Sadly, you can't trust most news headlines about health-nutrition studies.
That's clearly the case with an epidemiological study from Denmark, which compared the self-reported diets of 3,277 people with their heart health over a 23-year period.
Occasionally, a study fails to link omega-3s from fish to a particular heart-health benefit, or finds that they only benefited a certain gender or age group.
That happened in the case of the newly reported Danish diet-health survey, whose one unusual, negative finding generated many misleading headlines.
Sadly, the media almost universally accentuated that study's main negative finding – related to men – and ignored its equally important positive outcome for women.
Omega-3s benefited women, not men; No one was helped by plant-source omega-3s
The Danish study looked only at whether fish-source and plant-source omega-3 fatty acids could protect against heart disease (Vedtofte MS et al. 2011).
It did not try to see whether omega-3s of any kind reduced the rate of “adverse cardiovascular events”, such as heart attacks and strokes.
The Danish team's major positive finding was that women with higher estimated intakes of omega-3s from fish and/or fish oil were less likely to develop coronary heart disease over two decades.
But you'd never know that from all the headlines we've seen … which ignored all prior evidence and reflected only the two negative findings:
Unlike women, men showed no benefit from higher estimated intakes of omega-3s.
Higher intakes of plant-source omega-3s were not linked to lower heart risk for men or women.
While the men in this study showed no heart benefit from any form of omega-3s, most studies show benefit among men and women alike … usually with smaller differences than those detected in this population study.
Gender-related differences in omega-3s' effects on heart health are not surprising, given the differences in how cardiovascular disease manifests in men and women.
For more on those distinctions, see “Women's Heart Problems Found Distinct from Men's.”
Fish-source omega-3s clearly help hearts
By now, the body of evidence affirming omega-3s' role in optimizing heart health and reducing heart risks approaches overwhelming status.
This evidence comes from several large, well-designed clinical trials and many dozens of epidemiological studies. This picture was affirmed by a recent evidence review (Marik PE, Varon J et al. 2009) … for an overview, see “Omega-3s Cut Heart Risks & Death Rates in Clinical Trial.”
Importantly, hundreds of lab studies show that omega-3s exert physiological effects that could – and probably do – support optimal heart and circulatory health.
Plant-source omega-3s failed for both genders
What about the fact that this study found no sign that the sole plant-source omega-3 fatty acid – a “short-chain” omega-3 called ALA – reduced heart risk in either gender?
Some studies link them to minor reductions in heart disease risks, though never to the extent seen with fish-source, “long-chain” omega-3s (EPA and DHA) … the kind we actually need to survive and thrive (Hu FB et al. 1999; Albert CM et al. 2005).
That said, the body can make essential EPA and DHA from ALA, albeit very inefficiently. ALA is the only omega-3 many people eat, and they can survive or even thrive on ALA alone if it's consumed in sufficient quantities.
The main food sources of omega-3 ALA include beans, dark leafy greens, flax or hemp seeds, walnuts, canola oil, and soy oil.
(Soy oil is a counterproductive source of omega-3 ALA, because it is very high in omega-6 fatty acids … which compete with omega-3s for absorption into our cells and are unhealthily overabundant in the standard American diet.)
While plant-form omega-3s clearly do benefit heart and overall health, the vast majority of scientific evidence favors fish-source omega-3s for both purposes.
The estimated average daily intake of omega-3s (all forms) among the study participants was 1.2 grams for women and 1.6 grams for men … which are higher than the average American's intake, unless he or she takes fish oil.
  • Albert CM, Campos H, Stampfer MJ, Ridker PM, Manson JE, Willett WC, Ma J. Blood levels of long-chain n-3 fatty acids and the risk of sudden death. N Engl J Med. 2002 Apr 11;346(15):1113-8.
  • Albert CM, Oh K, Whang W, Manson JE, Chae CU, Stampfer MJ, Willett WC, Hu FB. Dietary alpha-linolenic acid intake and risk of sudden cardiac death and coronary heart disease. Circulation. 2005 Nov 22;112(21):3232-8.
  • Arita M, Yoshida M, Hong S, et al. Resolvin E1, an endogenous lipid mediator derived from omega-3 eicosapentaenoic acid, protects against 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Proc Natl Acad Sci USA 2006;102:7671– 6.
  • Bucher HC, Hengstler P, Schindler C, Meier G. N-3 polyunsaturated fatty acids in coronary heart disease: a meta-analysis of randomized controlled trials. Am J Med. 2002 Mar;112(4):298-304.
  • Burr ML, Ashfield-Watt PA, Dunstan FD, Fehily AM, Breay P, Ashton T, Zotos PC, Haboubi NA, Elwood PC. Lack of benefit of dietary advice to men with angina: results of a controlled trial. Eur J Clin Nutr. 2003 Feb;57(2):193-200.
  • Cordain L et al. Origins and evolution of the Western diet: health implications for the 21st century. American Journal of Clinical Nutrition (2005).81:341-354.
  • De Lorgeril et al. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction; final report of the Lyon Diet Heart Study. Circulation (1999)99;779-785.
  • Deckelbaum RJ, Akabas SR. n-3 Fatty acids and cardiovascular disease: navigating toward recommendations. Am J Clin Nutr. 2006 Jul;84(1):1-2.
  • Dubnov G, Berry EM. Omega-6/omega-3 fatty acid ratio: The Israeli Paradox. World Review of Nutrition and Dietetics. (2003):92:81-91.
