Phospholipids (PLs) consist of fatty acids and a phosphate-containing moiety attached to either glycerol or (the amino alcohol) sphingosine, thus resulting in compounds with fat — soluble and water-soluble regions that are ubiquitors in cell membranes. Glycerol-containing PLs include phosphatidic acid, phosphatidylcholine (PC), phophatidylethanolamine (PE), phosphatidylinositol, and phosphatidylserine. Sphingomyelin (SPH), a major PL, consists of sphingosine and PC. Phospholipids and choline entail several benefits for human health, as depicted in Table 10.4. The level of phospholipids in various red macroalgae varies from 10-21% of total lipids; the main ones are PC (62-78%) and PG (10-23%) (Dembitsky and Rozentsvet, 1990).

Dietary phospholipids act as natural emulsifiers and as such they facilitate digestion and absorption of fatty acids, cholesterol, and other lipophilic nutrients. Algal phopholipids appear to bear a number of advantages relative to fish oils because they are more resistant to oxidation (rancidity), have higher contents of EPA and DHA and provide them with a better bioavailability, and entail a wider spectrum of health benefits for humans and animals (Holdt and Kraan, 2011).