Assignment 5

 

## SAQ

### 1. Define a balanced diet. Discuss protein-energy malnutrition with the nutritional importance of proteins.

**Balanced Diet:**

A balanced diet provides all essential nutrients in the right proportions to maintain health, growth, and proper body function. It typically includes:

- Carbohydrates: for energy.

- Proteins: for growth, repair, and enzyme production.

- Fats: for energy, cell function, and absorption of vitamins.

- Vitamins and minerals: for various biochemical functions.

- Water: for hydration and physiological processes.

- Fiber: for digestive health.

**Protein-Energy Malnutrition (PEM):**

PEM occurs when there is a deficiency of proteins and calories in the diet. It is prevalent in developing countries, particularly among children. PEM manifests in two major forms:

- **Kwashiorkor:** Characterized by edema, an enlarged liver, skin lesions, and hair changes. It results from protein deficiency with adequate caloric intake.

- **Marasmus:** Characterized by severe weight loss, muscle wasting, and depletion of fat stores. It results from both protein and caloric deficiency.

**Nutritional Importance of Proteins:**

Proteins are crucial for:

- Building and repairing tissues, including muscles and organs.

- Producing enzymes and hormones.

- Supporting immune function.

- Maintaining fluid and pH balance.

- Providing energy when carbohydrate and fat intake are insufficient.

### 2. Write a note on beneficial and adverse effects of dietary fibers in nutrition.

**Beneficial Effects of Dietary Fibers:**

- **Digestive Health:** Fiber helps prevent constipation by adding bulk to stool and promoting regular bowel movements.

- **Blood Sugar Control:** Soluble fiber slows glucose absorption, helping manage blood sugar levels.

- **Cholesterol Reduction:** Soluble fiber binds with cholesterol in the intestines, reducing its absorption and lowering blood cholesterol levels.

- **Weight Management:** High-fiber foods are filling, which can help control appetite and reduce calorie intake.

- **Reduced Risk of Diseases:** Adequate fiber intake is associated with a lower risk of cardiovascular diseases, type 2 diabetes, and colorectal cancer.

**Adverse Effects of Dietary Fibers:**

- **Gastrointestinal Discomfort:** Excessive fiber intake can cause bloating, gas, and cramps.

- **Interference with Nutrient Absorption:** High fiber levels can bind with minerals like calcium, iron, and zinc, reducing their absorption.

- **Intestinal Obstruction:** Extremely high fiber intake, especially without adequate water, can lead to intestinal blockages in rare cases.

### 3. Explain the role of various blood buffers in the maintenance of blood pH.

Blood buffers maintain blood pH (7.35-7.45) by neutralizing excess acids or bases. The major blood buffers include:

- **Bicarbonate Buffer System:** The primary buffer in blood. It consists of bicarbonate ions (HCO₃⁻) and carbonic acid (H₂CO₃). When pH drops (acidic), HCO₃⁻ neutralizes excess H⁺ ions. When pH rises (basic), H₂CO₃ dissociates to release H⁺ ions.

- **Hemoglobin Buffer System:** Hemoglobin in red blood cells can bind to H⁺ ions, helping to buffer the blood.

- **Phosphate Buffer System:** Consists of dihydrogen phosphate (H₂PO₄⁻) and hydrogen phosphate (HPO₄²⁻). It operates mainly in intracellular fluid and renal tubular fluid.

- **Protein Buffer System:** Proteins contain amino acid residues that can accept or donate H⁺ ions, acting as buffers in both intracellular and extracellular fluids.

### 4. Define antioxidants. Name antioxidant enzymes, vitamins, and minerals.

**Antioxidants:**

Antioxidants are substances that protect cells from damage caused by free radicals, which are unstable molecules that can cause oxidative stress, leading to cellular damage and contributing to various diseases.

**Antioxidant Enzymes:**

- Superoxide Dismutase (SOD)

- Catalase

- Glutathione Peroxidase

**Antioxidant Vitamins:**

- Vitamin C (ascorbic acid)

- Vitamin E (tocopherol)

- Vitamin A (retinoids and carotenoids)

**Antioxidant Minerals:**

- Selenium

- Zinc

- Copper

- Manganese

## LAQ

### 1. Describe sources, biochemical function, RDA, and deficiency manifestations of calcium.

**Sources of Calcium:**

- Dairy products: milk, cheese, yogurt.

- Leafy green vegetables: broccoli, kale.

- Fortified foods: orange juice, cereals.

- Nuts and seeds: almonds, sesame seeds.

- Fish with bones: sardines, salmon.

**Biochemical Function of Calcium:**

- Structural component of bones and teeth.

- Involved in muscle contraction.

- Plays a role in blood clotting.

- Necessary for nerve transmission.

- Functions in intracellular signaling and enzyme activation.

**Recommended Dietary Allowance (RDA):**

- Infants: 200-260 mg/day

- Children (1-8 years): 700-1,000 mg/day

- Adolescents (9-18 years): 1,300 mg/day

- Adults (19-50 years): 1,000 mg/day

- Older adults (51+ years): 1,200 mg/day

- Pregnant and lactating women: 1,000-1,300 mg/day

**Deficiency Manifestations of Calcium:**

- **Hypocalcemia:** Low blood calcium levels leading to muscle spasms, cramps, and convulsions.

- **Osteoporosis:** Weak and brittle bones, increasing fracture risk, common in older adults.

- **Rickets:** Soft and weak bones in children, causing skeletal deformities.

- **Osteomalacia:** Softening of bones in adults, leading to bone pain and muscle weakness.

### 2. Explain the absorption, regulation, functions, and deficiency manifestations of iron.

**Absorption of Iron:**

- **Heme Iron:** Found in animal products, easily absorbed in the small intestine.

- **Non-Heme Iron:** Found in plant sources, absorption is influenced by other dietary factors (enhanced by vitamin C, inhibited by phytates, polyphenols).

**Regulation of Iron:**

- **Hepcidin:** A liver-produced hormone that regulates iron absorption and release. High hepcidin levels inhibit iron absorption and release from stores.

- **Iron Storage:** Ferritin stores iron in the liver, spleen, and bone marrow. 

- **Transport:** Transferrin binds and transports iron in the bloodstream.

**Functions of Iron:**

- Component of hemoglobin in red blood cells, essential for oxygen transport.

- Part of myoglobin, facilitating oxygen use in muscles.

- Required for various enzymatic reactions and cellular respiration.

- Involved in DNA synthesis and repair.

**Deficiency Manifestations of Iron:**

- **Iron Deficiency Anemia:** Characterized by fatigue, weakness, pale skin, and shortness of breath due to reduced oxygen-carrying capacity.

- **Pica:** Craving for non-nutritive substances like ice or dirt.

- **Restless Legs Syndrome:** Uncomfortable leg sensations, often relieved by movement.

- **Impaired Cognitive and Immune Function:** Particularly in children, leading to developmental delays and increased susceptibility to infections.

By understanding these detailed aspects, individuals can make informed decisions about their diet and nutritional health.