While DHA is essential for the proper development of the infant brain, it also plays a vital role in the ongoing structure and function of the adult brain. It is a component of several important phospholipids in the brain, with the highest levels of DHA being found in phosphatidylethanolamine (PE) and phosphatidyl-serine (PS). Lower levels exist in phosphatidyl-cholines (PC). Structurally, DHA comprises 22 carbons and six double bonds, making it the most unsaturated fatty acid in cell membranes and an important ingredient in increasing the fluidity of cell membranes.