If you eat fish, rather than take a fish-oil supplement, is there more likely to be a benefit? There's more than a suggestion that this is indeed the case. Verena J Matthew/iStockphoto hide caption toggle caption Verena J Matthew/iStockphoto The Salt Why Can't Fish Oil Supplements Keep Our Brains Sharp? September 26, 2013 Contrary to earlier studies, new research suggests that omega-3 fatty acids may not stave off cognitive decline. We look at why this is hard to pin down — and examine the body of evidence that finds supplements may not be as effective as eating fish meals in protecting brain health.