The new research was well-designed and had a strong number of people in it. An active researcher from UCLA (Dr. Zaldy Tan) looked omega three red blood cell levels in 1,575 people who averaged 67 years old. This established a baseline and it's important to know that Red blood cell levels represent a good look at omega three intake average, not just a one moment picture.
What happened after 3 months were a battery of mental tests and an MRI to look at both brain function and size. Those with the highest levels of omega 3s had the best results on tests of mental function AND had less age-related brain shrinking! While this does NOT prove exactly what is going on, but it does say that there is a positive correlation with something that should matter to all of us.
The question now becomes, how much fish do we need or are supplements best? What levels are needed to get this result and should the study be broadened (this was a Framingham group and they were largely white study subjects so more study may be needed with a broader population). Generally, you should know that Omega-3 fatty acids are found in ocean fish (tuna and salmon) and some plant oils (such as flaxseed). They are ESSENTIAL fatty acids that you body can't make.
Prior reasonable research has shown that eating fish 3 times a week has significant health benefits and that two of the important chemicals (and best known) are EPA (eicosapentaenoic acid) and DHA (docosahexanoic acid). Both of these relate to alpha-linolenic acid. There are at least 11 n-3 fatty acids in nature. The FDA did give a qualified health claim for reducing coronary heart disease in 2004.
Much research has noted an anti-inflammatory effect of these substances. If you chose to go the supplement root, you will bump into GRAS (Generally Recognized as Safe) as a term. The GRAS for EPA/DHA was 4.4 grams and 2.2 grams respectively in one study. Beyond your brain, one large study (more than 18,000 people) in the Lancet in 3/2007 used a 1.8 gram daily dose of E-EPA over 5 years plus or minus a statin type medicine and the E-EPA has a better result in heart function and decreased non-fatal heart events as well. It's interesting to note that few of the people in this new study used supplements, but actually ate more fish! Clearly there are decided health benefits to doing this.
The study can be found in the February 28 issue of Neurology (Tan, Z, et al.). Talk to your doctor to see how much and what form of Omega three would be best for you!