Summary: People who consumed fish as a regular part of their diet had a lower risk of vascular brain disease, a condition that can lead to stroke or dementia.
Source: Alzheimer’s Research UK
Researchers in France have found a link between eating more fish and a lower risk of vascular brain disease. Vascular brain disease involves damage to blood vessels in the brain and is a risk factor for vascular dementia and stroke.
The research is published today in the journal Neurology.
Researchers from the University of Bordeaux, analyzed data from the Three City Study, a large study of the relationship between vascular diseases and dementia.
The researchers analyzed MRI scans from 1,623 people over the age of 65 with no medical history of stroke, cardiovascular disease or dementia. The participants also filled in a questionnaire about their dietary habits.
The participants were split into four groups, according to how frequently they ate fish: less than once week, about once a week, two to three times a week, or four or more times a week. The researchers compared the number of signs of blood vessel disease between people in each group.
Participants who said that they ate more fish had fewer signs of damage in MRI scans of their brains than those who ate it less frequently.
The association between fish intake and blood vessel disease was stronger in people aged 65–69 compared to older people in the study, and there was no significant relationship between in people over 75 years old.
Dr. Rosa Sancho, head of research at Alzheimer’s Research UK, said: “For most of us our risk of dementia depends on the complex interaction of multiple genetic and environmental factors. Understanding which aspects of our lifestyle have the greatest effect on our brain health is key to empowering people to make informed decisions about how they live their lives.
“Observational studies like this are not able to pinpoint cause and effect. While the researchers attempted to control for other factors that could underlie differences in signs of vascular brain disease, it is difficult to definitively attribute these to the amount of fish in people’s diets. As participants had a single brain scan and reported their dietary habits at one point in time, it’s not clear how relevant the findings are to long-term brain health.
“The NHS recommends eating two portions of fish a week as part of a balanced diet. We know that oily fish can be a source of important fatty acids, but it is unlikely that any specific food or supplement holds the key to maintaining a healthy brain.
“Research suggests that what is good for your heart tends to be good for the brain and taking steps to control blood pressure and cholesterol, not smoking, only drinking within recommended limits and leading an active lifestyle have all been linked to better brain health as we age.”
Fish Intake and MRI Burden of Cerebrovascular Disease in Older Adults
Background and Objective:
Fish intake may prevent cerebrovascular disease (CVD), yet the mechanisms are unclear, especially regarding its impact on subclinical damage. Assuming that fish may have pleiotropic effect on cerebrovascular health, we investigated the association of fish intake with global CVD burden based on brain MRI markers.
This cross-sectional analysis included participants from the Three-City Dijon population-based cohort (aged ≥65 years) without dementia, stroke, or history of hospitalized cardiovascular disease, who underwent brain MRI with automated assessment of white matter hyperintensities, visual detection of covert infarcts, and grading of dilated perivascular spaces. Fish intake was assessed through a frequency questionnaire and the primary outcome measure was defined as the first component of a factor analysis of mixed data applied to MRI markers. The association of fish intake with the CVD burden indicator was studied using linear regressions.
In total, 1,623 participants (mean age, 72.3 years; 63% women) were included. The first component of factor analysis (32.4% of explained variance) was associated with higher levels of all three MRI markers. Higher fish intake was associated with lower CVD burden. In a model adjusted for total intracranial volume, compared to participants consuming fish <1 per week, those consuming fish 2-3 and ≥4 times per week had a β = -0.19 (95% CI, -0.37; -0.01) and β = -0.30 (-0.57; -0.03) lower indicator of CVD burden, respectively (P trend <0.001).
We found evidence of effect modification by age, so that the association of fish to CVD was stronger in younger participants (65-69 years) and not significant in participants aged ≥75 years. For comparison, in the younger age group, consuming fish 2-3 times a week was roughly equivalent (in opposite direction) to the effect of hypertension.
In this large population-based study, higher frequency of fish intake was associated with lower CVD burden, especially among participants younger than 75 years, suggesting a beneficial effect on brain vascular health before manifestation of overt brain disease.
Classification of Evidence:
This study provides Class II evidence that in individuals without stroke or dementia, higher fish intake is associated with lower subclinical CVD at MRI.