July 12, 2016

Omega-3s linked with lower risk of fatal heart attacks

At a Glance

  • Researchers found that blood levels of seafood- and plant-based omega-3 fatty acids were associated with a lower risk of dying from heart attacks.
  • The findings suggest that diets rich in omega-3 fatty acids may benefit heart health.
Man happily eating a salmon salad Diets rich in foods that contain high levels of omega-3s, such as salmon, may help the heart.Digital Vision/Thinkstock

Omega-3 fatty acids (omega-3s) are a group of molecules that have many important functions in the body. These include blood clotting, muscle activity, digestion, fertility, and brain development.

There are several types of omega-3s, some of which must come from the diet. Eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) are found in seafood, including fatty fish (such as salmon, tuna, and trout) and shellfish (such as crab, mussels, and oysters). Alpha-linolenic acid (ALA) is found in leafy green vegetables, nuts, and some vegetable oils, such as canola, soybean, and flaxseed. Omega-3s are also available as dietary supplements.

Past research suggests that omega-3s may help protect against heart disease. However, the results have been inconclusive. These variable findings may be because some studies used self-reported dietary information rather than directly measuring omega-3 levels. An international team led by Drs. Dariush Mozaffarian and Liana C. Del Gobbo at Tufts University set out to directly examine the relationship between levels of omega-3s in the body and the onset of heart disease. The research was supported by several NIH components. Results appeared online on June 27, 2016, in JAMA Internal Medicine.

The scientists combined findings from 19 large studies. Together, these included more than 45,000 healthy people from 16 countries (United States, Australia, Costa Rica, Finland, France, Germany, Ireland, Israel, Italy, Norway, Singapore, the Soviet Union, Spain, Sweden, Switzerland, and the United Kingdom). The participants had a median age of 59 years at the start of the studies, and 63% were male.

Blood or tissue levels of several seafood- and plant-derived omega-3s were measured in each study. During a median of 10 years of follow up, almost 8,000 participants developed a first heart attack, including about 7,200 nonfatal heart attacks and 2,800 deaths.

The researchers found that EPA, DPA, DHA, and ALA were all associated with a lower risk of fatal heart disease. DPA was also associated with a lower risk of total heart disease, whereas ALA, EPA, and DHA weren’t. The group didn’t find any associations between omega-3s and nonfatal heart attacks. These relationships held across participant’s age, sex, diabetes status, and use of aspirin or cholesterol-lowering medications.

“Our results lend support to the importance of fish and omega-3 consumption as part of a healthy diet,” Mozaffarian says.

The researchers are conducting further work to understand how omega-3s and other fatty acids in the diet might affect the risk of developing diabetes, obesity, cancers, and other conditions.

—by Carol Torgan, Ph.D.

Related Links

Reference: ω-3 Polyunsaturated Fatty Acid Biomarkers and Coronary Heart Disease: Pooling Project of 19 Cohort Studies. Del Gobbo LC, Imamura F, Aslibekyan S, Marklund M, Virtanen JK, Wennberg M, Yakoob MY, Chiuve SE, Dela Cruz L, Frazier-Wood AC, Fretts AM, Guallar E, Matsumoto C, Prem K, Tanaka T, Wu JH, Zhou X, Helmer C, Ingelsson E, Yuan JM, Barberger-Gateau P, Campos H, Chaves PH, Djoussé L, Giles GG, Gómez-Aracena J, Hodge AM, Hu FB, Jansson JH, Johansson I, Khaw KT, Koh WP, Lemaitre RN, Lind L, Luben RN, Rimm EB, Risérus U, Samieri C, Franks PW, Siscovick DS, Stampfer M, Steffen LM, Steffen BT, Tsai MY, van Dam RM, Voutilainen S, Willett WC, Woodward M, Mozaffarian D; Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Fatty Acids and Outcomes Research Consortium (FORCe). JAMA Intern Med. 2016 Jun 27. doi: 10.1001/jamainternmed.2016.2925. [Epub ahead of print]. PMID: 27357102.

Funding: NIH’s National Heart, Lung, and Blood Institute (NHLBI), National Cancer Institute (NCI), National Human Genome Research Institute (NHGRI), National Institute on Aging (NIA), National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institute of Neurological Disorders and Stroke (NINDS), National Institute on Minority Health and Health Disparities (NIMHD), and National Center for Research Resources (NCRR); Commission of the European Communities; Directorate General-V Europe against Cancer; Dutch Ministry of Health; Ulster Cancer Foundation; Milk Intervention Board; Cancer Research Switzerland; Swiss National Science Foundation; The Spanish Fondo de Investigaciones Sanitarias; Ministry of Science and Education; German Federal Health Office; Medical Research Council; Cancer Research UK; Italian Ministry of Health; Academy of Finland; VicHealth; Cancer Council Victoria; Australia’s National Health and Medical Research Council; Cancer Council Victoria; Swedish Cancer Society; Swedish Research Council; Fondation pour la Recherche Médicale; Caisse Nationale Maladie des Travailleurs Salariés; Direction Générale de la Santé; MGEN; Institut de la Longévité; Conseils Régionaux d’Aquitaine et Bourgogne, Fondation de France; Ministry of Research–Institut National de la Santé et de la Recherche Médicale Programme Cohortes et collections de données biologiques;  Agence Nationale de la Recherche; Fondation Plan Alzheimer; Caisse Nationale pour la Solidarité et l’Autonomie; Scottish Health Department Chief Scientist Organization; British Heart Foundation; FP Fleming Trust; Singapore National Medical Research Council; Swedish Research Council for Health; Working Life and Welfare; Uppsala City Council; and the Swedish Research Council.