Lathyrism is caused by excessive consumption of

1. Basics of Human Nutrition: Macro and Micronutrients (basic)

At its core, nutrition is the process by which our bodies take in food and use it for growth, repair, and maintenance. The chemical substances found in food that perform these functions are called nutrients. Depending on the quantity our body requires and the role they play, these nutrients are categorized into two primary groups: Macronutrients and Micronutrients.

Macronutrients are the nutrients we need in large quantities every day. They provide the bulk of our energy (measured in calories) and the structural material for our tissues. These include Carbohydrates (primary energy source), Proteins (building blocks for growth and muscle repair), and Fats (long-term energy storage and cell protection). For example, foods like milk, curd, and paneer are vital sources of proteins and fats that help the body gain strength and ensure proper growth Science-Class VII, NCERT (Revised ed 2025), Adolescence: A Stage of Growth and Change, p.79.

Micronutrients, on the other hand, are required in much smaller amounts—often measured in milligrams or micrograms—but they are no less essential. They act as catalysts for various biochemical reactions. This group includes Vitamins and Minerals such as Iron, Zinc, Manganese, and Calcium Environment, Shankar IAS Academy (ed 10th), Agriculture, p.363. For instance, while we don't need pounds of Iron, a small amount is crucial for the formation of blood, just as Calcium is essential for bone development Science-Class VII, NCERT (Revised ed 2025), Adolescence: A Stage of Growth and Change, p.79.

Feature	Macronutrients	Micronutrients
Quantity Required	Large amounts (grams)	Small amounts (mg or μg)
Main Function	Energy production and structural growth	Biochemical regulation and disease prevention
Examples	Carbohydrates, Proteins, Fats	Vitamins (A, B, C, etc.) and Minerals (Iron, Calcium, Zinc)

A balanced diet is one that provides all these nutrients in the correct proportions. Relying too heavily on one group while neglecting another can lead to malnutrition or specific deficiency diseases. To maintain health, one should consume a variety of fruits, vegetables, and whole grains while avoiding processed or sugary foods Science, Class VIII, NCERT (Revised ed 2025), Health: The Ultimate Treasure, p.30.

Sources: Science-Class VII, NCERT (Revised ed 2025), Adolescence: A Stage of Growth and Change, p.79; Environment, Shankar IAS Academy (ed 10th), Agriculture, p.363; Science, Class VIII, NCERT (Revised ed 2025), Health: The Ultimate Treasure, p.30

2. Nutritional Deficiency Diseases (basic)

When we talk about nutrition, we aren't just talking about filling our stomachs; we are talking about providing the body with the specific chemical building blocks it needs to function. Nutritional deficiency diseases occur when the intake of essential nutrients—like vitamins, minerals, or proteins—falls below the required levels over a prolonged period. Unlike the flu or malaria, these are non-communicable diseases, meaning they cannot spread from person to person Science, Class VIII (NCERT 2025 ed.), Health: The Ultimate Treasure, p.36. They are often the result of a diet that lacks variety or the economic inability to access balanced meals.

Two of the most critical micronutrients often highlighted in public health are Iodine and Iron. Iodine is essential for the thyroid gland to synthesize thyroxin, a hormone that regulates metabolism. A deficiency in iodine can lead to Goitre, characterized by a visibly swollen neck Science, Class X (NCERT 2025 ed.), Control and Coordination, p.110. On the other hand, Iron deficiency is a major cause of anemia, a blood-related health problem that is particularly prevalent among adolescent girls and pregnant women, leading to fatigue and weakness Science, Class VII (NCERT 2025 ed.), Adolescence: A Stage of Growth and Change, p.80.

However, nutrition-related health issues aren't always just about "missing" a vitamin; sometimes, they arise from consuming specific toxins found in certain food substitutes used during famines. A classic example is Lathyrism (specifically neurolathyrism). This is a neurodegenerative disorder caused by the long-term consumption of Khesari dal (Lathyrus sativus). These seeds contain a neurotoxin called β-ODAP, which damages motor neurons, leading to progressive weakness and eventually paralysis of the lower limbs. Because Khesari dal is hardy and grows in poor soil, it often becomes a staple during droughts, leading to outbreaks of this crippling condition.

