Eating Fish Reduces Alzheimer's Risk

Eating baked or broiled fish once a week improves your brain health and cuts your risk of developing mild cognitive impairment (MCI) and Alzheimer's disease, according to a new study from researchers at the University of Pittsburgh Medical Center and the University of Pittsburgh School of Medicine.

"This is the first study to establish a direct relationship between fish consumption, brain structure, and Alzheimer's risk," Dr. Cyrus Raji said in a statement. "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. In mild cognitive impairment, memory loss is present but to a lesser extent than in Alzheimer's disease. People with MCI often go on to develop Alzheimer's disease.

The study selected 260 cognitively normal individuals from the Cardiovascular Health Study, and information on fish consumption was gathered using the National Cancer Institute Food Frequency Questionnaire. Of the 163 patients who consumed fish on a weekly basis, 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 compare the amount of gray matter at the beginning of the study to the amount 10 years later.

The scientists then looked to see if the volume of gray matter was associated with fish consumption and a reduced risk of Alzheimer's disease. (When the amount of gray matter shrinks, it means that brain cells are also shrinking.) The study controlled for the presence or absence of apolipoprotein E4 (ApoE4), a gene that increases the risk of developing Alzheimer's, as well as for gender, age, education, obesity, physical activity, and race.

The researchers found that consumption of baked or broiled fish on a weekly basis was positively associated with the volume of gray matter in several areas of the brain by almost fivefold.

"Consuming baked or broiled fish promotes stronger neurons in the brain's gray matter by making them larger and healthier," Dr. Raji said. "This simple lifestyle choice increases the brain's resistance to Alzheimer's disease and lowers risk for the disorder."

The study also found increased levels of cognition in people who ate broiled or baked 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," Dr. Raji said. "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."

On the other hand, eating fried fish didn't appear to increase brain volume or protect against cognitive decline.

An earlier study from Louisiana State University found that eating fish helps protect the brain from problems associated with Alzheimer's disease, and a study from Australia's Aberdeen University found that fish oil slows the aging process while helping the brain to work faster. Many experts suggest eating two portions of fish each week or taking a 1,000 mg supplement three times a day.

Which fish give the best protection? The omega-3 fatty oils found in cold-water fish contain fatty acids essential for a healthy brain. A Dutch study found that older people with the highest blood levels of omega-3 oils scored much higher in cognitive tests. Cold-water fish include salmon, sardines, herring, and mackerel.