I wrote here on Hydrogen Sulfide SIBO, a third kind of SIBO that I am finding in many of my patients. Since molybdenum is a cofactor for the sulfite oxidase enzyme that requires support, it is usually included in the protocol. However, I’ve found that a small handful of people cannot tolerate this nutrient, due to (so far) rare side effects of headaches or eczema.
This appears to be why.
Molybdenum as a Cofactor
Molybdenum is a cofactor (or a necessary nutrient) for four enzymatic reactions. Think of cofactors like a key to an engine, where the engine is the enzyme.
First, it’s a cofactor for sulfite oxidase, the enzyme responsible for taking sulfites from sulfur-containing amino acids in foods, and turning them into sulfates. This is the reason it’s helpful for H2S SIBO, as in that case, the body is presumably increasing production of a sulfur-containing gas as a way to bypass the enzyme that isn’t working as well as it should.
But molybdenum is also a cofactor for three other enzymes. One is aldehyde oxidase, which breaks down aldehydes, potentially toxic compounds found in foods and alcohol, as well as in pharmaceuticals. Another is a poorly understood enzyme called mitochondrial amidoxime reducing component (which is why they abbreviate it mARC!), which appears to help with elimination of toxic metabolic waste.
The last enzyme appears to be the reason for the problem: xanthine oxidase. Xanthine is a breakdown product of nucleic acids (the building blocks of DNA), and the enzyme breaks it down into uric acid.
Uric Acid Symptoms
Uric acid is best known as the causative agent in gout, causing inflamed and painful joints due to uric acid crystals that precipitate out in the joint space when uric acid levels in the bloodstream are too high for the kidneys to completely eliminate. High uric acid and gout usually occur after consuming foods high in purines, the nitrogen bases that also hold DNA together. These foods include particularly alcohol, seafood, and meat.
But high uric acid can cause less common symptoms too at lower levels, such as eczema and headaches, including migraines.
Since molybdenum is a cofactor for the xanthine oxidase enzyme that increases production of uric acid, I suspect that these unusual side effects of molybdenum are a result of the sudden relative increase of uric acid, even though it’s below the threshold that might otherwise cause gout. If that’s the case, natural xanthine oxidase inhibitors like cherries or cherry juice should relieve the symptoms.