Retinol Quiz: Vitamin A Overview and Study Guide

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Questions and Answers

What is the classification of Vitamin A (Retinol)?

Water-soluble

Protein-soluble

Carbohydrate-soluble

Fat-soluble (correct)

Which vitamin is essential for normal metabolism among the following?

Vitamin B1 (Thiamine) (correct)

Vitamin A (Retinol)

Vitamin K

Vitamin B2 (Riboflavin)

What type of vitamin is Vitamin B2 (Riboflavin)?

Fat-soluble

Carbohydrate-soluble

Protein-soluble

Water-soluble (correct)

Which vitamin can be stored in the body for a long time?

Vitamin A (Retinol) Signup and view all the answers

Which vitamin deficiency can lead to a specific deficiency disease?

Vitamin B2 (Riboflavin) Signup and view all the answers

What happens when the chemical structure of a vitamin is destroyed?

Its function is lost Signup and view all the answers

Which vitamin cannot be produced by the body and must be obtained through the diet?

Vitamin A (Retinol) Signup and view all the answers

What is the unique characteristic of fat-soluble vitamins in terms of absorption and storage?

Absorbed with lipids and stored for a long time Signup and view all the answers

What happens to water-soluble vitamins after absorption in the body?

Remain in the body for a short time before being excreted Signup and view all the answers

Which vitamin is known for its role in nerve function and energy metabolism?

Vitamin B1 (Thiamine) Signup and view all the answers

What is the classification of Vitamin B2 (Riboflavin) based on its solubility?

Water-soluble vitamin Signup and view all the answers

Why is it important to consume a variety of foods to obtain essential vitamins?

No single food item provides all essential vitamins Signup and view all the answers

Which vitamin is essential for vision, immune function, and skin health?

Vitamin A (Retinol) Signup and view all the answers

What happens if overcooked food containing vitamins is consumed regularly?

Destruction of vitamin chemical structure leading to loss of function Signup and view all the answers

Which type of vitamins cannot be broken down by catabolism and are used in their original forms by the body?

Fat-soluble vitamins Signup and view all the answers

Which vitamin can be produced by intestinal bacteria within the body?

Vitamin K Signup and view all the answers

What is the primary role of Vitamin B2 (Riboflavin) in the body?

Maintenance of healthy red blood cells Signup and view all the answers

Study Notes

Classification of Vitamins

Vitamins can be classified into two categories:
- Fat-soluble vitamins: can be absorbed from the intestine along with lipids, can be stored in the body for a long time, and can accumulate in the body to the point of toxicity
- Water-soluble vitamins: absorbed with water from the intestinal tract, typically remain in the body only a short time before being excreted in the urine

Essential Vitamins

Cannot be produced by the body
Must be obtained through the diet
No single food item or nutrient class provides all the essential vitamins
Absence of essential vitamins in the diet can lead to specific deficiency diseases

