Grass pea, Guaya in Amharic, is one of the several species of the genus Lathyrus. The crop is known to have grown in several parts of the world including North and East Africa, Southeast Asia,
the Middle East, and in other parts of Europe, North and South America and Australia. Grass pea has an ability to withstand adverse environmental conditions including drought, to provide yield with limited amount of moisture, and to resist pests and weeds. It is also known for its enormous nutritional content.
Studies indicate that Ethiopia is the oldest growing homeland as well as the largest producer and consumer in Africa. The crop mainly grows in West, South and East Tigray; North and South Gonder; North and South Wello; East and West Gojam; and North, West and East Shewa.
Despite its enormous contribution in combating food scarcity in drought-prone areas by serving as a source of nutrition for the poor, grass pea is the known to be the cause of Lathrysm – an irreversible neurodegenerative disease, essentially manifested in spastic paraparesis of the lower limbs in humans. Research activities carried out on the disease indicate that Human Lathrysm Syndrome (HLS) causes reduced mobility, scissor gait, turning-in of the toes, stiffness, and semi-flexion of the knee joints.
Dr. Asnake Fikre is a researcher at Ethiopian Institute of Agricultural Researches who conducted a vast research on grass pea and its toxic consequences in various parts of the country where grass pea is grown. He explains that Ethiopia is known to the most frequent victim of the toxicity in Africa, and mentions several instance of Lathrysm in Ethiopia. He said in North and Northwest Ethiopia, where the disease occurred in the form of epidemic, several people have been victims of the toxic effect of the crop, and more than 5,000 people in Denbia, Fogera, Wadla Delanta have been victims in 1960 and 1987 E.C.
Dr. Asnake contends that the occurrence of health problems as a result of consuming grass pea is directly associated with the mode of nutrition/consumption followed by its consumers. He says the proportion of grass pea in meals determines the chance of acquiring the disease, noting a huge probability of acquiring the disease that comes if grass pea constitutes more than one third of the total meal consumption of an individual.
Consumption of unprocessed forms of grass pea such as green pea, roasted seed, and boiled seed increases the chance of the consumer to be exposed to Lathrysm, as the toxic content is still unreduced within the grains, says Dr. Asnake. He also states that there exists an extensive misconception and fear among the society that Lathrysm can be caused by exposing oneself to the steam coming out of boiling grass pea, through prolonged contact with moist straw, or by consuming raw grass pea with milk. He is of the contention that though research findings indicate a certain degree of presence of ODAP is in the steam of boiling grass pea, no scientific evidences have shown the possibility of acquiring the disease through its exposure.
The gist of the research findings is that the damage caused to humans by grass pea is mainly attributed to failures to follow appropriate mode of processing the crop for consumption purposes. If the consumption of grass pea is limited to less than half of the total diet supplemented with cereals that are richer in the essential amino acids deficient in grass pea, the chances of developing Lathrysm are minimal, he says.
On the other hand, the unavailability of such important information as to the proper utilization of the crop among the society coupled with the ever-existed and dominant misconception of the disadvantages of the crop has, according to Dr. Asnake, contributed to the prevalence of such problem.
As to research efforts to replace the crop with better varieties, he says while it has not yet been possible to produce cultivars that are completely free from toxic elements, varieties with less threshold of toxicity have been generated both abroad and in the country. He says the distribution of such varieties has not been done in a wider scale, mainly due to the high out-crossing (>20-25 percent) nature of grass pea, entailing the need for a new method and system of production. In a nut shell, Dr. Asnake believes that grass pea is not an evil crop; its valuable aspects can be promoted through its agricultural benefit arising from its suitability for double cropping, its ability to grow in degraded lands, requirement of less cost and labor for production, ability to provide high yield even when compared to other crops requiring a relatively more care, as well as its resistance to diseases.
As to the medical point of view, the occurrence of Lathrysm has remained unreported until recent times while its harm in the society can be easily felt. The socio-traditional influence and discrimination on the victims of the disease, which, according to Dr. Asnake, has been a factor for the occurrence of feeling of inferiority, poverty, and unproductiveness among the affected society. Finally, Dr. Asnake stated that if every concerned body discharges its responsibility to avert this situation, especially by making relevant and scientific information available to the society, it is possible to stop the occurrence disease once and for all, and enable those affected by the disease to do their part in the development of their country.