Scientists have suspected for some time that Omega-3 fatty acids — a common compound found in fish oil, grass-fed livestock, walnuts, flaxseeds, and beans — has a beneficial effect on brain health (including positive effects on cognition, behavior, and mood). And in fact, it's becoming increasingly used as a dietary supplement among the elderly as a way to stave off the effects of neurodegenerative disorders like Alzheimer's. But what hasn't been certain is whether these same brain boosting effects can also work for perfectly healthy adults. New research published in PLOS now indicates that it can.
Researchers at the University of Pittsburgh have determined that healthy young adults can improve their working memory by supplementing their diets with 2 grams of Omega-3 fatty acids per day.
To reach this conclusion, Rajesh Narendarn and his colleagues recruited 11 volunteers from various ethnicities ranging in age from 18 to 25 (the researchers conceded that this was a small sample size; this was a proof of concept study that will likely be expanded in future). After the participants were screened for any underlying health conditions, they underwent PET scans and had their blood samples analyzed. They were also asked to perform the n-back test (also called dual N-back training) — a standard (but challenging) working memory test in which participants are shown a series of letters and numbers. Working memory is assessed by asking the participants to recall the numbers that they're seeing one, two, and three times prior.
Interestingly, before the experiment even got started, the blood work showed that the volunteers were already experiencing the benefits of Omega-3s (as measured by plasma Omega-3) that they were getting as a normal part of their diets.
Once all these preliminary tests were done, the volunteers were given an Omega-3 supplementation regimen that lasted six months (n-3 PUFA Lovaza at 2 g/day). They were monitored monthly through phone calls and standard outpatient procedures.
After the six month period, the tests were re-administered, including the n-back test. The participants performed markedly better — most particularly on the 3-back phase of the test (what is the most challenging part). Based on this and subsequent blood tests and PET scans, the scientists concluded that the Omega-3 supplementation resulted in pro-cognitive effects. And they believe that it's the increased levels of DHA that's responsible.
This graph shows the relationship between pre-supplementation RBC DHA or EPA in x-axis and pre-supplementation performance (AHR) in 3-back test in y-axis. The AHR ranges from 1 (best performance) to −1 (worst performance), with a score of 0 corresponding to performance at chance level. RBC DHA (Panel A), but not EPA (Panel B) was associated with performance in the task.
One of the going theories to explain this effect is on account of enhanced dopamine storage and release. It's also possible that the Omega-3s are facilitating pro-cognitive effects on inflammation, cellular signaling and neural trafficking.
As noted, future studies will increase sample size, and also take into account the possibility that the participants performed better on the n-back tests because they had prior practice. In addition, Narendarn and his colleagues are hoping to better investigate the role of Omega-3s on dopamine release mechanisms, as well as the role played by prefrontal cortical dopamine function — what has been linked to working memory and cognitive performance.
The entire study can be found at PLOS.
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