Eating fish helps keep the brain young, say scientists. Research found that those whose diet lacked an essential nutrient present in oily fish experienced faster brain shrinkage and mental decline. Scientists studied MRI brain scans and levels of docosahexaenoic acid (DHA) — an omega-3 fatty acid — in the red blood cells of 1,576 people, with an average age of 67, who also took a test of mental function. The scans showed that the participants whose DHA levels were among the bottom 25 per cent had smaller brains. Dr Zaldy Tan, an Alzheimer\'s researcher from the University of California, Los Angeles, who led the research, said: \"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.\" Low levels of all omega-3 fatty acids were associated with poor test scores for visual memory, problem solving, multitasking and abstract thinking, the study, reported in the journal Neurology, found. The richest source of DHA is oily fish, such as herring, mackerel and sardines. From: Gulfnews