Chapter 11

Question 1

Characteristics of Fat-Soluble Vitamins

Answer 1

Require bile for digestion and absorption.
Transported via the lymphatic system.
Excess stored in liver and adipose tissues.
Not readily excreted, increasing toxicity risk.

Question 2

Forms in the Body

Vitamin A and Beta-Carotene

Answer 2

Retinol: Supports reproduction; major transport and storage form.
Retinal: Active in vision.
Retinoic Acid: Regulates cell differentiation, growth, and embryonic development.

Question 3

Sources

Vitamin A and Beta-Carotene

Answer 3

Animal: Preformed vitamin A (retinoids).
Plant: Beta-carotene (provitamin A, antioxidant).

Question 4

Functions

Vitamin A and Beta-Carotene

Answer 4

Vision: Maintains clear cornea, converts light into nerve impulses via rhodopsin.
Cell Differentiation: Maintains epithelial and goblet cells for mucous production.
Reproduction & Growth: Sperm development, fetal development, bone remodeling.

Question 5

Deficiency

Vitamin A and Beta-Carotene

Answer 5

Night blindness and xerophthalmia (blindness).
Impaired immune function, keratinization of skin and epithelial cells.
Increases risk of infection and worsens malnutrition.

Question 6

Toxicity

Vitamin A and Beta-Carotene

Answer 6

UL exceeded by preformed vitamin A (animal sources, supplements).
Symptoms: Cell damage, weakened bones, birth defects, and no benefit for acne treatment.
Beta-carotene toxicity manifests as yellow skin (non-toxic).

Question 7

Recommendations

Vitamin A and Beta-Carotene

Answer 7

Measured in Retinol Activity Equivalents (RAE) or International Units (IU).

Question 8

Synthesis

Vitamin D

Answer 8

Non-essential; synthesized from cholesterol with sunlight exposure.
Activated in liver and kidneys.

Question 9

Functions

Vitamin D

Answer 9

Maintains blood calcium and phosphorus levels for bone health.
Protects against cognitive decline in nerve cells.

Question 10

Sources

Vitamin D

Answer 10

Limited in food: Oily fish, egg yolks, fortified milk, beef.
Sun exposure needed for adequate synthesis.

Question 11

Deficiency

Vitamin D

Answer 11

Risk factors: Dark skin, elderly, lack of sunlight, breastfeeding without supplementation.
Diseases:

Rickets: Bone deformities in children.
Osteomalacia: Soft bones in adults.
Osteoporosis: Increased fracture risk.

Question 12

Toxicity

Vitamin D

Answer 12

From supplements, not sunlight.
Symptoms: Hypercalcemia, kidney stones, hardened blood vessels (can be fatal).

Question 13

Forms

Vitamin E

Answer 13

Tocopherols and tocotrienols (alpha-tocopherol most active).

Question 14

Functions

Vitamin E

Answer 14

Antioxidant: Protects cells, prevents LDL oxidation (heart disease).

Question 15

Sources

Vitamin E

Answer 15

Vegetable oils, seeds, nuts, fresh foods.

Question 16

Deficiency

Vitamin E

Answer 16

Rare; secondary causes include fat malabsorption (e.g., cystic fibrosis).
Symptoms: Erythrocyte hemolysis (anemia), neuromuscular dysfunction.

Question 17

Toxicity

Vitamin E

Answer 17

Rare; extremely high doses can interfere with Vitamin K (blood clotting), causing hemorrhaging.

Question 18

Functions

Vitamin K

Answer 18

Blood clotting: Activates proteins like prothrombin.
Bone metabolism: Activates osteocalcin for mineral binding.

Question 19

Sources

Vitamin K

Answer 19

Non-food: Synthesized by gut bacteria.
Food: Leafy greens (kale, spinach), vegetable oils, fruits (avocado, kiwi).

Question 20

Deficiency

Vitamin K

Answer 20

Primary: Rare due to adequate dietary intake.
Secondary:

Antibiotics kill gut bacteria.
Fat malabsorption due to bile production failure.

Infants: Sterile gut at birth; require vitamin K injection.

Question 21

Toxicity

Vitamin K

Answer 21

Rare; no UL established.
High doses interfere with anticoagulant drugs.

Question 22

Summary of Deficiency Diseases

Answer 22

Vitamin A: Night blindness, xerophthalmia, keratinization.
Vitamin D: Rickets, osteomalacia, osteoporosis.
Vitamin E: Hemolytic anemia, neuromuscular dysfunction.
Vitamin K: Impaired clotting, low bone density.