Public Release: 

National Tropical Botanical Garden reports possible dietary link and neurodegenerative disease

Research may yield insights into Alzheimer's, ALS & Parkinson's

Edelman Public Relations

Kalaheo, HI - November 10, 2003 - A study published in today's online Proceedings of the National Academy of Sciences suggests a possible dietary link to a devastating neurological disease that has long afflicted the Chamorro population of Guam. Drs. Paul Alan Cox, Sandra Banack, and Susan J. Murch of the National Tropical Botanical Garden's Institute for Ethnobotany in Hawaii found that a neurotoxin (BMAA) produced by cyanobacteria, which lives in the roots of the Guamanian cycad tree, accumulates in the food chain of the Chamorros - a process known as biomagnification. This was confirmed when the researchers discovered BMAA in the brain tissue of Chamorros who died from the disease, amyotrophic lateral sclerosis-Parkinsonism dementia complex (ALS-PDC).

"Drs. Banack, Murch and I found BMAA in increasingly higher concentrations as it moved up the food chain to the Chamarros - up to 1,000 times higher in their food source than in the cyanobacteria," said Dr. Cox, Director of the Institute for Ethnobotany. "Our study shows there is a link between cyanobacterial BMAA and Guamanian ALS-PDC."

People with ALS-PDC may exhibit symptoms of amyotrophic lateral sclerosis (ALS; also known as Lou Gehrig's disease), Alzheimer's, and Parkinson's disease. ALS-PDC is virtually limited to the Chamorro people of Guam, and at one time, occurred at 50 to100 times the rate of ALS elsewhere.

Previous research1 by Dr. Cox and the neurologist Oliver Sacks, M.D., suggests that the Chamorros were exposed to BMAA through consumption of a type of bat, flying foxes, which feed on cycad seeds. They also theorized that biomagnification occurred, in which neurotoxins accumulate in successively higher levels from cycad seeds to flying foxes to the Chamorro people.

Dr. Cox likens the biomagnification of BMAA, an amino acid once found only in cycads, to the biomagnification of mercury, DDT, PCBs, and other pesticides and pollutants that accumulate to often dangerous levels in birds and fish.

Dr. Cox and his team also discovered that BMAA appeared in Canadian patients with neurodegenerative disease. He said it was too early to speculate on the significance of the finding, and further research was needed.


About the National Tropical Botanical Garden's Institute for Ethnobotany

The Institute for Ethnobotany focuses on studying the interaction between plants and indigenous people. It is based at the National Tropical Botanical Garden (NTBG), a Congressionally-chartered system of five gardens in Hawaii and Florida.

Dr. Cox is the Executive Director of the NTBG. Dr. Banack, an Associate Professor at California State University, is a Research Associate at the Institute. Dr. Murch, a biochemist from the University of Guelph in Ontario, Canada, is a Senior Research Associate at the Institute.

The initial research by Drs. Cox, Banack and Murch was funded in part by a grant from the ALS Association.

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