Nutrition and Dietetics
Nutrition and dietetics tests nutritional assessment, deficiency diseases, therapeutic diets and community nutrition programmes. Items are often recognition-based: a clinical picture plus the missing nutrient.
Assessment
- BMI = weight (kg) ÷ height (m)². Under 18.5 is underweight, 18.5–22.9 normal for Asian Indians, 23–24.9 overweight, 25 and above obese.
- Mid-upper arm circumference below 13.5 cm in children aged 6–59 months indicates severe acute malnutrition.
- Gomez classification uses weight for age; the Wellcome classification uses weight for age plus oedema.
Deficiencies
- Vitamin A: night blindness, Bitot spots, xerophthalmia.
- Thiamine (B1): beriberi, Wernicke encephalopathy.
- Riboflavin (B2): angular stomatitis, cheilosis.
- Niacin (B3): pellagra with dermatitis, diarrhoea and dementia.
- Vitamin C: scurvy, bleeding gums, perifollicular haemorrhage.
- Vitamin D: rickets in children, osteomalacia in adults.
- Iron: microcytic hypochromic anaemia, koilonychia.
Worked example
A child of 12 kg and 90 cm has a BMI of 12 ÷ 0.81 = 14.8, far below the normal range for age, with bilateral pedal oedema and a moon face. This is kwashiorkor rather than marasmus: oedema and preserved subcutaneous fat are the discriminators, while marasmus shows severe wasting without oedema. Reasoning: the classification is clinical first, anthropometric second.
Therapeutic diets
Diabetic: high fibre, complex carbohydrate, no free sugar. Renal: low protein, low potassium, low phosphate, low sodium. Liver disease: low fat with frequent small feeds. Hypertension: DASH pattern with sodium under 2 g/day. Post-operative: clear liquids to full liquids to soft to normal.
Traps
Confusing marasmus with kwashiorkor, forgetting zinc for 14 days in diarrhoea, and mislabelling WHO low-osmolarity ORS (sodium 75, glucose 75, osmolarity 245) as the old high-osmolarity formula.