Yet again, many media outlets have failed to do their homework, and misled millions of readers.
Last time it was a weak, widely disputed study on omega-3s and prostate cancer (see “Fishy Prostate News”).
This time, sensation-seeking headlines implied that new proof found omega-3s useless maintaining aging people's memory or thinking capacity.
News editors worldwide did their readers a disservice, with breathless headlines that slanted the significance of one study among many.
Probably, the tendency for editors to plaster distorted, alarmist headlines on health articles stems from publishers' desire to attract more readers, in order to boost ad revenues.
We understand the commercial pull pushing this phenomena, but still deplore its effect on readers given whiplash by contradictory, often bogus articles in mainstream (and alternative) media.
In this case, the misleading headlines relate to an epidemiological (diet-health) study in American women.
Despite misleading headlines, omega-3s clearly help brain health
Judging by headlines at major media outlets, the results of just one non-clinical study prove that higher intakes of omega-3 fatty acids don't protect against cognitive decline.
However, if you read far enough into the media reports, the researchers involved say they believe that their findings do not prove that omega-3s have no brain benefits.
In fact, most of the published research suggests that over time, the long chain omega-3 fatty acids in seafood (EPA and DHA) help sharpen memory and thinking, and help prevent or delay normal age-related dementia.
There's some evidence that omega-3s might help prevent or delay Alzheimer's disease in people with particular APO gene profiles … but there's none showing that omega-3s exert major preventive or therapeutic effects against Alzheimer's.
Omega-3s enjoy ample evidence of dementia-prevention potential, from most of the many epidemiological studies and some of the few clinical trials.
Clinical trials are the most reliable studies, but there haven't been many that tested fish oil supplements on age-related cognitive (memory and thinking) declines.
It's critical to note that all of the trials conducted to date were probably too small and/or brief to allow firm conclusions.
As the lead author of the longest-ever clinical trial said, “It is important to keep in mind that poor cognitive function can take many years to develop and although this is the longest trial of its kind ever conducted, it may be that it was not long enough for any beneficial effects to be detected among this healthy cohort [group] of older people”.
Likewise, the lead author of the new study – Eric Ammann of the University of Iowa –  exrpessed caution to USA Today, saying, “Our study is not necessarily the definitive” answer on omega-3 fatty acids and age-related brain decline.
Ammann added that their results should not be over-interpreted: “We do not recommend that people change their diet based on these results. Researchers continue to study the relationship between omega-3s and the health of the heart, blood vessels, and brain.”
Details of the new epidemiological study in women 
The new epidemiological study was conducted by researchers from the University of Iowa, Iowa City, the University of South Dakota, and Wake Forest School of Medicine.
They examined omega-3 blood levels and the outcomes on brain tests among 2,157 women with normal cognitive health.
The women volunteered for a six-year clinical trial of postmenopausal hormone replacement therapy (HRT).
The women were given an initial blood test and battery of memory and cognition (thinking and verbal capacity) tests, and repeated the cognitive testing once a year for six years.
Ammann's team looked for links between women's blood levels of omega-3s (DHA and EPA) and their memory and cognitive functions.
At the trial's start, the brain tests detected no cognitive differences between women with high versus low omega-3 blood levels.
Likewise, after the six-year trial ended, no links were detected between the rate or extent of a woman's age-related cognitive decline and her omega-3 blood levels.
Study has limitations, and occurs within a generally positive context
First, no epidemiological study can prove a cause-and-effect relationship – or lack of one – between one aspect of a person's diet and their health outcomes.
But the study's most severe limitation was its reliance just a single test of the women's omega-3 blood levels, at the start of the trial.
In other words, the researchers' conclusions assume that the women's omega-3 blood levels remained fairly steady over six years … which seems unlikely.
We take these findings with a grain of salt, given the study's limitations and the very substantial existing evidence that higher omega-3 intakes aid memory and cognition.
Indeed, Ammann noted that the results of the study should not be taken too seriously: “We do not recommend that people change their diet based on these results. Researchers continue to study the relationship between omega-3s and the health of the heart, blood vessels, and brain.”
  • Ammann EM, Pottala JV, Harris WS, Espeland MA, Wallace R, Denburg NL, Carnahan RM, Robinson JG. Omega-3 fatty acids and domain-specific cognitive aging: Secondary analyses of data from WHISCA. Neurology. 2013 Sep 25. [Epub ahead of print]
  • Sinn N, Milte CM, Street SJ, Buckley JD, Coates AM, Petkov J, Howe PR. Effects of n-3 fatty acids, EPA v. DHA, on depressive symptoms, quality of life, memory and executive function in older adults with mild cognitive impairment: a 6-month randomised controlled trial. Br J Nutr. 2012 Jun;107(11):1682-93. doi: 10.1017/S0007114511004788. Epub 2011 Sep 20.
  • Tan ZS, Harris WS, Beiser AS, Au R, Himali JJ, Debette S, Pikula A, Decarli C, Wolf PA, Vasan RS, Robins SJ, Seshadri S. Red blood cell ω-3 fatty acid levels and markers of accelerated brain aging. Neurology. 2012 Feb 28;78(9):658-64. doi: 10.1212/WNL.0b013e318249f6a9