Analysis, occurrence, and toxicity of ß-methylaminoalanine (BMAA)

A risk for the consumer?

image of Analysis, occurrence, and toxicity of ß-methylaminoalanine (BMAA)

In 2005 an international research team reported that cyanobacteria living in symbiosis with plants or living free in lakes and oceans are able to produce the non-protein amino acid -methylaminoalanine, also known as BMAA. Some years earlier the American scientists in this team had reported that BMAA could be found not only in the brain from diseased patients of the Chamorro people on Guam having the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and Parkinsons dementia (PD), but also in two patients with Alzheimers disease in Canada. A very high incidence of ALS and PD among the Chamorro people had been known since after the Second World War and had been linked to the use of flour prepared from the seeds of the local cycad tree, which had been shown to contain BMAA. As surface water is frequently purified and used as drinking water, it was hypothesised that low level of contamination of drinking water with BMAA from the cyanobacteria might reach the human brain and over time result in neurodegenerative disease. This reports aimed at scrutinizing this hypothesis, and concludes that BMAA is unlikely to occur in drinking water and be responsible for these neurological diseases in the Western World.



Summaries of epidemiological studies

Steele and Guzman (1987) observed that the ALS/PD complex only occurred where cycad trees grow and where people use its seeds for food and medicine. They provided an explanation for the rarity of the disease on the island of Saipan. During Spanish and German administrations, before 1914, cycad trees were abundant and people used cycad flour in the same way as the people of Guam and Rota did. When the Japanese occupied Saipan in 1914 they cleared large parts of the island for sugar plantation and by the 1920s most of the cycad forests had been cut down. When neurological surveillance teams visited Saipan in the 1950s cycad flour had not been used on the island for 30 years. At that time ALS was less common there than on Guam or Rota, and Saipanese people that suffered the disease were born before 1917. Another fact that is related is that the disease was not seen in Filipinos who arrived on Guam after 1950, when the flour ceased to be a staple food. Interwievs that Steele and Guzman conducted suggested that familial aggregation of patients could relate to differences between families in the method of preparing the cycad seeds. There appeared to be considerable differences in regard to the soaking process and the number of water changes between families (Steele and Guzman, 1987).


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