Egg yolks are one of nature's richest sources of choline, a B vitamin that is one of the most important nutrients for brain health. Choline is a building block of the valuable neurotransmitter acetylcholine, which is vital for memory, learning and thinking.

This vitamin is particularly important during pregnancy because it's essential for the brain development in the fetus. The choline in egg yolks helps maintain the flexibility of brain cell membranes, which is critical for the quick transmission of thoughts and impulses.