Nutritional Disorders

& Clinical Significance

Nutritional disorders arise due to imbalances in nutrient intake, absorption, or utilization, leading to undernutrition, overnutrition, or specific deficiencies. These disorders significantly impact health, contributing to morbidity and mortality globally. Understanding these disorders is crucial for medical students as they form the basis of preventive and therapeutic medicine.

1. Protein-energy malnutrition (PEM)

Definition: A condition caused by inadequate intake of protein and energy, common in developing countries.

• Types:

  • Kwashiorkor: Protein deficiency with adequate calorie intake.

  • Marasmus: Severe calorie and protein deficiency.

Clinical Features:

• Kwashiorkor: Edema, fatty liver, hair changes, apathy, and dermatosis.

• Marasmus: Wasting of muscle and fat, stunted growth, and weakened immunity.

Clinical Significance:

• Increased susceptibility to infections (e.g., pneumonia, diarrhea).

• Long-term developmental delays in children.

Management:

• Nutritional rehabilitation with energy-dense, protein-rich diets.

• Treat underlying infections and deficiencies.

2. Micronutrient Deficiencies

A. Vitamin Deficiencies

1. Vitamin A Deficiency:

   • Symptoms: Night blindness, xerophthalmia, Bitot’s spots.

   • Clinical Significance: Leading cause of preventable childhood blindness.

   • Treatment: Vitamin A supplementation and dietary sources (carrots, spinach).

2. Vitamin D Deficiency:

   • Symptoms: Rickets in children, osteomalacia in adults.

   • Clinical Significance: Causes bone deformities and fractures.

   • Treatment: Vitamin D supplements and sunlight exposure.

3. Vitamin C Deficiency:

   • Symptoms: Scurvy—bleeding gums, poor wound healing, and petechiae.

   • Clinical Significance: Impaired collagen synthesis leads to tissue fragility.

   • Treatment: Vitamin C-rich foods (citrus fruits, bell peppers).

4. Vitamin B Complex Deficiencies:

   • Thiamine (B1): Beriberi (neuropathy, heart failure).

   • Niacin (B3): Pellagra (diarrhea, dermatitis, dementia).

   • Folate (B9): Neural tube defects in fetuses, megaloblastic anemia.

B. Mineral Deficiencies

1. Iron Deficiency Anemia:

   • Symptoms: Fatigue, pallor, koilonychia (spoon nails).

   • Clinical Significance: Most common form of anemia worldwide.

   • Treatment: Iron-rich foods (red meat, lentils), supplementation.

2. Iodine Deficiency:

   • Symptoms: Goiter, hypothyroidism, cretinism in children.

   • Clinical Significance: Major cause of preventable mental retardation.

   • Treatment: Iodized salt and iodine supplements.

3. Zinc Deficiency:

   • Symptoms: Delayed wound healing, growth retardation, hypogonadism.

   • Clinical Significance: Affects immune function and growth in children.

   • Treatment: Zinc supplements and dietary sources (seafood, seeds).

3. Obesity and Overnutrition

Definition: Excess energy intake leading to accumulation of body fat.

• Clinical Features: High BMI (>30), hypertension, hyperlipidemia.

• Associated Conditions: Type 2 diabetes, cardiovascular diseases, fatty liver disease.

• Management:

  • Dietary modifications (reduce calories, increase fiber).

  • Physical activity and behavior therapy.

  • Pharmacotherapy or bariatric surgery in severe cases.

4. Metabolic Disorders

A. Diabetes Mellitus

Type 1: Autoimmune destruction of pancreatic β-cells.

Type 2: Insulin resistance due to overnutrition and obesity.

Clinical Significance: Long-term complications include neuropathy, nephropathy, and retinopathy.

Management: Lifestyle changes, insulin therapy, oral hypoglycemics.

B. Hyperlipidemia

Definition: Elevated cholesterol or triglycerides.

Clinical Significance: Increases the risk of atherosclerosis and cardiovascular diseases.

Management: Statins, a diet low in saturated fats.

5. Eating Disorders

A. Anorexia Nervosa

• Symptoms: Extreme weight loss, amenorrhea, lanugo hair.

• Clinical Significance: Can lead to multi-organ failure.

• Management: Nutritional rehabilitation, psychological therapy.

B. Bulimia Nervosa

• Symptoms: Binge eating followed by purging, and dental erosions.

• Clinical Significance: Electrolyte imbalances, and gastrointestinal damage.

• Management: Psychotherapy, nutritional counseling.

Clinical Significance of Nutritional Disorders

1. Economic Burden: Malnutrition increases healthcare costs and reduces productivity.

2. Global Health Impact: Nutritional disorders remain a leading cause of morbidity and mortality, especially in low- and middle-income countries.

3. Preventive Medicine: Understanding these disorders equips healthcare providers to implement effective preventive measures.

References for Further Reading

1. WHO. “Global Nutrition Report.”

2. FAO. “The State of Food Security and Nutrition in the World.”

3. Modern Nutrition in Health and Disease by Shils ME et al.

4. Harrison’s Principles of Internal Medicine, 21st Edition.