As a Harvard team wrote, concerning the outcomes of a rat study, “… increased brain [levels of] DHA significantly enhances hippocampal neurogenesis [growth of brain cells and inter-cell connections].” (He C 2009)
But unfortunately, as was noted in a 2010 evidence review, “… hippocampal DHA levels decrease with age and in the brain disorder Alzheimer's disease, and this decrease is associated with reduced hippocampal-dependent spatial learning memory ability.” (Su HM 2010)
In other words, gradual decline in brain levels of DHA may explain why it becomes harder to remember where you put your keys or parked you car!
While it's long been clear that DHA is critical to fundamental memory functions, the full range of DHA's roles in memory support remains to be explored.
Now, researchers at the University of Alberta, Canada, may have found one more reason why DHA appears so important to achieving and maintaining optimal memory performance (Connor S et al. 2012).
Canadian study sees DHA enhancing memory center's internal communications
According to Professor Yves Sauvé, Ph.D., “We wanted to find out how fish intake improves memory.” (UA 2012)
First, his team confirmed that lab rats fed a high-DHA diet had 29 percent more DHA in the hippocampus – a section of the brain key to memory formation – when compared to animals fed regular rat chow.
Other researchers have already observed this effect. So, as he explained, another finding represents the real breakthrough.
To clarify things, they supplemented mice with a DHA-enriched diet to see whether that would alter the ability of synapses to undergo activity-dependent changes in the hippocampus (Connor S et al. 2012).
And to allow for quick, clear outcomes, they tested the animals' ability to form new spatial memories.
“What we discovered is that memory cells in the hippocampus could communicate better with each other and better relay messages when DHA levels in that region of the brain were higher,” said Suave. (UA 2012)
He went on to make the obvious point: “This could explain why memory improves on a high-DHA diet.” (UA 2012)
Supplementing your diet with DHA, such as increasing fish intake or taking supplements, could prevent declining DHA levels in the brain as we age, says Sauvé.
Most fish and fish oils contain more omega-3 EPA than omega-3 DHA, but provide more than enough DHA to sharply boost blood and brain levels within a few weeks.
And many infant formulas are now fortified with omega-3 DHA.
This research was made possible by a grant from Alberta Innovates Health Solutions, a publicly funded research foundation.
Earlier this year, Sauvé and his colleagues discovered that supplemental DHA prevents the accumulation of a toxic molecule at the back of the eye that causes age-related vision loss. (See “New Eye Benefit Seen in Omega-3s”.)
Cao D, Kevala K, Kim J, Moon HS, Jun SB, Lovinger D, Kim HY. Docosahexaenoic acid promotes hippocampal neuronal development and synaptic function. J Neurochem. 2009 Oct;111(2):510-21. Epub 2009 Aug 13.
Chung WL, Chen JJ, Su HM. Fish oil supplementation of control and (n-3) fatty acid-deficient male rats enhances reference and working memory performance and increases brain regional docosahexaenoic acid levels. J Nutr. 2008 Jun;138(6):1165-71.
Connor S, Tenorio G, Clandinin MT, Sauvé Y. DHA supplementation enhances high-frequency, stimulation-induced synaptic transmission in mouse hippocampus. Appl Physiol Nutr Metab. 2012 Jun 20. [Epub ahead of print]. Accessed at http://www.nrcresearchpress.com/doi/pdf/10.1139/h2012-062
He C, Qu X, Cui L, Wang J, Kang JX. Improved spatial learning performance of fat-1 mice is associated with enhanced neurogenesis and neuritogenesis by docosahexaenoic acid. Proc Natl Acad Sci U S A. 2009 Jul 7;106(27):11370-5. Epub 2009 Jun 22.
Su HM. Mechanisms of n-3 fatty acid-mediated development and maintenance of learning memory performance. J Nutr Biochem. 2010 May;21(5):364-73. Epub 2010 Mar 16. Review.
University of Alberta (UA). Medical researchers discover a potential explanation for why a diet high in DHA can improve memory. June 28, 2012. Accessed at http://www.med.ualberta.ca/Home/NewsEvents/News/article.cfm?ID=2431