Eggs are brain food. That's largely because of an essential nutrient called choline. It's a component of cell membranes and is required to synthesize acetylcholine: a neurotransmitter. Studies show that a lack of choline has been linked to neurological disorders and decreased cognitive function. Shockingly, more than 90% of Americans eat less than the daily recommended amount of choline, according to a U.S. dietary survey.