Some people have an impaired ability to oxidize and detoxify sulfur compounds.
A buildup in the body of excess sulfur compounds can be uncomfortable and even life threatening. Two forms of this impairment have been observed. One results in an inability to regulate the amino acid cysteine, and is indicated by an increase of cysteine levels in blood plasma, and other tissues samples along with discomfort in eating foods rich in sulfur amino acids. The second impairment produces an inefficiency in converting sulfur dioxide and sulfides into non-toxic sulfate. Paradoxically, and quite frustratingly, persons chronically ill can also have impaired glutathione synthesis and depletion of body stores of glutathione.