[A version of this item appears in: Dementia: the Latest Evidence Newsletter (RWHT), Volume 2 Issue 6, January 2012].
Dietary habits could have a role in reducing the risk for cognitive decline and dementia, according to a cohort study of 260 people over 10 years. The Daily Telegraph reported that “Fish could protect against Alzheimer’s” on the basis of findings which indicate that people eating baked or grilled fish once a week are up to five times less likely to suffer from mental deterioration.
Researchers have discovered this association between the amount of fish eaten and the size of certain brain structures over 10 years (as measured by brain-imaging) and the risk of loss of brain function (cognitive decline) over five years.
Eating baked or grilled fish at least once a week was associated with larger grey matter volume 10 years later in certain brain structures involved in memory and learning; i.e. the hippocampus, precuneus, posterior cingulate and orbital frontal cortex.
There was no similar association between consumption of fried fish and grey matter volume or cognitive decline.
Note: This research does not report on Alzheimer’s Disease specifically, but rather on cognitive decline generally. Cognitive decline is often a precursor to Alzheimer’s Disease.
Note: Previous research has not shown any association between the fatty acids found in oily fish and a reduced future risk of dementia.
This NHS Choices critical appraisal points out the potential weaknesses of the study design and concludes it is not possible to draw firm conclusion until further information becomes available.
Can eating fish prevent Alzheimer’s? London: NHS Choices, November 30th 2011.
Eating fish reduces your risk of developing cognitive decline. London: Alzheimer’s Society (web page), November 30th 2011.