Higher omega-3 index linked to reduced cognitive depression symptoms in heart failure patients, study finds

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Higher omega-3 levels may be linked to reduced depression symptoms in heart failure patients, according to a study recently published in the Journal of the American College of Cardiology’s Heart Failure.¹ Researchers found a correlation between high blood levels of long-chain omega-3 fatty acids, as measured by the Omega-3 Index, and improvement in social function in congestive heart failure patients who have been diagnosed with major depressive disorder. This multicenter, double-blind, placebo-controlled, parallel group randomized clinical pilot trial randomly assigned 108 subjects to receive either 2 g of a 2:1 EPA:DHA fish oil supplement (with each pill containing 400 mg EPA and 200 mg DHA), 2 g of a high-EPA supplement, or a matched placebo for 12 weeks.

Results showed that compared to placebo, levels of all omega-3 variables in red blood cells were significantly elevated in both supplement groups. Using a 36-item Short Form Health Survey, researchers measured social functioning and saw significant improvement in the EPA/DHA fish oil group. While the high-EPA group did show greater improvement compared to placebo, the difference was not statistically significant. A correlation was also found between elevated omega-3 levels from supplementation and a greater reduction in cognitive depressive symptoms based on Beck Depression Inventory-II cognitive subscales. The change in cognitive depressive symptom subscales was stronger in the high-EPA group.

It’s important to note that supplementation with omega-3s did not improve measures of overall depressive symptoms and that the improvements that did occur were not physical/somatic but related to affective cognition change. Improvement in social functioning is still important because social isolation is a cardinal symptom of major depressive disorder.

“Our findings indicate that with reasonable compliance, patients with congestive heart failure and moderate to severe major depressive disorder showed improvements in the following: 1) social function, reflected by a reduction in physical/emotional symptoms that interfered with their social activities with family, friends, neighbors, or groups; 2) feelings of control, reflected by ratings of feeling less limited from their physical and/or emotional problems; and 3) cognitive-emotional symptoms of depression,” wrote the researchers.

The researchers also state that the role of affective cognition in depression has been increasingly recognized, but there is yet an effective way to measure it. While the results were compelling, this was a pilot study, so it has its limitations and requires a larger follow-up study.

“In their larger follow-up study, I would recommend they choose just one of the supplements (probably the pure EPA product) and increase the dose and duration of the study,” commented William Harris, PhD, one of the study’s authors and co-inventor of the Omega-3 Index, in a press release. “From this study, it’s not clear to me that one supplement type was better than the other. However, linking higher blood levels of omega-3s to improved depression symptoms in people with both depression and heart failure is encouraging and hopefully leads to better treatment for their conditions.”

References:

1. Jiang, W. et al. "Long-chain omega-3 fatty acid supplements in depressed heart failure patients." JACC: Heart Failure. Published online ahead of print August 7, 2018.