A fish-heavy diet may help to prevent neurodegenerative conditions in later life.
Over the decades, a serious amount of research has gone into investigating whether eating more fish could help to reduce the risk of dementia and improve cognitive health. To date, the evidence supporting this theory is strong.
Omega fatty acids were initially considered to be the chemicals behind fish's neuroprotective powers, but studies backing this theory up have not been forthcoming.
Although plenty of marketing companies earnestly inform us that omega supplements will prevent dementia and keep our minds nimble for longer, the science does not back this claim up.
So, what component of fish does benefit our brains? According to the latest study to address this question, it might be a protein called parvalbumin.
A calcium-binding protein, parvalbumin is found in large quantities in many types of fish, particularly in muscle tissue. It is the most common trigger of allergic reactions in those who have fish allergies; parvalbumin is able to fire up the immune system by avoiding our digestive juices and passing into the blood.
From fish to Parkinson's
Although the exact mechanisms that drive Parkinson's disease are still being unraveled, a particular protein formation is known to be important. Alpha-synuclein, sometimes called the Parkinson's protein, is found in clumps in the brains of people with Parkinson's disease.
When proteins fold incorrectly, they tend to stick together, forming fibrils, or amyloids. Amyloids are not always unhealthy, but they are present in a number of neurodegenerative conditions, including Huntington's, Parkinson's, and Alzheimer's.
Recently, researchers from Chalmers University of Technology in Gothenburg, Sweden, ran tests to investigate how parvalbumin interacts with alpha-synuclein. Their findings are published this week in the journal Science Reports.
They revealed that parvalbumin "scavenges" alpha-synuclein, binding it up so that it can't form the disruptive clumps seen in Parkinson's. Lead study author Prof. Pernilla Wittung-Stafshede, head of the Chemical Biology Division at the university, explains:
"Parvalbumin collects up the 'Parkinson's protein' and actually prevents it from aggregating, simply by aggregating itself first."
In this way, parvalbumin has the potential to clean up abnormal amyloids before they get a chance to form. So, it is possible that eating fish with high levels of these proteins could have a protective effect.
Among many others, fish such as herring, cod, redfish, carp, red snapper, and sockeye salmon harbor high quantities of parvalbumin. However, levels fluctuate throughout the year.
"Fish is normally a lot more nutritious at the end of the summer, because of increased metabolic activity. Levels of parvalbumin are much higher in fish after they have had a lot of sun, so it could be worthwhile increasing consumption during autumn."
Nathalie Scheers, assistant professor, Chalmers University of Technology
A much-needed discovery
Because this type of aggregated protein is common in a number of neurodegenerative conditions, the researchers are keen to investigate the activity of parvalbumin further.
The excitement surrounding these findings is two-fold: firstly, they have identified another molecule that might help to fight neurodegenerative conditions; and, secondly, they have uncovered a new mechanism of action for drug designers to target.
Prof. Wittung-Stafshede explains the importance of this research and projects similar to it:
"These diseases come with age, and people are living longer and longer. There's going to be an explosion of these diseases in the future — and the scary part is that we currently have no cures. So we need to follow up on anything that looks promising."
Researchers from the same university are already planning follow-up investigations. Specifically, they plan to study how parvalbumin from herring is transported into human tissues.
Although this line of investigation is in its infancy, it makes exciting reading.