Sulfur is the third most abundant mineral in your body, based on percentage of total body weight. Sulfur bonds are required for proteins to maintain their shape, and these bonds determine the biological activity of the proteins. In addition to bonding proteins, sulfur is also required for the proper structure and biological activity of enzymes. Sulfur also plays an important role in the body's electron transport system, as part of iron/sulfur proteins in mitochondria - the energy factories of the cells. It helps in Vitamin-B thiamine (B1) and biotin conversion, which in turn are essential for converting carbohydrates into energy, synthesizes important metabolic intermediates, such as glutathione and insures proper insulin function. The insulin molecule consists of two amino acid chains connected to each other by sulfur bridges, without which the insulin cannot perform its biological activity. It also has a detoxification role. Although there is no official RDA for sulfur, it is a critical nutrient. Daily intake is usually 800 to 900 milligrams of sulfur per day.