  • Pilot Projects
  • Sleep Wake Disorders / blood*


  • Fatty Acids, Omega-3