In a six-year study of more than 3,500 children ages 6 to 16, researchers discovered that those who consumed polyunsaturated fatty acids, such as omega-3s, were more likely to do better on the digit span test, a short-term memory test (Journal of Nutrition, 2005, vol. 135, no. 8). Each 5 percent increase in these good fats was associated with improved performance on the test. This study supports recent research that omega-3 fatty acids increase brain function in children. Good sources of polyunsaturated fats include salmon and other fish, green leafy vegetables, nuts, and seeds like flax and hempseed.