Fish and other foods rich in a type of beneficial fat may help prevent Alzheimer's disease, says a study out Tuesday.
The new finding fits in with a growing body of scientific evidence that suggests Americans could reduce their risk of developing all sorts of killer diseases, such as heart disease, cancer and now Alzheimer's, if they ate a healthier diet - one rich in fish, fruits and vegetables.
Everyone would benefit by adopting that diet, but boomers and younger people might gain a bigger health edge from eating more brain food. Researchers believe that Alzheimer's takes years to develop. About 4 million Americans now suffer from the incurable disease, and that number is expected to grow to 14 million by the end of this century, according to the Alzheimer's Association.
Martha Clare Morris of Rush-Presbyterian-St. Luke's Medical Center in Chicago and her colleagues recruited 815 people between the ages of 65 and 94. At the start of the study, recruits showed no sign of Alzheimer's disease, which causes memory loss, confusion and the inability to perform routine daily tasks.
The researchers asked about their diet and kept track of the volunteers for an average of four years. At the end, 131 people developed Alzheimer's.
A statistical analysis in Tuesday's Archives of Neurology revealed that people who ate fish once a week or more had a 60% lower risk of Alzheimer's disease than those who rarely or never ate fish. Oily fish such as salmon contain omega-3 fatty acids that already have been shown to reduce the risk of dying from heart disease. Other foods, such as nuts and oil-based salad dressing, also contain these helpful fats, Morris says.
Animal research suggests these omega-3 fatty acids help nerve cells fire more efficiently and thus might help boost memory abilities, she says. Or it may be that people who eat more fish also choose to eat more fruits and veggies. Other studies suggest that fruits and vegetables may stave off Alzheimer's because they contain antioxidants that protect brain cells, says Robert Friedland, a neurologist at Case Western Reserve University in Cleveland.
The Chicago study, the first human study in the USA, supports previous findings from two European studies.
The link between fish and a lower risk of Alzheimer's must be confirmed with additional research, says Bill Thies of the Alzheimer's Association. But consumers don't necessarily need to wait for a final verdict from science. "There are lots of good reasons to eat more fish," Thies says.
Many health experts agree, but they also warn that people, particularly pregnant women and young children, should avoid fish high in methylmercury, a harmful contaminant found in some fish. Swordfish, shark, tuna and other large predatory fish can contain lots of mercury, while salmon, flounder and cod generally don't have as much.
Fish oil supplements, which were not considered in Tuesday's study, also can be a good source of omega-3 fatty acids, Friedland says.
Source: USA Today