Proton magnetic resonance spectroscopy (MRS) revealed a distinct resonance at 3.15 ppm in the brain of a 5-year-old male diagnosed with autism. The resonance assignment is attributable to ingestion of methylsulfonylmethane (MSM) as a dietary supplement. Glucosamine with MSM is marketed as a source of dietary sulfur and treatment of joint pain. Recognition of this chemical on brain proton MRS as an exogenous compound is necessary to avoid confusion as a pathologic metabolite of pediatric metabolic disease.
The first and only toxicology study of MSM (OptiMSM, Bergstrom Nutrition, Vancouver, WA) to be published in a peer-reviewed journal. Published in the Journal of Food & Chemical Toxicology. GLP-compliant. No adverse effects were noted in either acute or subchronic (90) studies at dose levels of 2 g/kg in the acute phase and 1.5 g/kg in the subchronic phase. Toxicology, lab, gross pathology, histology were all negative.
Concern has been raised based on the results of this in vitrostudy, which found meiosis was interrupted in early gametogenesis in the nematode Caenorhabditis elegans (C. elegans is a small (about 1 millimeter), primitive worm that shares certain essential biological characteristics with humans (e.g., it produces sperm and eggs, reproduces, has a nervous system, etc.). Its short lifespan, rapid development, and easy cultivation under controlled conditions make it a favorite of research scientists as a model for toxicologic assays. When it was grown in concentrations of MSM exceeding 1%. Increasing concentrations of MSM impaired the fecundity and viability of treated worms. This study is actually attempting to suggest the possibility of a teratogenic effect. However, more definitive research has shown no teratogenic effects or developmental toxicity.
In vivo magnetic resonance spectroscopy (MRS) was used to detect and quantify MSM in the brains of four patients with memory loss and in three normal volunteers all of who had ingested MSM at the recommended doses of 1-3 g daily. MSM was detected in all subjects at concentrations of 0.42-3.40 mmole/kg brain and was equally distributed between gray and white matter. MSM was undetectable in drug-naive normal subjects (N=25), patients screened for 'toxic exposure' (N=50) or patients examined with 1H MRS for the diagnosis of probable Alzheimer Disease (N=520) between 1991 and 2001. No adverse clinical or neurochemical effects were observed. Appearance of MSM in significant concentrations in the human brain indicates ready transfer across the intact blood-brain barrier.
Study to assess acute intragastric toxicity of MSM. LD50 could not be established because even the maximum dose of 20g/kg failed to kill any of the animals (n = 10); no adverse effects were noted (the maximum recommended dose in humans approximates 300mg/kg).