Fish, Vascular Lesions, and Dementia Risk

If preventing heart disease isn’t enough motivation to eat more fish, perhaps reducing risks for dementia will get more fish onto plates.A recent study found that moderate consumption of fish may help prevent the vascular disease that may lead to dementia. Lead study author Aline Thomas, a doctoral student with the Bordeaux Population Health Research Center at Bordeaux University in France notes, "Previous studies, including work from our team in France and others in the U.S., reported protective associations of eating fish against cognitive decline and risk of dementia in later life."This latest study discovered that, among healthy adults aged 65 and up, "two or more servings of fish per week may protect the brain against vascular lesions, before obvious signs of dementia appear."One caveat was noted: the protective impact was only observed in seniors under the age of 75. Her study was published in a recent issue of Neurology wherein she and colleagues documented the results of brain scans in over 1,600 men and women over 65 with an average age of 73. None of the study subjects had a previous history of dementia, stroke, or heart disease.Three obvious signs of vascular disease were evaluated. Scans showed that small brain lesions were observed in 2% of subjects, brain cavities were seen in 8%, and fluid build up in brain tissue was seen in 6%.These three signs can occur prior to obvious symptoms of dementia. All have been associated with a long-term higher risk of dementia and overall decline in mental sharpness.During the study, subjects were asked about their food habits and how much fish -- including salmon, tuna and/or sardines -- were eaten weekly.On average, participants ate fish about twice per week.The scientists then compared the development of brain lesions, cavities, and fluid build up with the subjects’ fish consumption habits.Results showed that vascular disease, which can impact blood flow to the brain, was seen in only 18% of those who consumed fish four times per week and 23% in subjects under 75 that ate fish three times per week.Nearly a third of non-fish eaters developed key markers for vascular disease. The researchers noted that their results show an association and don’t prove that eating fish will prevent the onset of dementia. But why was no link seen in those 75 and older? "The reasons for this specificity are not clear yet," said Thomas. "One hypothesis is that fish consumption might be more beneficial at the earliest stages of the disease process, thus among younger participants."If these results continue with further research, the findings may offer a simple and inexpensive way to help seniors reduce their risk of dementia.Lona Sandon, program director of clinical nutrition in the school of health professions at UT Southwestern Medical Center in Dallas notes that these results are not a surprise."The brain requires omega-3 fats found in salmon and sardines to develop and stay healthy throughout life," Sandon explained, highlighting the fact that brain tissue is made up of these healthy fats. "Omega-3s are just as important for brain health and promoting clear vessels in the brain as they are for heart health."Sandon notes that the brain’s need for healthy fats begins in infancy for normal growth and development. Healthy fats are not just for seniors.She advises people to start eating fatty fish and other foods containing omega-3s  --including walnuts and flax seeds -- now.Need some easy ways to get more fish or omega-3s in your diet? Try these:

• Make salmon salad using canned salmon and light mayo.
• Purchase frozen salmon to use all-year round.
• Add canned tuna to tossed salad.
• Toss ground flaxseed into oatmeal, smoothies or yogurt.
• Snack on walnuts and fresh fruit. 
• Enjoy fish twice per week per AHA recommendations.
• Try chia seed pudding with blueberries for a sweet treat.

By Lisa Andrews, MEd, RD, LDReference:Aline Thomas, PhD student, Inserm U1219, Bordeaux Population Health Research Center, Bordeaux University, France; Lona Sandon, PhD, RDN, LD, program director and associate professor, department of clinical nutrition, school of health professions, UT Southwestern Medical Center, Dallas; Neurology, Nov. 3, 2021