Cycads and Guam Disease
Peter Lister & K.D. Hill
Medical records for the island of Guam from 1936 demonstrate a high
incidence of Alzheimer's, Parkinson's and Motor Neurone
Disease. The three combined are known as 'Guam disease'.
Research has centred upon the township of Umatac.
Around 1980, Prof. Leonard Kurland of the Mayo Clinic
asked the anthropologist, Marjory Whiting (who
was visiting Guam) to examine the diet of the locals for about
a month. This research formed the foundation of further investigation.
Whiting recorded the methods of preparation of seed of
"Cycas circinalis" (correctly C. micronesica)
as she suspected it was the cause of the problems.
(see Laqueur et al. 1963).
Seed was collected, the kernel removed and soaked for 7-9 days.
It was then cut into smaller pieces and soaked for another week.
Removed, cut again and soaked for another week, then sliced and
rinsed with water until the water was no longer milky. The water
was changed every day during this month-long procedure. They also
gave residues of the rinsing to chickens. If they fell ill,
then it needed more rinsing!!! When it was ready, the pieces were
dried, ground to a flour and made into what the locals called "tortillas".
London botanist Arthur Bell also analysed the seed of Cycas circinalis
and determined it to contain the same toxin as in Lathyrus in India,
which caused a degenerative crippling disease known as Lathyrism.
The toxic compound was identified as
Chemist Peter Nunn used BMAA in clinical trials on rats and found that
there was no effect after 70 days.
Meanwhile, similar disease symptoms had been found in patients
in Kii Peninsula in Japan and on the River Ia in New Guinea. There
were no records of Cycas having been eaten in either area, and patients
were adamant that it formed no part of the diet. Researchers started
looking for other causes and the search started to focus upon soils.
In Japan, the soils were extremely high in Aluminium and low in
Calcium, so it was suggested that this may be the cause of the symptoms.
New York neurotoxicologist Peter Spencer visited India in 1980 to examine
patients with lathyrism (mentioned earlier).
Spencer and Nunn collaborated, and they returned
to looking at BMAA. They found that it affected living rat
nerve cells in culture - it acted as a cytotoxin and there was
massive cell death within seconds of it being administered. They fed it
to monkeys in their food and found symptoms appearing after one
month - the same as those experienced by patients in Guam.
(see Spencer et al. 1987).
In the Kii Peninsula, they found cycads to have been used in the
past as a pharmaceutical, a herbal remedy for stomach ache and
to "increase strength", although used rarely.
There were also cycads growing in
older gardens, and they found the mother of a patient whom had
been prescribed cycad as a child. It had been administered by her
grandmother at the age of about 5 and she died when 25, suffering
motor neurone disease.
In New Guinea, Valerie Palmer worked with Spencer in various villages
and found cycad seed to be used in aiding the healing of wounds.
Raw, unwashed seed was pounded to a pulp and applied directly as
a poultice to cuts and ulcerous wounds, held in placed by a leaf
and bound with plant fibre.
Their continued work demonstrated there could be up to 35 year
latency in the effects
(see Kurland 1988).
They found patients in Guam whom had been
violently ill as a child from the consumption of cycad on one
ocassion, and never eaten it again, but died 36 years later
suffering all the symptoms.
In 1988, Peter Nunn again visited Guam. His observations of the
preparation of cycad seed noted large amounts of gas given off in
the first 3 days of soaking. Cyanide was suggested as being implicated
in the poisoning. Symptoms of poisoning included vomiting, dizziness