Introduction to Nutrition and Dietetics
What this domain tests
Nutrition is the science of nutrients, their action, interaction and balance in health and disease. Dietetics is the application of that science to feeding individuals or groups, including therapeutic diets. The exam tests definitions, the nutrient classification, forms of malnutrition and the difference between food, diet, nutrient and dietetics.
Core rules
- Nutrients are chemical substances needed for growth, maintenance and reproduction; they are divided into macronutrients (carbohydrate, protein, fat) and micronutrients (vitamins, minerals), with water treated separately.
- Food supplies energy and nutrients; a diet is the pattern of foods eaten; dietetics is the professional application of nutrition.
- Malnutrition covers undernutrition (stunting, wasting, underweight, micronutrient deficiency) and overnutrition (overweight and obesity).
- A dietitian assesses, plans, implements and monitors nutrition care; the focus is on the person and the disease, not merely on the food.
Worked example
A two-year-old presents with bilateral pitting oedema, poor growth, low serum albumin and a diet of dilute rice water. Reasoning: oedema with low albumin and poor growth points to kwashiorkor-type protein-energy malnutrition, not marasmus, which shows severe wasting without oedema. The answer is not simply “give more rice”; it requires energy-dense therapeutic feeds, micronutrients, infection treatment and gradual refeeding to avoid refeeding syndrome.
Traps that cost marks
- Calling every thin child malnourished without measuring weight, height and diet.
- Confusing marasmus (severe wasting) with kwashiorkor (oedema, low albumin).
- Defining “diet” only as a weight-loss diet; in this subject it means any planned pattern of eating.
- Writing “nutritionist” and “dietitian” as exact synonyms without noting the clinical role of the dietitian.