The evidence that omega-3s help heart and overall health is overwhelming.
This remains true despite the impression left by lazy media reports and their inaccurate headlines.
Because bad news sells better than good, coverage of omega-3/heart studies often focuses on any negative findings ... and omits positive ones.
Worse, reporters almost invariably miss or ignore the serious flaws that experts have seen in virtually every negative study.
As in many areas of medical research, there's been little research on the effects of omega-3s in women … especially postmenopausal women.
A new study adds valuable information about that. Thankfully, it's more reliable than most … as we'll explain before we review its encouraging findings.
Challenges for omega-3 studies … and other nutrition-health research
Most studies on the health effects of foods or nutrients – such as seafood-source omega-3s – rely on participants' answers to diet surveys.
But people often report eating healthier than they actually do … and by their nature, studies like these can't prove a cause-effect relationship between omega-3 intakes and health outcomes.
The “gold standard” is a high-quality clinical trial – double-blind, randomized, and placebo-controlled – in a large number of people, lasting one year or more.
Controlled clinical studies are costly and hard to conduct, so relatively few have been done.
The next best thing is a study in which researchers measure people's blood levels of omega-3s (and other fats) over time and compare those with the participants' health outcomes over time.
That method describes a new study that found diets rich in omega-3s benefit post-menopausal women's heart health substantially.
Omega-3s linked to sharply lower heart risk among post-menopausal women
The new “case vs. control” study comes from Boston's Tufts University, Seattle's Fred Hutchinson Cancer Research Center, and universities in Australia (Matthan NR et al. 2014).
The scientists examined blood tests and medical records from 2,448 postmenopausal women between the ages of 50 and 79 who participated in the famed Women's Health Initiative study.
Out of the total, 1,224 women (cases) had coronary heart disease (CHD) and 1,224 (controls) were free of heart disease.
Importantly, the women in the control group were selected to match the age, enrollment date, and race/ethnicity of the women in the case group.
The scientists compared the women's actual omega-3 blood levels with their heart-health status, with results that support the value of seafood:
- No single saturated fat was linked to heart disease.
- Higher total saturated fat levels were linked to heart disease, modestly.
- No link was found between the sole plant-source omega-3 fat (ALA) and heart risk.
- Higher levels of the three seafood-source omega-3 fats (EPA, DHA, and DPA) were linked to sharply lower risk (27 to 44 percent reduction).
- No link was found between heart disease and the polyunsaturated omega-6 fat (LA) that abounds in soy, corn, cottonseed, safflower*, and sunflower oils*.
- Higher levels of two omega-6 polyunsaturated fats were linked to heart disease ... both are produced in the body from the omega-6 fat (LA) in the vegetable oils listed above.
*So-called “high-oleic” safflower and sunflower oils are not high in omega-6 fats. Instead, they're high in the same monounsaturated fat (oleic acid) that predominates in olive, canola, and macadamia nut oils.
As the authors concluded, “These results confirm the cardioprotective effect of very long-chain omega-3 fatty acids [the kind found only in seafood] and support current recommendations for regular fish consumption.” (Matthan NR et al. 2014)
The results also support research linking the average American's very high intake of omega-6-rich vegetable oils to increased heart and cancer risks.
- Lu Y, Vaarhorst A, Merry AH, Dollé ME, Hovenier R, Imholz S, Schouten LJ, Heijmans BT, Müller M, Slagboom PE, van den Brandt PA, Gorgels AP, Boer JM, Feskens EJ. Markers of endogenous desaturase activity and risk of coronary heart disease in the CAREMA cohort study. PLoS One. 2012;7(7):e41681. doi: 10.1371/journal.pone.0041681. Epub 2012 Jul 23.
- Matthan NR, Ooi EM, Van Horn L, Neuhouser ML, Woodman R, Lichtenstein AH. Plasma phospholipid fatty acid biomarkers of dietary fat quality and endogenous metabolism predict coronary heart disease risk: a nested case-control study within the Women's Health Initiative observational study. J Am Heart Assoc. 2014 Aug 13;3(4). pii: e000764. doi: 10.1161/JAHA.113.000764.
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