Study links
eating bat
to diseaseGuamanians who eat bats
at traditional feasts have a
high incidence of dementia
Bats with a wingspan of up to four feet, boiled in coconut cream and eaten whole, are linked to the exceptionally high rate of a form of Parkinson's disease on Guam, a new scientific study confirms.
Scientists have long suspected a link between Guamanians' consumption of the bats known as flying foxes and their high rate of a form of Parkinson's. The study, to be published today in the Proceedings of the National Academy of Sciences, confirms that the neurotoxic nonprotein amino acid BMAA, found in Chamorros with Parkinson's, is contained in the cycad tree, whose seeds the winged mammals eat.
Dr. Paul Cox, the director of the National Tropical Botanical Garden on Kauai and the leader of the study, said analysis shows that the seeds must be eaten by the bats before the neurotoxin transfers to humans. Eating foods made from cycad seeds, including tortillas popular in Guam, would require massive amounts to be dangerous, Cox said.
The same neurotoxin, however, has been found in brain tissue from two Canadians who died of Alzheimer's and have no connection to Guam. It is the first time BMAA has been found outside of the cycad tree, Cox said.
But Cox said no conclusions can be drawn yet from the Canadian discovery.
"Although we think we have established a link between a dietary neurotoxin and the disease among the Chamorro," Cox said, "we have only opened a door that other scientists will need to go through in a long path to coming up with a therapy."
For more than a decade, Cox and other researchers have been trying to find out why the incidence of neurological disease ALS-parkinsonism dementia complex among Guamanians from the 1940s to 1970s was 100 times higher than elsewhere.
Previous studies by Cox, an ethnobiologist, and Oliver Sacks, the inspiration for the neurologist in the movie "Awakenings," found evidence that the native Chamorros were exposed to the neurotoxin by eating the bats -- brains, fur, wings and all -- at traditional feasts.
The new study examined victims of neurological disease in Guam and compared them with a group of 15 Canadians. The study found the neurotoxin originating in the cycad tree in the brain tissue of people who died with Parkinson's or Alzheimer's but not in those who were healthy.
Among the Canadians, the neurotoxin was found only in the two who died of Alzheimer's.
Cox said the study confirms that the neurotoxin was working its way up the food chain and, through a process of biomagnification, exposing humans to neurodegenerative diseases such as Parkinson's and Alzheimer's.
ALS-parkinsonism dementia complex, called lotico-bodig on Guam, is similar to a number of ALS-like conditions, such as Parkinson's and Alzheimer's diseases.