  • Guallar E, Hennekens CH, Sacks FM, Willett WC, Stampfer MJ. A prospective study of plasma fish oil levels and incidence of myocardial infarction in U.S. male physicians. J Am Coll Cardiol. 1995 Feb;25(2):387-94.
  • Hooper L, Thompson RL, Harrison RA, Summerbell CD, Moore H, Worthington HV, Durrington PN, Ness AR, Capps NE, Davey Smith G, Riemersma RA, Ebrahim SB. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ, doi:10.1136/bmj.38755.366331.2F (published 24 March 2006)
  • Hooper L, Thompson RL, Harrison RA, Summerbell CD, Moore H, Worthington HV, Durrington PN, Ness AR, Capps NE, Davey Smith G, Riemersma RA, Ebrahim SB. Omega 3 fatty acids for prevention and treatment of cardiovascular disease. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD003177. Review.
  • Hu FB, Stampfer MJ, Manson JE, Rimm EB, Wolk A, Colditz GA, Hennekens CH, Willett WC. Dietary intake of alpha-linolenic acid and risk of fatal ischemic heart disease among women. Am J Clin Nutr. 1999 May;69(5):890-7.
  • Lands EM. Dietary fat and health: the evidence and the politics of prevention. Annal New York Academy of Sciences (2005). 1055:179-192.
  • Lands WE. Primary prevention in cardiovascular disease: moving out of the shadows of the truth about death. Nutr Metab Cardiovasc Dis. 2003 Jun;13(3):154-64. Review.
  • Lemaitre RN, King IB, Mozaffarian D, Kuller LH, Tracy RP, Siscovick DS. n-3 Polyunsaturated fatty acids, fatal ischemic heart disease, and nonfatal myocardial infarction in older adults: the Cardiovascular Health Study. Am J Clin Nutr. 2003 Feb;77(2):319-25.
  • Leng GC, Lee AJ, Fowkes FG, et al. Randomized controlled trial of gamma-linolenic acid and eicosapentaenoic acid in peripheral arterial disease. Clinical Nutrition 1998. 17(6):265-271. (PubMed)
  • Marchioli R, Barzi F, Bomba E, et al. Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-Prevenzione. [see comments.] Circulation 2002. 105(16):1897-1903. (PubMed)
  • Marik PE, Varon J. Omega-3 dietary supplements and the risk of cardiovascular events: a systematic review. Clin Cardiol. 2009 Jul;32(7):365-72. Review.
  • Mori TA, Woodman RJ. The independent effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular risk factors in humans. Curr Opin Clin Nutr Metab Care 2006;9:95–104.
  • Nilsen DW, Albrektsen G, Landmark K, et al. Effects of a high-dose concentrate of n-3 fatty acids or corn oil introduced early after an acute myocardial infarction on serum triacylglycerol and HDL cholesterol. Am J Clin Nutr 2001. 74(1):50-56. (PubMed)
  • Okuyama H et al. Dietary fatty acids—the n-6/n-3 balance and chronic elderly diseases: excess linoleic acic and relative n-3 deficiency syndrome seen in Japan Prog Lipid. Res (1997); 35(4):409-457.
  • Sacks FM, Stone PH, Gibson CM, et al. Controlled trial of fish oil for regression of human coronary atherosclerosis. HARP Research Group. Journal of the American College of Cardiology 1995. 25(7):1492-1498. (PubMed)
  • Simon JA, Hodgkins ML, Browner WS, Neuhaus JM, Bernert JT Jr, Hulley SB. Serum fatty acids and the risk of coronary heart disease. Am J Epidemiol. 1995 Sep 1;142(5):469-76.
  • Simopoulos AP, Leaf A, Salem Jr N. Workshop statement on the essentiality of and recommended dietary intakes for omega-6 and omega-3 fatty acids. Prostaglandins, Leukot Essential Fatty Acids (2000) 63:119-121.
  • Simopoulus, AP and Cleland LG. Omega-6/Omega-3 Essential Fatty acid ratio: the scientific evidence. World Review of Nutrition and Dietetics. (2003): 92:1-174.
  • Siscovick DS, Raghunathan TE, King I, Weinmann S, Wicklund KG, Albright J, Bovbjerg V, Arbogast P, Smith H, Kushi LH, et al. Dietary intake and cell membrane levels of long-chain n-3 polyunsaturated fatty acids and the risk of primary cardiac arrest. JAMA. 1995 Nov 1;274(17):1363-7.
  • Vedtofte MS, Jakobsen MU, Lauritzen L, Heitmann BL. Dietary {alpha}-linolenic acid, linoleic acid, and n-3 long-chain PUFA and risk of ischemic heart disease. Am J Clin Nutr. 2011 Aug 24. [Epub ahead of print]
  • Wang C, Chung M, Balk E, Kupelnick B, DeVine D, Lawrence A, et al. Effects of omega-3 fatty acids on cardiovascular disease. Rockville,MD, USA: Agency for Healthcare Research and Quality, 2004. Evidence Report/Technology Assessment 94. Accessed online March 26, 2006 at = hstat1a.chapter.38290.
  • Wang C, Harris WS, Chung M, et al. n-3 Fatty acids from fish or fish-oil supplements, but not -linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review. Am J Clin Nutr 2006;84:5–17.