Nutrition

• (i) Cause:
- Kwashiorkor: Caused strictly by severe Protein deficiency, while calorie intake from carbohydrates may be adequate.
- Marasmus: Caused by severe, concurrent deficiency of BOTH Proteins and Calories (Carbohydrates)—general starvation.
• (ii) Age Group:
- Kwashiorkor: Typically affects children aged $1$ to $5\text{ years}$ (often after early weaning).
- Marasmus: Typically affects infants under $1\text{ year}$ of age.
• (iii) Presence of Oedema:
- Kwashiorkor: Oedema is present (pot-belly and swollen feet/face due to low plasma albumin protein osmotic imbalance).
- Marasmus: Oedema is completely absent; the child is emaciated to "skin and bones" with an "old man's face".

• Roughage: The indigestible fibrous carbohydrate matter (primarily cellulose) present in plant foods (whole grains, raw fruits, green leafy vegetables) that passes through the digestive system without being digested or absorbed.
• Two Vital Functions:
1. Stimulates Peristalsis: It adds non-digestible bulk to the food bolus, stimulating rhythmic muscular contractions (peristalsis) of the intestinal walls, ensuring smooth bowel movements and preventing constipation.
2. Adsorbs Toxins and Lowers Cholesterol: It binds to bile salts and toxic metabolic waste products in the colon, facilitating their rapid elimination and lowering blood cholesterol.

• (i) Scurvy: Vitamin C (Ascorbic Acid).
• (ii) Rickets: Vitamin D (Calciferol).
• (iii) Night Blindness: Vitamin A (Retinol).
• (iv) Beriberi: Vitamin B₁ (Thiamine).

• Fat-Soluble Vitamins: Vitamin A, Vitamin D, Vitamin E, Vitamin K (Remember mnemonic: K-E-D-A). These are absorbed with dietary lipids and stored in liver and adipose tissue.
• Water-Soluble Vitamins: Vitamin B-complex and Vitamin C. These cannot be stored in large quantities and must be supplied regularly in the daily diet (excess is excreted in urine).

• Importance: Iodine is an indispensable component required by the Thyroid Gland in the neck to synthesize the metabolic hormone Thyroxine ($T_4$). Thyroxine regulates the basal metabolic rate, physical growth, and mental development of the body.
• Deficiency Disease: Deficiency of iodine causes Simple Goitre (the thyroid gland enlarges abnormally to form a prominent swelling in the front of the neck in an attempt to capture trace iodine). Prevented by using iodized salt ($ ext{KIO}_3$).

• Deficiency Disease: Rickets.
• Deficient Vitamin: Vitamin D (Calciferol).
• Deficient Mineral: Calcium ($\text{Ca}$) (or Phosphorus).
• Mechanism: Vitamin D is required for the intestinal absorption of calcium. In its absence, growing bones fail to calcify properly, remaining soft and bending under the child's body weight.

• Standard physiological energy values:
- Carbohydrates: $4\text{ kcal/g}$
- Proteins: $4\text{ kcal/g}$
- Fats: $9\text{ kcal/g}$
• Calculation:
- From Carbohydrates $= 50 \times 4 = 200\text{ kcal}$
- From Proteins $= 20 \times 4 = 80\text{ kcal}$
- From Fats $= 10 \times 9 = 90\text{ kcal}$
• Total Energy:

$$\text{Total Energy} = 200 + 80 + 90 = \mathbf{370\text{ kcal}} \quad (\text{or } 370 \times 4.186 \approx \mathbf{1549\text{ kJ}})$$

• Iron is the central metallic atom in Hemoglobin, the iron-protein pigment in Red Blood Cells responsible for transporting oxygen from the lungs to all living cells.
• A deficiency of dietary iron causes Nutritional Anaemia (reduced hemoglobin concentration in blood).
• With less hemoglobin, blood transports inadequate oxygen to body tissues.
• The lack of cellular oxygen hampers aerobic cellular respiration in mitochondria, reducing ATP energy output, leading to chronic fatigue, paleness, and shortness of breath.