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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 BMAA (B-methylamino-L-alanine).
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 and weakness.
| The Cycad Pages © 1998 Royal Botanic Gardens Sydney Written and maintained by Ken Hill Please send comments and corrections |