To help you remember the most common deficiencies, look at this quick reference guide:

Nutrient	Disease/Condition	Primary Symptom
Iodine	Goitre	Swollen thyroid gland (neck)
Iron	Anemia	Low hemoglobin, fatigue
β-ODAP Toxin	Lathyrism	Lower limb paralysis
Growth Hormone	Dwarfism	Stunted physical growth

Sources: Science, Class VII (NCERT 2025 ed.), Adolescence: A Stage of Growth and Change, p.80; Science, Class VIII (NCERT 2025 ed.), Health: The Ultimate Treasure, p.36; Science, Class X (NCERT 2025 ed.), Control and Coordination, p.110

3. Food Adulteration and Public Health Hazards (intermediate)

Food Adulteration is the practice of lowering the quality of food by adding inferior substances or removing vital nutrients. While some contamination is accidental, deliberate adulteration is a significant public health hazard in India. Because of its critical impact on population health, the subject of "adulteration of foodstuffs" is placed in the Concurrent List of the Constitution, allowing both the Union and State governments to legislate on it Indian Economy, Vivek Singh, Supply Chain and Food Processing Industry, p.373.

A classic and tragic example of a public health hazard caused by dietary habits is Lathyrism (Neurolathyrism). This is a neurodegenerative disorder caused by the prolonged consumption of Lathyrus sativus, commonly known as Khesari Dal or Grass Pea. This pulse contains a potent neurotoxin called β-ODAP (or BOAA), which acts as a glutamate analogue. When consumed in large quantities—often as a staple during famines when other crops fail—it leads to the permanent paralysis of the lower limbs by damaging the motor neurons in the spinal cord. This highlights how socio-economic factors like food scarcity can intersect with nutritional hazards to create localized epidemics.

To tackle such hazards, India moved from a fragmented regulatory system to a unified one. Historically, food was regulated by the Prevention of Food Adulteration (PFA) Act, 1954, but this was replaced by the Food Safety and Standards (FSS) Act, 2006. This new Act repealed several older orders, including those governing meat, milk, and edible oils, to establish the Food Safety and Standards Authority of India (FSSAI) Indian Economy, Vivek Singh, Supply Chain and Food Processing Industry, p.373. While FSSAI operates under the Ministry of Health and Family Welfare, it is an autonomous body led by a Chairperson, ensuring specialized oversight over everything from energy drinks (proprietary foods) to daily staples Environment, Shankar IAS Academy, Environment Issues and Health Effects, p.415.

Feature	Pre-2006 Era (PFA Act)	Post-2006 Era (FSS Act)
Structure	Multiple, overlapping laws (Meat, Milk, Oil orders).	Single, unified law (One Nation, One Regulator).
Focus	Prevention of Adulteration (Reactive).	Ensuring Food Safety and Standards (Proactive).
Regulator	Departmental oversight.	FSSAI (Autonomous Statutory Body).

Beyond chemical toxins like β-ODAP, unhygienic food and water are primary drivers of epidemics. In recent years, India has faced outbreaks such as the Acute Encephalitis Syndrome (AES) in Bihar, which claimed many lives, alongside viral threats like Nipah and Zika in Kerala Geography of India, Majid Husain, Contemporary Issues, p.37. Ensuring food safety is thus not just about preventing cheating in the market, but about national health security.

Sources: Indian Economy, Vivek Singh (7th ed. 2023-24), Supply Chain and Food Processing Industry, p.373-374; Environment, Shankar IAS Academy (10th ed.), Environment Issues and Health Effects, p.415; Geography of India, Majid Husain (9th ed.), Contemporary Issues, p.37

4. Environmental Contaminants and Bio-accumulation (intermediate)

When we talk about human nutrition, we must look beyond just calories and vitamins. In our modern environment, environmental contaminants often find their way into our food and water, turning essential consumption into a pathway for toxicity. This happens primarily through two processes: Bio-accumulation (the buildup of a toxin within a single organism over its lifetime) and Bio-magnification (the increasing concentration of that toxin as it moves up the food chain). As noted in Shankar IAS Academy, International Organisation and Conventions, p.411, substances like mercury are particularly dangerous because they are not easily excreted and thus impact the nervous system as they accumulate.

Heavy metals are the most notorious of these contaminants. Mercury (Hg), specifically in its organic form as methylmercury, was responsible for the Minamata disease in Japan, a severe neurological syndrome characterized by numbness and muscle weakness Shankar IAS Academy, Environment Issues and Health Effects, p.415. Similarly, Cadmium (Cd) contamination leads to Itai-Itai disease (literally "ouch-ouch" disease), which causes agonizing bone softening and kidney failure Shankar IAS Academy, Environmental Pollution, p.76. Lead (Pb) is another silent threat, often entering the body through old pipes or contaminated soil; it is known to cause anaemia and a distinctive bluish line around the gums, while also impairing mental development in children Shankar IAS Academy, Environmental Pollution, p.105.

Beyond industrial metals, certain natural contaminants in food staples can cause nutritional disasters. A prime example is Neurolathyrism, a neurodegenerative disorder caused by the long-term consumption of Khesari Dal (Lathyrus sativus). This pulse contains a neurotoxin known as β-ODAP (or BOAA). During times of famine, when this hardy crop becomes a staple, the toxin acts as an excitotoxin, damaging motor neurons and leading to permanent paralysis of the lower limbs. This highlights that nutrition is not just about what is present in the food (nutrients), but also what must be excluded (toxins).

