| Description | Endogenous sulfite is generated as a consequence of the body's normal processing of sulfur-containing amino acids. Sulfites occur as a consequence of fermentation and also occur naturally in a number of foods and beverages. As food additives, sulfiting agents were first used in 1664 and approved in the United States as long ago as the 1800s. Sulfite sensitivity occurs most often in asthmatic adults--predominantly women; it is uncommonly reported in preschool children. Adverse reactions to sulfites in nonasthmatics are extremely rare. Asthmatics who are steroid-dependent or who have a higher degree of airway hyperreactivity may be at greater risk of experiencing a reaction to sulfite-containing foods. Sulfite sensitivity reactions vary widely, ranging from no reaction to severe. The majority of reactions are mild. These manifestations may include dermatologic, respiratory, or gastrointestinal signs and symptoms. The precise mechanisms of the sensitivity responses have not been completely elucidated. Inhalation of sulfur dioxide (SO2) generated in the stomach following ingestion of sulfite-containing foods or beverages, a deficiency in a mitochondrial enzyme, and an IgE-mediated immune response have all been implicated. Exogenously supplied sulfite is detoxified by the enzyme sulfite oxidase. Sulfite oxidase (EC 1.8.3.1) is 1 of 3 enzymes in humans that requires molybdenum as a cofactor. Sulfite oxidase deficiency is a rare autosomal inherited disease with severe neurological symptoms such as untreatable seizures, attenuated growth of the brain and mental retardation. It results from defects in the enzyme sulfite oxidase, which is responsible for the oxidation of sulfite to sulfate. This reaction is the final step in the degradation of sulfur containing metabolites including the amino acids cysteine and methionine. is a neurometabolic disease that results in severe developmental delay and premature death. The term isolated sulfite oxidase deficiency is used to define the deficiency caused by mutations in the sulfite oxidase gene. This differentiates it from another version of sulfite oxidase deficiency that is due to defects in the Moco biosynthetic pathway. Isolated sulfite oxidase deficiency is a rare but devastating neurologic disease that usually presents in early infancy with seizures and alterations in muscle tone. (PMID: 16234925 , 16140720 , 8586770 ) [HMDB]. Sulfite is found in many foods, some of which are sunflower, grapefruit/pummelo hybrid, passion fruit, and kelp. |
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