The main differentiating factor between lectin and lecithin is that lectin is a secondary metabolite. Concanavalin A is a plant protein which binds with carbohydrate whereas lecithin is a fatty substance which is found in plant and animal tissues. Lectin, due to its ability to bind with carbohydrate reduces nutrient absorption. Lecithin itself is an essential fatty nutrient, a major component of phosphatidylcholine with the ability to lower the bad cholesterol in the body.