Phospholipids and Cholesterol are good for many things including healthy gut. Eggs are a good source for both. Lecithin is a great idea too.
The structure of biological membranes typically includes several types of molecules in addition to the phospholipids comprising the bilayer. A particularly important example in animal cells is cholesterol, which helps strengthen the bilayer and decrease its permeability. Cholesterol also helps regulate the activity of certain integral membrane proteins.