There is evidence to suggest that the protein β-parvalbumin found in fish inhibits the formation of α-synuclein (the protein present in Parkinson’s Disease). The cross-reaction of β-parvalbumin and human amyloidogenic proteins may explain at least some of the health benefits of fish consumption.
Werner, T. Kumar, R. [and] Horvath, I. [et al] (2018). Abundant fish protein inhibits α-synuclein amyloid formation. Scientific Reports. April 3rd 2018; 8(1): 5465.
Possibly also of interest, regarding foods which may help to prevent or delay dementia:
The foods that might help with dementia. London: BBC Health News, April 23rd 2018.
Possibly of further interest, four studies were presented at the Alzheimer’s Association International Conference 2017 (AAIC®2017):
You are what you eat? The role of diet in healthy brain ageing and dementia risk. [London. Online]: Alzheimer’s Research UK, July 17th 2017.
This relates to:
Healthy Eating Habits May Preserve Cognitive Function and Reduce the Risk of Dementia. Alzheimer’s Association International Conference® 2017. List of July 17th 2017 Press Releases. [London. Online]: Alzheimer’s Association, July 2017.