Contaminant	Source/Vehicle	Key Health Impact
Mercury	Contaminated Fish	Minamata Disease (Neurological)
Cadmium	Mining runoff/Water	Itai-Itai Disease (Bone softening)
Lead	Pipes/Paint/Dust	Anaemia, Gum lines, Neuro-dysfunction
β-ODAP	Khesari Dal (Grass pea)	Neurolathyrism (Lower limb paralysis)

Sources: Environment, Shankar IAS Academy (10th Ed), International Organisation and Conventions, p.411; Environment, Shankar IAS Academy (10th Ed), Environment Issues and Health Effects, p.415-416; Environment, Shankar IAS Academy (10th Ed), Environmental Pollution, p.76, 105

5. Regulatory Framework: FSSAI and Food Safety (intermediate)

To understand food safety in India, we must first look at the legal transition from a fragmented system to a unified one. Before 2006, food regulation was a maze of different laws and orders, such as the Prevention of Food Adulteration Act (1954), the Fruit Products Order (1955), and the Meat Food Products Order (1973). To streamline this, the government enacted the Food Safety and Standards (FSS) Act, 2006, which repealed and consolidated these various central acts into one comprehensive framework Vivek Singh, Supply Chain and Food Processing Industry, p.373. This was a critical shift because the subject of "adulteration of foodstuffs" falls under the Concurrent List of the Indian Constitution, meaning both the Union and State governments have the power to regulate it Vivek Singh, Supply Chain and Food Processing Industry, p.373. Under this Act, the Food Safety and Standards Authority of India (FSSAI) was established in 2008. It is important to note that FSSAI is an autonomous statutory body; it does not function directly under the Director General of Health Services, but rather under the administrative charge of the Ministry of Health & Family Welfare Nitin Singhania, Food Processing Industry in India, p.411. The FSSAI logo on a food packet is more than just a label—it serves as a government-backed certification that the product has met minimum safety and quality standards, helping consumers make safe choices in the market NCERT Class VII Social Science, Understanding Markets, p.269. Beyond administrative rules, these regulations address severe public health risks caused by unsafe consumption. For example, the prolonged ingestion of Khesari Dal (Lathyrus sativus) can lead to Lathyrism, a neurodegenerative condition. This is caused by a neurotoxin in the seeds called β-ODAP (or BOAA), which leads to permanent paralysis of the lower limbs. Regulatory bans and monitoring by bodies like FSSAI are essential to prevent such toxic staples or adulterants from entering the food supply chain, especially during times of scarcity.

Sources: Indian Economy, Vivek Singh (7th ed. 2023-24), Supply Chain and Food Processing Industry, p.373-374; Indian Economy, Nitin Singhania (ed 2nd 2021-22), Food Processing Industry in India, p.411-412; Exploring Society: India and Beyond, Social Science-Class VII, NCERT (Revised ed 2025), Understanding Markets, p.269

6. Naturally Occurring Toxicants in Food (Phytotoxins) (exam-level)

While we often view plants solely as sources of nutrition, many species produce secondary metabolites known as phytotoxins as a defense mechanism against herbivores and pests. Just as common fruits and vegetables contain natural acids—such as the sour substances found in many edible items Science-Class VII . NCERT, Exploring Substances: Acidic, Basic, and Neutral, p.11—certain crops contain potent neurotoxic or growth-inhibiting compounds that can pose serious health risks to humans if consumed in large quantities or without proper processing.

A primary example of a naturally occurring toxicant is found in Lathyrus sativus, commonly known in India as Khesari Dal or grass pea. This crop is exceptionally hardy and drought-resistant, making it a reliable "famine food" when other crops fail Environment, Shankar IAS Academy, Agriculture, p.353. However, the seeds contain a dangerous non-protein amino acid called β-ODAP (or BOAA). Because β-ODAP is a structural analogue of the neurotransmitter glutamate, it acts as an excitotoxin, overstimulating and eventually damaging the motor neurons in the spinal cord.

The resulting clinical condition is known as Neurolathyrism. This is a neurodegenerative disorder characterized by progressive, irreversible weakness and spastic paralysis of the lower limbs. Historically, outbreaks occurred during periods of drought or famine when people were forced to rely on Khesari dal as their primary staple. This led several Indian states to implement bans on the sale of the pulse to protect public health, reflecting a broader concern about toxic substances entering our bodies through our diet Science, class X (NCERT), Our Environment, p.212.

