23 Jan 2014 --- People with higher levels of the omega-3 fatty acids found in fish oil may also have larger brain volumes in old age equivalent to preserving one to two years of brain health, according to a study published in the January 22, 2014, online issue of Neurology, the medical journal of the American Academy of Neurology. Shrinking brain volume is a sign of Alzheimer's disease as well as normal aging.