Multiple neurotoxic items in the Chamorro diet link BMAA with ALS/PDC.

Beta-methyl-amino-L-alanine, (BMAA), is found in multiple components of the traditional Chamorro diet of Guam and this confounds epidemiological analysis based on a single dietary item. However, using hair as a non-invasive measure of BMAA exposure may help determine risks for developing motor neuron disease. BMAA found in brain tissues of patients with ALS/PDC and not generally in controls suggests that BMAA crosses the blood-brain barrier in patients with disease and is associated with neurodegenerative disease. An examination of frozen versus fixed autopsy tissue from ALS/PDC patients suggests that earlier studies of BMAA in ALS/PDC patients based on fixed tissues may have underestimated the concentration of BMAA in brain tissues. We suggest that the Chamorro people are exposed to chronically low levels of BMAA in the diet and that further research is needed to understand chronic BMAA toxicity.