Covert trade in toxic vetch continues
ref. Nature 400 (6742):207 (1999)
The Commentary "A mess of red pottage" by two of us1 exposed the export from Australia of seeds from toxic common vetch (Vicia sativa ) as a cheap substitute for the edible red lentil (Lens culinaris). Despite curbs to this trade in the wake of our article, the problem has recurred.
Dietary cyanoalanine neurotoxins from vetch, accumulate in the brains and livers of pigs, rats and poultry. Effects on sulfur metabolism, result in urinary excretion of cystathionine and accumulation of the nonfunctional glutathione analogue, g-glutamyl-b-cyanoalanyl-glycine. Correspondence by E.G.Brown2 pointed out that the genetic predisposition towards favism in Mediterranean communities made this doubly unfortunate, because common vetch also contains the favism toxin vicine.
After our Commentary was published, India and Egypt banned its importation, and Saudi Arabia restricted imports of vetch. The Victorian Weekly Times published articles entitled "Scientists cripple vetch industry", and "Vetch now unfit for humans to eat ".The A$18 million (US$11.7 million) market collapsed.
Last year, we were alerted by the Sri Lankan Health Department of the problemís re-emergence. Unlabelled bags of split red vetch (240 tonnes) had been exported from Adelaide via Johor (Malaysia) to Colombo. Upon arrival the container documentation had been altered from "red split vetch" to "red split lentils". This event was extensively reported in the Sri Lankan Daily News3, but was ignored by the international media. In April 1999 a report on Australian radio4 gave details of the multithousand tonne vetch/lentil substitution racket. The export price ($A340-400/mt), leaves no doubt that the bulk is sold for human consumption.
Exports (in tonnes) from South Australia for the first four months of 1999 include: Split vetch to Yemen (22) and United Arab Emirates (194) and "Whole vetch": Argentina (10), Bangladesh (989), Belgium (187), Germany (63), Italy (149), Japan (120), Mexico (40) Netherlands (124), Pakistan (903), Phillipines (22), Portugal (106), South Africa (42), Taiwan (86).
From these data and the sale of unlabelled split red vetch in the markets of Pakistan and Bangladesh, we conclude that either it is being split in the importing country or it is being split in Australia and exported in bags labelled whole vetch.
When cooked (without leaching) in mistake for red lentils, each thousand tonnes equates to ten million 100g platefuls containing 0.5g of cyanoalanine toxins. The harmful effects of vetch consumption in animals are known, but the effects on humans are not. Most at risk are malnourished vegetarian societies with sulfur deficient diets.
To protect a valuable
and expanding lentil industry, the Australian government has moved swiftly
(7th April 1999) to declare both vetch and lentils as prescribed grains.
This means that inspection and phytosanitary certidfication are mandatory
before export. Unfortunately the financial rewards to both exporters and
importers are still too high to completely eliminate this dishonest trade.
1. Nature 359, 357-8, (1992). 2. Nature, 360, 9, (1992) 3. http//www.lanka.net/lakehouse/archive.html (8 October 1998).
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