AIM Step 10
Student Memory Support
Topic 13 — Human Nutrition: Nutrients, Deficiency Disorders, Malnutrition and Obesity
4th Year MBBS • Endocrine + Reproduction • High-yield memory reinforcement and last-minute revision
1. High-Yield Flashcards
Tap each question to reveal the answer.
How are nutrients broadly classified?
Macronutrients and micronutrients.
Which three nutrients are the major energy-yielding macronutrients?
Carbohydrates, proteins and fats.
How much energy is provided by carbohydrate, protein and fat?
Carbohydrate 4 kcal/g, protein 4 kcal/g and fat 9 kcal/g.
What determines the quality of dietary protein?
Essential amino-acid composition and digestibility.
Which vitamins are fat-soluble?
Vitamins A, D, E and K.
Which deficiency causes night blindness and xerophthalmia?
Vitamin A deficiency.
Which vitamin deficiency causes rickets in children and osteomalacia in adults?
Vitamin D deficiency.
Which vitamin deficiency produces pellagra?
Niacin deficiency.
Which feature favors vitamin B12 deficiency over folate deficiency?
Neurological dysfunction.
Which mineral deficiency commonly causes microcytic hypochromic anemia?
Iron deficiency.
Which mineral deficiency is associated with goiter and impaired thyroid-hormone synthesis?
Iodine deficiency.
What does low weight-for-height indicate in a child?
Wasting, reflecting acute or recent undernutrition.
What does low height-for-age indicate?
Stunting, reflecting chronic undernutrition.
Which classical PEM syndrome shows severe wasting without nutritional edema?
Marasmus.
Which classical PEM syndrome is characterized by nutritional edema?
Kwashiorkor.
How is adult BMI calculated?
Weight in kilograms divided by height in metres squared.
2. Mnemonics
Mnemonic Title: Fat-Soluble Vitamins
ADEK
Meaning: Vitamins A, D, E and K are fat-soluble.
Mnemonic Title: Pellagra Features
3 Ds
Meaning: Dermatitis, diarrhea and dementia are the classic features of niacin deficiency.
Mnemonic Title: Child Nutrition Indicators
W-H-H
Meaning: Weight-for-age → underweight; weight-for-height → wasting; height-for-age → stunting.
3. Memory Tables
Marasmus vs Kwashiorkor
| Feature | Marasmus | Kwashiorkor |
|---|---|---|
| Main pattern | Severe total energy deficiency | Severe edematous malnutrition |
| Wasting | Marked | Present, may be masked |
| Edema | Absent | Present |
| Subcutaneous fat | Severely depleted | Relatively better preserved |
| Fatty liver | Not dominant | May occur |
Wasting vs Stunting
| Feature | Wasting | Stunting |
|---|---|---|
| Indicator | Low weight-for-height | Low height-for-age |
| Pattern | Acute/recent undernutrition | Chronic undernutrition |
| Main change | Loss of body mass | Impaired linear growth |
4. Rapid Revision Points — Last-Minute Revision
Must Remember:
- Balanced diet means adequate energy plus all essential nutrients in appropriate proportions.
- Fat is the most energy-dense macronutrient at about 9 kcal/g.
- Protein quality depends on essential amino acids and digestibility.
- Vitamin A deficiency affects vision and epithelial integrity.
- Vitamin C deficiency causes defective collagen formation and scurvy.
- Vitamin K deficiency causes bleeding due to impaired coagulation-protein activation.
- Iron deficiency limits hemoglobin synthesis and produces microcytic hypochromic anemia.
- Malnutrition and infection form a self-reinforcing cycle.
- Waterlow assessment separates wasting from stunting.
- BMI does not directly measure body fat or its distribution.
- Central adiposity is associated with greater metabolic risk.
- Obesity prevention depends on sustainable nutrition, physical activity and supportive environments.
Common KMU trap: Adequate calorie intake does not guarantee adequate nutrient quality; micronutrient or protein deficiency may still be present.
5. Clinical Memory Hooks
Difficulty seeing in dim light + dry conjunctiva → vitamin A deficiency
Bleeding gums + poor wound healing → vitamin C deficiency → defective collagen formation
Severe wasting without edema → marasmus
Severe malnutrition + bilateral edema → kwashiorkor
Obesity + snoring + daytime sleepiness → obstructive sleep apnea
6. Starred High-Yield Exam Points
- ⭐ Carbohydrate and protein provide about 4 kcal/g; fat provides about 9 kcal/g.
- ⭐ Vitamins A, D, E and K are fat-soluble and may become deficient in fat malabsorption.
- ⭐ Vitamin B12 deficiency can cause neurological dysfunction in addition to megaloblastic anemia.
- ⭐ Marasmus = severe wasting without edema; kwashiorkor = severe edematous malnutrition.
- ⭐ Low weight-for-height indicates wasting; low height-for-age indicates stunting.
- ⭐ Adult obesity begins at BMI 30 kg/m² or above, but BMI does not directly measure adiposity.
- ⭐ Sustained positive energy balance leads to adipose accumulation and obesity-related metabolic and mechanical complications.