SULFUR – THE FORGOTTEN NUTRIENT
Sulfur is an inorganic element and forms part of several molecules in the body, including amino acids, proteins, enzymes, vitamins, and more.1 Following calcium and phosphorus, sulfur is the third most abundant mineral in the human body, representing ~0.3% of total body mass.2 Dietary sulfur comes from protein where 2 of the 20 amino acids, methionine, and cysteine, contain sulfur (the sulfur-containing amino acids; SAAs). The amount of SAAs in protein varies according to the source, e.g., dairy is 4% SAAs and egg whites 8% SAAs.3 Additionally, glutathione (a natural intracellular antioxidant) provides a source of dietary sulfur and is found in fruits and vegetables.4 Currently, there is no recommended dietary allowance (RDA) for sulfur. There is, however, a recommended daily intake for the sulfur-containing amino acids. The estimated requirement for methionine (combined with cysteine) was determined in 1989 to be 14 mg/day per kg body weight in adults.