Omega-3 and omega-6 fatty acids, two essential polyunsaturated fats, are typically linked to anti- and pro-inflammatory effects, respectively.
A new University of Bristol study challenges this idea, revealing that omega-3s may raise certain inflammation markers, even after factoring in other health indicators like triglycerides and LDL cholesterol. This finding suggests that the link between PUFAs and inflammation may be more complex than previously believed.
Researchers studied how omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) relate to inflammation by analyzing data from two large cohorts, the Avon study (2,802 people) and the UK Biobank (12,401 people).
They used multivariable analyses to assess the relationship between PUFA intake and key inflammatory markers such as C-reactive protein (CRP), Glycoprotein acetyls (GlycA), and Interleukin 6 (IL-6).
To confirm their findings, they used various methods like Inverse-variance weighted (IVW) analysis, sensitivity tests for robustness, and Multivariable MR (MVMR) to adjust for other fats and lipids like
LDL (bad cholesterol), Triglycerides, Saturated and monounsaturated fats.
The goal? To clarify whether omega-3s and omega-6s drive inflammation in the body, or if it’s just an overlap with other dietary and genetic factors.
Researchers found that higher levels of omega-3 fatty acids were unexpectedly linked to increased inflammation in the body, based on blood biomarkers.
They also discovered that a higher omega-6 to omega-3 ratio is too much omega-6 compared to omega-3, was consistently tied to greater inflammation, challenging the long-held belief that omega-3s are always anti-inflammatory.
Omega-6 fatty acids may help prevent heart disease
They then applied two-sample Mendelian randomization (MR) to explore whether the associations were likely to be causal, not just correlational.
Dr. Daisy Crick, who is now at the University of Queensland’s Institute of Molecular Bioscience in Australia, said, “The belief that omega-3 fats lower inflammation and mitigate the risk of non-communicable diseases has led to popular diets like the Mediterranean diet and the use of supplements.”
“But the previously believed relationship that omega-3 reduces levels of inflammation may not always be correct.”
“Our findings suggest that the dietary fatty acids and inflammation relationship is more complex than previously thought, and it might be more useful to look at the balance (or ratio) between omega-6 and omega-3 in the diet.”
Dr. Hannah Jones, senior author of the study from the University of Bristol, emphasized that while the research found links between omega-3 fats and certain inflammation markers, the picture is far from complete. She noted that omega-3s may still offer dietary benefits, and because inflammation is highly complex, more research using broader biomarkers is needed before making firm conclusions about their effects.
Journal Reference
- Daisy C P Crick, Sarah L Halligan, George Davey Smith, Golam M Khandaker, and Hannah J Jones. The relationship between polyunsaturated fatty acids and inflammation: evidence from cohort and Mendelian randomization analyses. International Journal of Epidemiology. DOI: 10.1093/ije/dyaf065
