This test provides information about sulfur metabolism. In the test, total sulphate, free sulphate, sulphite, thiocyanate and thiosulphate are measured in the urine.
Sulfur (S) fulfills an important function in the body during detoxification. Among other things many drugs, the (neuro) toxic cyanide ion and endogenous and exogenous neurotransmitters, catecholamines, peptide hormones, steroids, bile acids, glucosaminoglycans, amines and phenols are detoxified via sulfation.
Good sulphation is also important for the function and integrity of the intestinal and renal membranes and for the function of various enzymes, including insulin, gastrin and cholecytokinin (CCK).
Most sulfur (sulphate) for sulphation comes from the oxidation of the sulphurous amino acids methionine and cysteine.
The sulphurous amino acid cysteine can be formed from the essential sulphurous amino acid methionine via a few steps. The presence of vitamin B6 and the amino acid serine is important for these conversions. The cysteine can then be converted to sulphite via oxidation and transamination. Finally, sulphate (necessary for sulphation) can be formed from this sulphite via oxidation.
Disruption of sulfur metabolism (sulphation) can lead to an increased permeability of the intestine, reduced back-up of substances (including sulphate) from the kidneys, problems with detoxification and neurological and allergic complaints. An upsetting sulfur metabolism has been found among other things in autistic children.1
The sulphate content (total and free) in the urine gives information about the 'loss' of sulphate via the urine. The degree of sulphation of the renal tubular proteins also determines how much sulphate can be re-absorbed and how much is excreted with the urine.
The test for free and total sulphate in blood (see under additional tests) can provide additional information.
Sulfite in the urine gives information about the level of sulphite intake via the diet and / or the body's ability to convert sulfite into sulphate (necessary for sulphation). For this conversion the molybdenum-containing enzyme sulphite oxidase is necessary, so that an indication can also be obtained for a potential molybdenum shortage.
Thiosulphate and thiocyanate in the urine: Thiosulphate detoxifies, among others, cyanide. Thereby thiocyanate is formed. The enzyme rhodanese is required for this conversion. The levels of these substances give (in combination) information about the load with the toxic cyanide and / or the ability to detoxify the cyanide. The toxic cyanide ion inhibits the oxidative phosphorylation and cellular oxidation, so that less ATP (energy) becomes available.