Hawaii-based Cyanotech took the unusual step of commissioning independent testing from Professor Wayne Carmichael of the Department of Biological Sciences at Wright State University following the publication of an article entitled "Diverse taxa of cyanobacteria produce b-N-methylamino-L-Alanine, a neurotoxic amino acid" in the April 2005 issue of the Proceedings of the National Academy of Sciences (PNAS 102:5074-5078).
Ninety-seven percent of the free-living cyanobacteria strains tested and 73 percent of the strains isolated from symbiosis were shown to produce BMAA, but spirulina, blue-green vegetable algae rich in beta carotene, iron, vitamin B12 and gamma linolenic acid, was not included in the study.
Cyanotech chairman, president and CEO Gerald Cysewski told NutraIngredients-USA.com that the omission was "unfortunate" - even though the study was carried out on live laboratory cultures of cyanobacteria, making it impossible to draw a correlation with spirulina dietary supplements.
Despite this, Cyanotech and competitor Earthrise feared that the article could have a negative impact on business.
"The results of the test confirm that our Spirulina contains no trace of BMAA and we are pleased to provide this reassurance to our customers of the integrity of our products," said Dr Cysewski.
The companies initially contacted the article's author Dr Paul Cox of Califiornia State University to request that his study be expanded to include spirulina but, after receiving no response, commissioned Dr Carmichael to carry out the test instead.
Dr Cox and colleagues not only identified a link between BMAA and an Alzheimer's-like disease suffered by the Chamorro people of Guam, who eat the seeds of BMAA-producing cycad plants, but also said that their data demonstrate that BMAA is produced by cyanobacteria from geographical regions and diverse environments throughout the world.
"Because cyanobacteria function as primary producers in many food chains, it is likely that human populations far from Guam may be exposed to this environmental neurotoxin," they wrote.
"This suggestion is partially corroborated by the discovery of BMAA in brain tissues of Canadian Alzheimer's patients."
They advocated the monitoring of BMAA in sources of drinking water and in invertebrates, fish, or grazing animals used for human consumption that either directly consume cyanobacteria or forage on plants or prey that may have accumulated cyanobacteria-produced BMAA.