Exposure to common food additive carrageenan leads to reduced sulfatase activity and increase in sulfated glycosaminoglycans in human epithelial cells Check out this book: Excitotoxins: The Taste That Kills
Some good books to read concerning nutrition are: The Magnesium Miracle by Carolyn Dean, Excitotoxins: The Taste That Kills by Russell L. Blaylock, and Health and Nutrition Secrets by Russell L. Blaylock.