Those with higher levels of omega-3 fatty acids, which are found in fish oil, appear to have larger brain volumes in old age, according to a new study in Neurology. Shrinking brain volume can be a sign of Alzheimer’s disease.

Investigators looked at levels of omega-3 fatty acids EPA+DHA in red blood cells in more than 1,000 women. Eight years later, when the women were an average age of 78, MRI scans were taken to measure their brain volume.

Those with higher levels of omega-3s had larger total brain volumes eight years later, researchers found.

“These higher levels of fatty acids can be achieved through diet and the use of supplements, and the results suggest that the effect on brain volume is the equivalent of delaying the normal loss of brain cells that comes with aging by one to two years,” said study author James V. Pottala, Ph.D., of the University of South Dakota in Sioux Falls and Health Diagnostic Laboratory Inc., in Richmond, VA.