The body contains about 60% water and about 20% fat. Oil and water doesn't mix and so how does the body transport fats (lipids) in the blood (50% water) and into the brain (80% water) kidney and muscles (75%). Dietary fat is made up of fatty acids, which are classified according to how many carbons make up their chain length. DHA is the longest of the omega-3 fatty acids (22 carbons) and is particularly important for brain development because it is present in higher concentrations in nerve cell membranes. So, back to our question. How do we transport fat through the blood and into the brain and other tissues when there is so much water around. The answer lies in a molecule called a 'phospholipid' that carries one or two fatty acid chains, each attached to a carbon 'hook' of a set of 3 carbons (glycerol) that are attached (through phosphate) to a very water soluble molecule like choline. A 'phospho - lipid' with choline is called 'Phosphatidyl Choline' (or PC) and this makes the molecule fat (or oil) soluble on the fatty acid side and water soluble on the choline side. This is an ingenious way to solve the oil-water paradox and in fact is the very basis upon which these phospholipids are pressed into service as the building blocks of membranes - the structure that contains all the fluid and structures of the cell.