Diet lacking in omega-3 fatty acids—nutrients found in fish—may weaken memory and also accelerate brain ageing, says a new study. ‘People with lower blood levels of omega-3 fatty acids had lower brain volumes that were equivalent to about two years of structural brain ageing,’ said study author Zaldy S. Tan, geriatrics researcher at the University of California, Los Angeles. Some 1,575 people with an average age of 67-years and free of dementia, underwent MRI brain scans. They were also given tests to measure mental function, body mass and the omega-3 fatty acid levels in their red blood cells, the journal Neurology reports. Researchers found that people whose DHA (docosahexaenoic acid, an omega-3 fatty acids compound) levels were among the bottom 25 percent of the participants had lower brain volume compared to people who had higher DHA levels, according to a California statement. Similarly, participants with levels of all omega-3 fatty acids in the bottom 25 percent also scored lower on tests of visual memory and executive function, such as problem solving and multi-tasking and abstract thinking.