Feature	Neurolathyrism Details
Causative Agent	β-oxalyl-L-α,β-diaminopropionic acid (β-ODAP)
Primary Source	Khesari Dal (Grass Pea / Lathyrus sativus)
Main Symptom	Spastic paraplegia (paralysis of the lower limbs)
Risk Factor	Prolonged consumption as a staple (often during famines)

It is important to note that while other crops like Cassava (Tapioca) also contain naturally occurring toxicants (specifically cyanogenic glycosides) Environment and Ecology, Majid Hussain, Major Crops and Cropping Patterns in India, p.87, the specific neurological damage associated with grass pea remains a unique and significant public health challenge in tropical agriculture.

Sources: Science-Class VII . NCERT(Revised ed 2025), Exploring Substances: Acidic, Basic, and Neutral, p.11; Science , class X (NCERT 2025 ed.), Our Environment, p.212; Environment, Shankar IAS Acedemy .(ed 10th), Agriculture, p.353; Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Major Crops and Cropping Patterns in India, p.87

7. Lathyrus Sativus and Neurolathyrism (exam-level)

Lathyrus sativus, commonly known as the grass pea or Khesari dal in India, is a remarkably hardy legume. It is often referred to as a 'famine food' because of its ability to thrive in extreme drought and poor soil conditions where other crops fail. While it is a rich source of protein, its prolonged and exclusive consumption (especially during periods of food scarcity) is linked to a serious neurological condition known as neurolathyrism. This illustrates a critical principle in human nutrition: the presence of anti-nutritional factors or natural toxins in otherwise edible plants can have devastating health consequences if not managed correctly.

The culprit behind this condition is a non-protein amino acid called β-oxalyl-L-α,β-diaminopropionic acid, abbreviated as β-ODAP (or BOAA). This chemical acts as a neurotoxin. Specifically, β-ODAP is a structural analogue of glutamate, a primary neurotransmitter in the brain. When ingested in large quantities over 2–3 months, it causes excitotoxicity—overstimulating and eventually damaging the motor neurons in the spinal cord. This lead to a specific type of 'sign'—something a doctor can measure, like muscle spasticity—and 'symptoms' like the feeling of leg weakness Science Class VIII NCERT, Health: The Ultimate Treasure, p.31.

The physical manifestation of neurolathyrism is spastic paraplegia, characterized by a progressive weakness and irreversible paralysis of the lower limbs. Unlike general neuromuscular effects seen in heavy metal poisoning (such as the 'lead palsy' or muscular atrophy associated with lead toxicity), neurolathyrism specifically targets the motor pathways, often resulting in a characteristic 'scissor gait' Shankar IAS Academy, Environment Issues and Health Effects, p.413. Because of these risks, the sale of Khesari dal was historically banned in many Indian states, though modern agricultural science is now focusing on developing low-ODAP varieties to harness the crop’s climate-resilient benefits safely.

Feature	Neurolathyrism Details
Causative Agent	β-ODAP (a neurotoxin in Lathyrus sativus)
Primary Symptom	Progressive paralysis of lower limbs (Spastic paraplegia)
Mechanism	Excitotoxic damage to motor neurons in the spinal cord
Risk Factor	Monotonous diet of Khesari dal during famines/poverty

Sources: Science Class VIII NCERT, Health: The Ultimate Treasure, p.31; Shankar IAS Academy, Environment Issues and Health Effects, p.413

8. Solving the Original PYQ (exam-level)

Now that you have mastered the concepts of nutritional toxicology and the biology of "famine foods," this question serves as a perfect application of how environmental stressors impact human health. Lathyrism is a classic example of a neurodegenerative condition that arises when a specific pulse, Lathyrus sativus, becomes the primary dietary staple due to its extreme drought resistance. During your study of plant toxins, you encountered β-ODAP (or BOAA), a potent neurotoxin. The name of the disease itself is a direct linguistic clue pointing to the genus Lathyrus, which logically identifies (A) Kesari dal (the common name for the grass pea) as the correct answer.

To arrive at this conclusion, a seasoned aspirant looks for the specific mechanism of motor neuron damage. While Kesari dal is nutritionally dense and hardy, its over-consumption leads to the irreversible paralysis of the lower limbs. Always look for the connection between a crop's resilience and the socio-economic context of the disease, as this is a recurring theme in UPSC biology and geography questions. As noted in ScienceDirect, this excitotoxic damage is what distinguishes lathyrism from simple vitamin deficiencies or acute bacterial food poisoning.

UPSC frequently includes distractors related to other famous food-borne health crises to test your precision. For instance, Mustard oil is a common trap because it is associated with Epidemic Dropsy (caused by Argemone oil adulteration), while Polished rice is the classic culprit for Beriberi due to the loss of Vitamin B1 (Thiamine). Mushrooms are often included as a generic distractor to lure students toward general "poisoning" theories. By isolating the specific neurotoxic link to the Lathyrus genus, you can confidently navigate through these standard UPSC traps.