December 29, 2020

Recent studies add to the list of health benefits associated with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are omega-3 long chain polyunsaturated fatty acids occurring in fish and the algae they consume. Optimal omega-3 fatty acid intake has been associated with cardiovascular, brain and other benefits, and continues to be the subject of nutritional research.

On October 10, 2020, the journal Atherosclerosis reported the findings of a secondary analysis of a trial that involved 64 men and women with symptoms of cardiovascular disease who underwent coronary CT angiography (CTA). Blood samples were analyzed for red blood cell membrane fatty acid composition as a biomarker of tissue fatty acid composition. CTA images were analyzed for pericoronary adipose tissue attenuation (PCAT), which is associated with increased inflammation.

“PCAT attenuation in computed tomography has previously been proposed as a novel marker of coronary inflammation,” authors Daniel O. Bittner, DO, of Friedrich-Alexander University Erlangen-Nürnberg and colleagues wrote. “The mechanism of action is explained by the development of atherosclerosis itself, in which vascular inflammation promotes atherosclerotic plaque formation. As there is communication of inflammatory mediators between vasculature and perivascular adipose tissue, perivascular fat composition may be altered due to adjacent vascular inflammation. This change in perivascular fat composition can subsequently be detected by a change in local attenuation.”

Subjects in the current analysis were divided into high or low PCAT attenuation values. The group that had low PCAT attenuation had higher median levels of EPA, suggesting a different composition of pericoronary fat tissue and less coronary inflammation.

The analysis was the first to use noninvasive imaging to provide evidence for an association between EPA and PCAT composition. Dr Bittner and colleagues concluded that the data supports the beneficial effects of EPA and helps explain the survival advantage associated with the fatty acid in larger studies.

Another recently published report, which appeared on November 12, 2020 in Prostaglandins, Leukotrienes and Essential Fatty Acids, described a trial which found that men who received DHA-enriched fish oil experienced increases in testosterone compared to men who received a placebo.

The trial included 61 overweight and obese men and women who received capsules that contained a corn oil placebo or fish oil that provided 120 mg EPA plus 860 mg DHA per day for 12 weeks. Fasting blood samples collected before and after the treatment period were analyzed for red blood cell membrane fatty acid composition, testosterone, lipids and other factors.

At the end of the trial, participants who received fish oil had significantly higher red blood cell membrane EPA and DHA levels compared to the control group. Men experienced an average increase of 1.95 nanomoles per liter testosterone compared to the placebo group, which was associated with red blood cell membrane increases in DHA levels. While the authors of the report recommend further research, they remark that “Dietary DHA may potentially be a beneficial treatment or adjunct treatment for men with mild hypogonadism for whom testosterone is not clinically indicated.”

These studies suggest potential new indications for omega-3 fatty acids in human nutrition. Other studies continue to add evidence to previously established benefits and support regular dietary intake of EPA and DHA.