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30 June 2017 - Nutraingredients - Eating more polyunsaturated fats linked to less inflammation in patients with existing heart disease

Tim Cutcliffe

Cardiovascular patients with low polyunsaturated fatty acid (PUFA) intake suffer from higher inflammation levels, according to a recent study in Nutrition.

The research, involving patients with existing cardiovascular disease (CVD), found that intakes of both omega-3 and omega-6 fatty acids individually, as well as total PUFA, were inversely associated with certain inflammatory markers.

“Omega-3 and omega-6 FA intakes are inversely associated with inflammatory biomarkers among CVD patients,” concluded the researchers from Sao Paolo University, the Heart Hospital and  Dante Pazzanese Institute of Cardiology, both also from the same city.

It is widely recognised that the most CVD involves an inflammatory process called atherosclerosis, where artery walls become thickened by deposits of fatty plaque.

During inflammation, the body produces molecules such as C-reactive protein (CRP) and interleukins (ILs). Previous research suggests CRP is an independent predictor of CVD, while IL-1ß, IL-6, IL-8, IL-10 and IL-12 are commonly used inflammatory biomarkers.

The research team found, “In this cross-sectional study of dietary FAs and inflammatory biomarkers, among patients in secondary prevention of CVD, we observed that omega-3 and omega-6 intake was inversely related to CRP, IL-1ß, IL-10, and IL-12 levels and PUFA intake was inversely related to CRP and IL-1ß levels.”

Short-chain omega-3

Most previous studies linking omega-3 to lower inflammatory markers have involved long-chain eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA), while the anti-inflammatory benefits of alpha-linolenic acid (ALA) have tended to be overlooked.  The omega-3 source in this study was primarily from ALA, reflecting the Brazilian diet, which averages 1.7 grams / day of ALA.  

The results, indicating that ALA (a short-chain PUFA) intake is associated with reduced levels of inflammation, are consistent with the findings of an earlier review , previously reported by NutraIngredients.  

Omega-6 also anti-inflammatory?

The researchers were somewhat surprised to find that, “There was an inverse association between omega-6 and plasma CRP levels and no impact of n6/n3 PUFA ratio on inflammatory biomarkers levels.”

The majority of research involving omega-6 PUFAs have shown a pro-inflammatory association with higher intake. However, some animal studies and one in Japanese humans have found no effect of higher omega-6/ omega-3 intake ratio on inflammation, similar to the current study.  

Inconsistency between findings from this research and the majority of previous studies may depend on the baseline omega-6/ omega-3 ratio of individual study populations.

The study findings add to evidence that short-chain omega-3 intake, as well as EPA and DHA, may be linked to inflammation severity in heart disease.

However, large, well-controlled intervention trials are required to establish the use of dietary modifications in PUFA intake for reducing inflammation in secondary prevention of cardiovascular events.