“This is the first study to establish a direct relationship between fish consumption, brain structure and Alzheimer’s risk,” said Cyrus Raji, M.D., Ph.D., from UPMC and the University of Pittsburgh School of Medicine. “The results showed that people who consumed baked or broiled fish at least one time per week had better preservation of gray matter volume on MRI in brain areas at risk for Alzheimer’s disease.”
Alzheimer’s disease is an incurable, progressive brain disease that slowly destroys memory and cognitive skills. According to the National Institute on Aging, as many as 5.1 million Americans may have Alzheimer’s disease. People with MCI often go on to develop Alzheimer’s.
For the study, the researchers selected 260 cognitively normal individuals from the Cardiovascular Health Study. Information on fish consumption was gathered using the National Cancer Institute Food Frequency Questionnaire. There were 163 patients who consumed fish on a weekly basis and the majority ate fish one to four times per week. Each patient underwent 3-D volumetric MRI of the brain. Voxel-based morphometry, a brain mapping technique that measures gray matter volume, was used to model the relationship between weekly fish consumption at baseline and brain structure 10 years later. The data were then analyzed to determine if gray matter volume preservation associated with fish consumption reduced risk for Alzheimer’s disease. The study controlled for age, gender, education, race, obesity, physical activity, and the presence or absence of apolipoprotein E4 (ApoE4), a gene that increases the risk of developing Alzheimer’s.
Brain volume is crucial to brain health. When it remains higher, brain health is being maintained. Decreases in gray matter indicate that brain cells are shrinking.
The findings show that consumption of baked or broiled fish on a weekly basis was positively associated with gray matter volumes in several areas of the brain. Greater hippocampal, posterior cingulate and orbital frontal cortex volumes in relation to fish consumption reduced the risk for five-year decline to Alzheimer’s or MCI by five-fold. MCI is thought to be a precursor form of Alzheimer’s in which memory loss is present but to a lesser extent.
“Consuming baked or broiled fish promotes stronger neurons in the brain’s gray matter by making them larger and healthier,” noted Dr. Raji. “This simple lifestyle choice increases the brain’s resistance to Alzheimer’s disease and lowers risk for the disorder.”
The results also demonstrated increased levels of cognition in people who ate fish.
“Working memory, which allows people to focus on tasks and commit information to short-term memory, is one of the most important cognitive domains,” added Dr. Raji. “Working memory is destroyed by Alzheimer’s disease. We found higher levels of working memory in people who ate baked or broiled fish on a weekly basis, even when accounting for other factors, such as education, age, gender and physical activity.”
The researchers noted that eating fried fish however, did not increase gray matter volume or protect against cognitive decline.
Funding for the study was provided by the National Institute on Aging. Co-authors include Kirk Erickson, Ph.D., Oscar Lopez, M.D., Lewis Kuller, M.D., Ph.D., and James Becker, Ph.D., all from the University of Pittsburgh; Mario Riverol, M.D., from the University of Navarra, Pamplona, Spain; Paul Thompson, Ph.D., from the University of California Los Angeles; and H. Michael Gach, Ph.D., from the Nevada Cancer Institute.