Vitamins

Vitamin A (Retinol):
- Fat-soluble
- RDI: 900
- Sources: provitamin, carotene, liver, egg yolk, butter, and milk
- Function: necessary for rhodopsin synthesis, normal health of epithelial cells, and bone and tooth growth
- Deficiency symptoms: rhodopsin deficiency, night blindness, retarded growth, skin disorders, and increased infection risk
Vitamin B1 (Thiamine):
- Water-soluble
- RDI: 1.2 mg
- Sources: yeast, grains, and milk
- Function: involved in carbohydrate and amino acid metabolism, necessary for growth
- Deficiency symptoms: beriberi, muscle weakness, neuritis, and paralysis
Vitamin B2 (Riboflavin):
- Water-soluble
- RDI: 1.3 mg
- Sources: green vegetables, liver, wheat germ, milk, and eggs
- Function: component of flavin adenine, dinucleotide, involved in citric acid cycle
- Deficiency symptoms: eye disorders and skin crackling, especially at corners of the mouth
Pantothenic acid:
- Water-soluble
- RDI: 16 mg
- Sources: liver, yeast, green vegetables, grains, and intestinal bacteria
- Function: constituent of coenzyme-A, glucose production from lipids and amino acids, steroid hormone synthesis
- Deficiency symptoms: neuromuscular dysfunction and fatigue
Biotin:
- Water-soluble
- RDI: 30 μg
- Sources: liver, yeast, eggs, and intestinal bacteria
- Function: fatty acid and nucleic acid synthesis, movement of pyruvic acid into citric acid cycle
- Deficiency symptoms: mental and muscle dysfunction, fatigue, and nausea
Vitamin B6 (Pyridoxine):
- Water-soluble
- RDI: 17 mg
- Sources: fish, liver, yeast, tomatoes, and intestinal bacteria
- Function: involved in amino acid metabolism
- Deficiency symptoms: dermatitis, retarded growth, and nausea
Folate:
- Water-soluble
- RDI: 0.4 mg
- Sources: liver, green leafy vegetables, and intestinal bacteria
- Function: nucleic acid synthesis, hematopoiesis, prevents birth defects
- Deficiency symptoms: macrocytic anemia, spina bifida
Vitamin B12 (Cobalamins):
- Water-soluble
- RDI: 2.4 μg
- Sources: liver, red meat, milk, and eggs
- Function: necessary for red blood cell production, some nucleic acid and amino acid metabolism
- Deficiency symptoms: pernicious anemia, nervous system disorders
Vitamin C (Ascorbic acid):
- Water-soluble
- RDI: 90 mg
- Sources: citrus fruit, tomatoes, and green vegetables
- Function: collagen synthesis, general protein metabolism
- Deficiency symptoms: scurvy, defective bone formation, poor wound healing
Vitamin D (Cholecalciferol, Ergosterol):
- Fat-soluble
- RDI: 10 μg
- Sources: fish liver oil, enriched milk, and eggs, provitamin D converted by sunlight to cholecalciferol in the skin
- Function: promotes calcium and phosphorus use, normal growth, and bone and tooth formation
- Deficiency symptoms: rickets, poorly developed weak bones, osteomalacia, bone reabsorption
Vitamin E (Tocopherol, Tocotrienols):
- Fat-soluble
- RDI: 15 mg
- Sources: wheat germ, cottonseed, palm, and rice oils, grain, liver, and lettuce
- Function: prevents oxidation of cell membranes and DNA
- Deficiency symptoms: hemolysis of red blood cells
Vitamin K (Phylloquinone):
- Fat-soluble
- RDI: 120 μg
- Sources: alfalfa, liver, spinach, vegetable oils, cabbage, and intestinal bacteria
- Function: required for synthesis of a number of clotting factors
- Deficiency symptoms: excessive bleeding due to retarded blood clotting

Provitamins and Coenzymes

Provitamins: parts of a vitamin that the body can assemble or modify into a functional vitamin
- Examples: beta carotene, 7-dehydrocholesterol, tryptophan
Coenzymes: combine with enzymes to make the enzymes functional
- Examples: vitamins B2, B3, biotin, and pantothenic acid, folate, and Vitamin B12

History of Vitamins

First identified at the beginning of the 20th century
Found to be associated with certain foods that were known to protect people from diseases such as rickets and beriberi
1941: The first Food and Nutrition Board established the Recommended Dietary Allowances (RDAs)

Recommended Dietary Allowances (RDAs)

Nutrient intakes that are sufficient to meet the needs of nearly all people in certain age and gender groups
Established for different-aged males and females, starting with infants and continuing on to adults
Also set for pregnant and lactating women
RDAs have been reevaluated every 4-5 years and updated, when necessary, on the basis of new information

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Explore the essential information about Vitamin A (Retinol) including its sources, functions, and symptoms of deficiency. Test your knowledge on the principal vitamins and their roles in maintaining overall health.