Fish Oil May Improve Heart Function

Published: September 28, 2012

In a placebo-controlled study involving 21 healthy men and women, supplementation with fish oil (DHA plus EPA—the 2 main oils in fish oil) improved heart muscle efficiency. The subjects received 2 g/day DHA + 3 g/day EPA or placebo for a period of 6 weeks. The fish oil group had increased heart stroke volume (SV) and cardiac output (CO). The authors of the study concluded "DHA + EPA-induced increases in SV and CO imply that dietary supplementation with these fatty acids can increase oxygen delivery during exercise, which may have beneficial clinical implications for individuals with cardiovascular disease and reduced exercise tolerance."1

Another study using fish oil in athletes showed "five weeks of supplementation with fish oil improved cardiovascular function and reduced cardiovascular risk factors, but did not improve endurance performance or recovery in elite Australian Rules footballers."2

Small heart is a problem in CFS. Small heart syndrome has previously been reported as neurocirculatory asthenia, associated with a small heart shadow on a chest x-ray. This is characterized as weakness or fatigue even after ordinary exertion, palpitation, shortness of breath, and fainting, resembling patients with chronic fatigue syndrome (CFS).

In the study, 56 patients (<50 years of age) with CFS, and 38 control subjects were tested. Chest x-ray, echocardiography, and physical examinations were performed.

Small heart was more prevalent in the CFS group (61%) than in the control group (24%). In CFS patients with a small heart (n = 34), narrow chest (88%), orthostatic dizziness (44%), foot coldness (41%), pretibial pitting edema (32%), and mitral valve prolapse (29%), were all significantly more prevalent than in the control group, and also in the CFS patients without small heart syndrome. Echocardiographic examination demonstrated significantly smaller values of both the left ventricular (LV) end-diastolic dimensions and end-systolic, and stroke volume and cardiac indexes in CFS with a small heart, as compared with control subjects with a normal heart size (42% < cardiothoracic ratio < 50%).

"Small heart syndrome may contribute to the development of CFS as a constitutional factor predisposing to fatigue, and may be included in the genesis of CFS."3

Heart function can be dramatically improved nutritionally (see Low ATP Energy Levels in Fibromyalgia).


1"Omega-3 fatty acid supplementation enhances stroke volume and cardiac output during dynamic exercise," Walser B, Stebbins CL, Eur J Appl Physiol, 2008 June 18; [Epub ahead of print]

2"DHA-rich fish oil lowers heart rate during submaximal exercise in elite Australian Rules footballers," Buckley JD, Howe PR, et al, J Sci Med Sport, 2008 June 12; [Epub ahead of print]

3Small Heart Syndrome in Patients with Chronic Fatigue Syndrome. Journal: Clin Cardiol. 2008 Jul 17;31(7):328-333. [Epub ahead of print]. Authors: Miwa K, Fujita M. NLM Citation: PMID: 18636530

Jacob Teitelbaum, MD

is one of the world's leading integrative medical authorities on fibromyalgia and chronic fatigue. He is the lead author of eight research studies on their effective treatments, and has published numerous health & wellness books, including the bestseller on fibromyalgia From Fatigued to Fantastic! and The Fatigue and Fibromyalgia Solution. His newest book (June 10, 2024) is You Can Heal From Long COVID. Dr. Teitelbaum is one of the most frequently quoted fibromyalgia experts in the world and appears often as a guest on news and talk shows nationwide including Good Morning America, The Dr. Oz Show, Oprah & Friends, CNN, and Fox News Health.

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