Findings may help explain why most population studies link fish-rich diets to reduced rates of dementia
by Craig Weatherby
“Fish is brain food” goes the saying... and there's clearly something to that old saw.
Diets rich in fish-borne omega-3 fats have long been linked to reduced rates of Alzheimer’s disease and other forms of dementia.
While the evidence is mixed and includes no large clinical trials, this association is supported by cell and animal studies that have detected beneficial effects that omega-3s exert on processes related to brain health.
For more information, including links to related news reports, see “Omega-3s Boost Aging Brains in Clinical Trial”.
Now, Australian scientists believe they’ve discovered one possible reason for omega-3s’ presumed protective powers.
Zinc may be one missing link in omega-3s’ brain health effects
Researchers at Melbourne’s Deakin University have found that DHA
—one of the two key omega-3s in fish fat
—regulates the levels of zinc in brain cells (Suphioglu C et al. 2010).
Lead researcher Margaret Ackland, Ph.D., leads a group that studies the function of trace metals in human health, and identifies “molecular transporters” that control the movement of zinc and copper into and out of cells.
Professor Ackland and her colleagues set out to study the relationship—if any—between omega-3 DHA and zinc in the neurons (nerve cells) responsible for transmitting signals in the brain.
As she told the Australian Associated Press, “We found that when the level of DHA in neuronal cells drops, the level of zinc rises. The higher levels of zinc can be toxic, resulting in cell death... a key feature of… Alzheimer’s” (Rose D 2010).
She went on to make a key observation: “We believe that having omega-3 fatty acids in the diet helps keep the levels of zinc in the brain in balance and helps prevent the increase in levels that triggers cell death” (Rose D 2010).
There’s no doubt that DHA is essential for healthy brain functioning, though any link to zinc was unknown until this new study demonstrated a strong one.
Professor Ackland noted the novelty of her team’s finding and its implications:
“To the best of our knowledge this is the first time a direct link has been demonstrated between the levels of DHA and zinc in the brain's neuronal cells. Our work provides insights into how fatty acid nutrition may prevent the development of Alzheimer’s...” (Rose D 2010).
She plans to conduct future studies designed to discover how the DHA controls zinc in the brain, so stay tuned.
- Rose D. Omega-3 protects brain from Alzheimer’s. February 2, 2010. Australian Associated Press (AAP). Accessed at http://news.smh.com.au/breaking-news-national/omega3-protects-brain-from-alzheimers-20100202-nabw.html
- Suphioglu C, De Mel D, Kumar L et al. The omega-3 fatty acid, DHA, decreases neuronal cell death in association with altered zinc transport. FEBS Letters; volume 584, issue 3, pages 612-618 (5 February 2010). Received 26 October 2009; received in revised form 4 December 2009; accepted 9 December 2009. published online 14 December 2009.