Eating fish once a week is good for brain health, as well as lowering your risk of developing Alzheimer's disease and MCI (Mild Cognitive Impairment), researchers from the University of Pittsburgh School of Medicine explained at the annual meeting of RSNA (Radiological Society of North America), Chicago, yesterday.
Cyrus Raji, M.D., Ph.D. said:
"This is the first study to establish a direct relationship between fish consumption, brain structure and Alzheimer's risk. 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."
To broil means to cook by direct radiant heat, as one would under an electric element or over a grill.
To bake (in this text) means to cook with dry heat, e.g. to oven cook.
It is estimated that about 5.1 million people in the USA have Alzheimer's disease, says the National Institute on Aging. Mild cognitive impairment is sometimes the first step towards Alzheimer's.
Raji and team carried out a study on 260 cognitively healthy people from the Cardiovascular Health Study. They were given a questionnaire (National Cancer Institute Food Frequency Questionnaire) which included details on their fish consumption.
163 of the participants ate fish at least once a week, many of whom did so up to four times weekly. They all underwent a 3-D volumetric MRI brain scan. A brain mapping technique, called Voxel-based morphometry, was utilized to determine whether there might be a link between fish consumption at the start of the study and the structure of their brains a decade later.
The researchers gathered and analyzed data to find out whether the preservation of brain volume linked to eating fish might have an impact on Alzheimer's disease risk (reducing the risk). They took into account several factors which may have influenced the results, including participants' race, education, sex, age, levels of physical activity, as well as the presence of a gene that raises Alzheimer's risk (ApoE4, or apolipoprotein E4).
Brain health is closely linked to brain volume, the more brain volume you can preserve as you age, the better your long-term brain health. If the amount of gray matter starts to go down, it means the brain cells are shrinking.
The researchers found that those who ate baked or broiled fish at least once a week tended to have better preservation of volume in several brain areas, including the orbital frontal cortex, posterior cingulate cortex, and hippocampus. Greater volume in these brain areas was found to be associated with a five-times lower risk of developing Alzheimer's or MCI.
Dr. Raji said:
"Consuming baked or broiled fish promotes stronger neurons in the brain's gray matter by making them larger and healthier. This simple lifestyle choice increases the brain's resistance to Alzheimer's disease and lowers risk for the disorder."
The investigators also noticed that those who ate fish regularly had higher levels of cognition, compared to the participants who rarely ate fish.
Dr. Raji said:
"Working memory, which allows people to focus on tasks and commit information to short-term memory, is one of the most important cognitive domains. 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."
Raji emphasized that according to his findings, dried or fried fish do not seem help preserve brain volume or lower Alzheimer's risk - the fish has to be baked or broiled.
Written by Christian Nordqvist