Lathyrism, a neurological disease leading to paralysis of lower limbs, is caused by the excessive and prolonged consumption of which of the following food items?

Introduction / Context:
Lathyrism is a neurological disorder historically observed in populations that rely heavily on certain pulses as a staple food, especially during famines and food shortages. It is characterised by spastic paralysis and weakness of the lower limbs. Public health and nutrition questions often ask which particular pulse is associated with this disease. This question focuses on identifying the food item whose excessive consumption can cause lathyrism.

Given Data / Assumptions:

• Lathyrism is linked to a toxin present in a specific pulse.
• The options include Khesari dal, mustard oil, mushrooms, polished rice, and groundnut oil.
• We assume chronic consumption over months or years, especially when dietary diversity is poor.
• Only one of these items contains the neurotoxic compound associated with lathyrism.

Concept / Approach:
Khesari dal is the common name for the seeds of Lathyrus sativus, a legume that can grow in poor soils and drought conditions. It contains a neurotoxin (often referred to as BOAA or related compounds) that can damage motor neurons when consumed in large quantities over time. This leads to lathyrism, characterised by stiffness and paralysis of the legs. Mustard oil, mushrooms, polished rice, and groundnut oil can have other health concerns if misused, but they are not associated with lathyrism in standard medical literature. Therefore, the correct answer is Khesari dal.

Step-by-Step Solution:
Step 1: Recall the definition of lathyrism: a crippling disease causing spastic paralysis of the lower limbs due to a neurotoxin.Step 2: Identify that this disease has historically been associated with consumption of Lathyrus sativus seeds, known as Khesari dal.Step 3: Mustard oil is used as an edible oil and can cause other issues if adulterated but is not the cause of lathyrism.Step 4: Mushrooms can cause poisoning if toxic varieties are eaten, but this is different from chronic lathyrism.Step 5: Polished rice is linked with vitamin B1 deficiency and beriberi when it dominates the diet, not with lathyrism.Step 6: Groundnut oil is a common cooking oil and is not the classical cause of lathyrism.Step 7: Thus, select Khesari dal (Lathyrus sativus) as the correct answer.

Verification / Alternative check:
Nutrition and public health references clearly mention lathyrism as a disease associated with excessive intake of the pulse Lathyrus sativus. The disease has been observed in regions where Khesari dal was consumed heavily due to food scarcity. Government advisories in some countries have even restricted or discouraged its sale. No authentic source associates lathyrism with mustard oil, mushrooms, polished rice, or groundnut oil, which confirms that Khesari dal is the causative food.

Why Other Options Are Wrong:
Mustard oil can cause health problems if adulterated, but it is not the classic cause of lathyrism.Mushrooms may cause acute poisoning, but these effects are different and not specifically lathyrism.Polished rice is linked with beriberi due to thiamine deficiency, not with lathyrism.Groundnut oil is not associated with this particular neurological disorder in standard medical texts.

Common Pitfalls:
Students sometimes confuse lathyrism with other deficiency diseases like beriberi, pellagra, or ergotism and may pick polished rice or mushrooms. Others may guess mustard oil because it is a common food item. To avoid such mistakes, memorise the classic pairings in nutrition: Khesari dal with lathyrism, polished rice with beriberi, and so on. This will help you quickly identify the correct answer in similar questions.

Final Answer:
The correct answer is Khesari dal (Lathyrus sativus).