Brain health is a complicated subject. There are many factors when it comes to keeping your brain healthy. Recent research performed at the Mayo Clinic has indicated that a higher fat, lower carbohydrate diet could be more beneficial to your brain and lower your risk of mental impairment.
According to Dr. David Perlmutter, "[Healthy dietary fat is] good for the heart, brain, immune system and just about every aspect of human physiology you consider."
Make sure your children's meals have some healthy fat component to them to increase their brain health. Some good options are olive, avocado, and coconut oil, wild-caught salmon (or other wild-caught small fish), 100% grass-fed beef, nuts and seeds, and pasture-raised eggs.
Source: http://www.drperlmutter.com/dietary-fat-brain/
https://www.drperlmutter.com/two-fundamentals-brain-healthy-diet/