Which protein is primarily responsible for transporting fatty acids in the blood?

• A. Lipoprotein
• B. Retinol-binding protein
• C. Albumin
• D. Hemoglobin

Answer: (C)

Fatty acids in the bloodstream are hydrophobic, so they need a soluble carrier. The main carrier is albumin, a abundant plasma protein with multiple hydrophobic binding sites that can bind several fatty acid molecules. This binding keeps fatty acids soluble, buffers their free concentration, and lets them be transported from tissues where they’re released (like adipose tissue during lipolysis) to tissues that need them or to the liver for processing. Lipoproteins do carry lipids in the blood, including fatty acids as part of triglycerides within the particles, but they are not the primary carriers of circulating free fatty acids. Retinol-binding protein transports vitamin A, and hemoglobin carries oxygen.