Omega-3 Polyunsaturated Fatty Acids Improves Indices of Heart Rate Variability

by | Oct 26, 2018 | 2018, Cardiovascular Health, Omega - 3

Written by Angeline A. De Leon, Staff Writer. A three-month supplementation with 2 grams of marine n-3 PUFA improved vagal modulation of the heart and significantly decreased heart rate in the fifty-six participating patients on chronic dialysis.

cardiovascular healthThe autonomic nervous system (ANS) serves as the link between the brain and various parts of the body. When nerves of the autonomic system become damaged, a condition called autonomic dysfunction (dysautonomia) may occur. Cardiac autonomic dysfunction is characterized by excessive activity of the sympathetic system (associated with fight-or-flight mode) and/or underactivity of the parasympathetic system (associated with rest and relaxation) and is associated with abnormal heartbeat 1. While heart rate represents a measure of baseline autonomic tone (background rate of ANS activity), heart rate variability (HRV), a measure of the beat-to-beat variability in heart rate, provides a measure of ANS modulation of heart rate 2. HRV, viewed as a biomarker of general health 3, is used to evaluate cardiac autonomic dysfunction 4, and in patient populations, lower HRV is linked to higher mortality rates 5,6. Research studies suggest that intake of omega-3 polyunsaturated fatty acids (PUFAs) may be associated with cardio-protective and antiarrhythmic effects 7,8, however, the effects of PUFA supplementation on HRV are unclear. While some studies involving patients with coronary heart disease suggest that PUFAs may improve HRV 9,10, others report no significant effects of omega-3 supplementation on HRV 11,12. In a 2018 study 13 published in Nutrients, researchers examined the effects of omega-3 PUFA intake on the HRV of patients on chronic dialysis, a population in whom cardiac autonomic dysfunction is common 14.

A total of 85 patients on chronic dialysis (mean age = 62.3 years) were enrolled in a randomized, double-blind, placebo-controlled trial in which they were randomized to receive 2 g of omega-3 PUFAs (1 g EPA, 1 g DHA) or an identical olive oil placebo daily for three months. Normal dietary intake of fish was maintained during the study, however, fish oil supplements were restricted eight weeks prior to treatment. At baseline and at the end of three months, venous blood samples were collected to determine lipid profile and a 48-h Holter recording (cardiac monitoring) was obtained for HRV analyses.

Data indicated that while no significant between-group differences were evident for overall HRV and plasma lipid profile, supplementation with omega-3 PUFAs was associated with a significant increase in SDNNi (representing average variability due to cycles shorter than 5 minutes) (27.5 +/- 12.0 ms to 28.6 +/- 12.3 ms), while controls demonstrated a decrease (29.5 +/- 15.4 ms to 28.0 +/- 13.9 ms) (p = 0.03). In addition, individuals in the omega-3 PUFA group showed a significant increase in mean RR-interval (time between two successive heartbeats), corresponding to a reduction of 2.5 beats per minute in heart rate (p = 0.04).

While omega-3 supplementation failed to change measures of overall HRV and serum lipid profile, its effects on RR-interval, an index of cardiac autonomic control 10, and SDNNi, indicative of improved vagal modulation, appear promising for individuals with cardiac autonomic dysfunction. One limitation of the study may be the generality of the eligibility criteria for patients (at least 18 years of age and on dialysis treatment for longer than 3 months), which led to a highly heterogenous study population in the present trial. Major strengths of the study, however, include the employment of a randomized controlled trial design and the use of 24-h HRV vs. short-term HRV, which is thought to have lower relative prognostic power for morbidity 15. 

Source: Rantanen JM, Riahi S, Johanson MB, et al. Effects of marine n-3 polyunsaturated fatty acids on heart rate variability and heart rate in patients on chronic dialysis: a randomized controlled trial. Nutrients. 2018; 10: 1313. DOI:10.3390/nu10091313.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

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Posted October 26, 2018.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

References:

  1. Franciosi S, Perry FK, Roston TM, Armstrong KR, Claydon VE, Sanatani S. The role of the autonomic nervous system in arrhythmias and sudden cardiac death. Autonomic Neuroscience. 2017;205:1-11.
  2. Scalvini S, Volterrani M, Zanelli E, et al. Is heart rate variability a reliable method to assess autonomic modulation in left ventricular dysfunction and heart failure?: Assessment of autonomic modulation with heart rate variability. International journal of cardiology. 1998;67(1):9-17.
  3. Thayer JF, Åhs F, Fredrikson M, Sollers III JJ, Wager TD. A meta-analysis of heart rate variability and neuroimaging studies: implications for heart rate variability as a marker of stress and health. Neuroscience & Biobehavioral Reviews. 2012;36(2):747-756.
  4. Malik M, Bigger JT, Camm AJ, et al. Heart rate variability: Standards of measurement, physiological interpretation, and clinical use. European heart journal. 1996;17(3):354-381.
  5. Suzuki M, Hiroshi T, Aoyama T, et al. Nonlinear measures of heart rate variability and mortality risk in hemodialysis patients. Clinical Journal of the American Society of Nephrology. 2012;7(9):1454-1460.
  6. Badarau S, Siriopol D, Drugus D, et al. Electrocardiogram abnormalities and heart rate variability in predicting mortality and cardiovascular events among hemodialyzed patients. International urology and nephrology. 2015;47(10):1703-1708.
  7. De Caterina R. n–3 fatty acids in cardiovascular disease. New England Journal of Medicine. 2011;364(25):2439-2450.
  8. Saravanan P, Davidson NC, Schmidt EB, Calder PC. Cardiovascular effects of marine omega-3 fatty acids. The Lancet. 2010;376(9740):540-550.
  9. Villa B, Calabresi L, Chiesa G, Risè P, Galli C, Sirtori CR. Omega-3 fatty acid ethyl esters increase heart rate variability in patients with coronary disease. Pharmacological research. 2002;45(6):475-478.
  10. Nodari S, Metra M, Milesi G, et al. The role of n-3 PUFAs in preventing the arrhythmic risk in patients with idiopathic dilated cardiomyopathy. Cardiovascular drugs and therapy. 2009;23(1):5-15.
  11. Hamaad A, Lee WK, Lip GY, MacFadyen RJ. Oral omega n3-PUFA therapy (Omacor) has no impact on indices of heart rate variability in stable post myocardial infarction patients. Cardiovascular drugs and therapy. 2006;20(5):359-364.
  12. Carney RM, Freedland KE, Stein PK, et al. The Effect of Omega-3 Fatty Acids on Heart Rate Variability in Depressed Patients With Coronary Heart Disease. Psychosomatic medicine. 2010;72(8):748.
  13. Rantanen J, Riahi S, Johansen M, Schmidt E, Christensen J. Effects of marine n-3 polyunsaturated fatty acids on heart rate variability and heart rate in patients on chronic dialysis: A randomized controlled trial. Nutrients. 2018;10(9):1313.
  14. Carreira MAM, Nogueira AB, Pena FM, et al. Detection of autonomic dysfunction in hemodialysis patients using the exercise treadmill test: the role of the chronotropic index, heart rate recovery, and RR variability. PloS one. 2015;10(6):e0128123.
  15. Shaffer F, Ginsberg J. An overview of heart rate variability metrics and norms. Frontiers in public health. 2017;5:258.