Question posted to Ask Alice! of Columbia University Dear Alice, My diet, which concentrates on fish, such as salmon, sea bass, etc., and shellfish, seems to have improved my HDL levels without increasing my LDL levels. Can you explain the relationship of high fish and shellfish diets on HDL/LDL levels in the bloodstream? --Curious Read more about this at Questions about Fish Oil. After reading please leave your comments and thoughts. Or contact me.