Vitamins Quiz: C, B9, and B1 Insights

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following vitamins is also known as ascorbic acid?

Vitamin C (correct)

Vitamin E

Vitamin B9

Vitamin B1

What is the recommended dietary allowance (RDA) of vitamin C for adult women?

100 mg/day

90 mg/day

60 mg/day

75 mg/day (correct)

What condition is primarily associated with a deficiency of vitamin C?

Beriberi

Microcytic anemia

Night blindness

Scurvy (correct)

Vitamin B9 is crucial for the biosynthesis of which of the following compounds?

DNA Signup and view all the answers

Which of the following symptoms is NOT associated with vitamin C deficiency?

Fractured bones Signup and view all the answers

What is the primary role of vitamin C in relation to connective tissue?

Maintaining normal collagen production Signup and view all the answers

Which vitamin is considered to be a coenzyme for the conversion of carbohydrates into energy?

Vitamin B2 Signup and view all the answers

Which of the following populations is most likely to experience a deficiency in folic acid (Vitamin B9)?

Pregnant women Signup and view all the answers

What is the primary function of Thiamine (Vitamin B1) in the body?

Energy metabolism of carbohydrates Signup and view all the answers

What is the RDA of Niacin (Vitamin B3) for males?

16 mg NE/day Signup and view all the answers

Which of the following conditions is characterized by the 'four Ds' associated with Niacin deficiency?

Pellagra Signup and view all the answers

Which vitamin is found in its biologically active forms as FMN and FAD?

Riboflavin (Vitamin B2) Signup and view all the answers

What is the result of Thiamine deficiency in the body?

Decreased ATP production Signup and view all the answers

Which food sources are high in Niacin (Vitamin B3)?

Poultry and fish Signup and view all the answers

What is a common characteristic of Riboflavin (Vitamin B2) deficiency?

Ariboflavinosis Signup and view all the answers

Which form of Niacin can be synthesized in the body from the dietary amino acid tryptophan?

Nicotinamide Signup and view all the answers

What is a possible consequence of folate deficiency during pregnancy?

Increased risk of neural tube defects Signup and view all the answers

Which nutrient is primarily responsible for re-methylation of homocysteine to methionine?

Vitamin B12 Signup and view all the answers

What condition arises from impaired DNA synthesis due to folate and vitamin B12 deficiencies?

Megaloblastic anemia Signup and view all the answers

What is the Recommended Dietary Allowance (RDA) for vitamin B12?

2.4 μg/day Signup and view all the answers

What dietary sources are rich in vitamin B12?

Food from animal origin Signup and view all the answers

What can excessive supplementation of folic acid lead to?

Increased risk of cancer Signup and view all the answers

Which nutrient deficiency can result in elevated levels of homocysteine?

Folate Signup and view all the answers

What physiological process requires both N5, N10-methylene and N10-formyl forms of THF?

DNA replication Signup and view all the answers

What is the recommended daily allowance (RDA) of Pantothenic acid for adults?

5 mg/day Signup and view all the answers

Which of the following is NOT a function of Pyridoxal phosphate (Vitamin B6)?

Formation of acetyl CoA Signup and view all the answers

Which vitamin has a known toxicity that can lead to neurotoxic effects?

Vitamin B6 Signup and view all the answers

What might cause a Vitamin B6 deficiency in patients undergoing treatment?

Isoniazid usage Signup and view all the answers

What is the primary source of Biotin (Vitamin B7)?

Gut normal flora Signup and view all the answers

What condition can result from a deficiency of Pantothenic acid?

Vomiting and hypoglycemia Signup and view all the answers

Which of the following vitamins is primarily sourced from animal products?

Pyridoxal Signup and view all the answers

Which symptom is commonly associated with Biotin deficiency?

Depression and hallucinations Signup and view all the answers

Study Notes

Vitamins II: Water Soluble Vitamins

Learning Objectives: Identify water-soluble vitamins, state their functions, understand associated deficiencies, and enumerate their clinical indications.

Classification

Water-Soluble Vitamins:
- Non-B complex: Ascorbic acid (vitamin C)
- B Complex:
  - Energy releasing: Thiamine (vitamin B₁), Riboflavin (vitamin B₂), Niacin (vitamin B₃), Pantothenic acid (vitamin B₅), Biotin (vitamin B₇)
  - Hematopoietic: Riboflavin (vitamin B₂), Niacin (vitamin B₃), Pantothenic acid (vitamin B₅), Pyridoxine (vitamin B₆), Folate (vitamin B₉), Cobalamin (vitamin B₁₂)
  - Other: Pyridoxine (vitamin B₆), Folate (vitamin B₉), Cobalamin (vitamin B₁₂)
Fat-Soluble Vitamins:
- Vitamin A (retinol, β-carotenes)
- Vitamin D (cholecalciferol)
- Vitamin K (phylloquinones, menaquinones)
- Vitamin E (tocopherols)

Vitamin C (Ascorbic Acid)

Naturally Present: In some foods, added to others, and as a dietary supplement.
Essential Dietary Component: Humans cannot synthesize vitamin C endogenously.
Recommended Dietary Allowance (RDA): 90 mg/day for adult men, 75 mg/day for adult women.
Functions:
- Reducing agent (antioxidant)
- Regeneration of vitamin E
- Maintenance of connective tissue and wound healing (collagen).
- Coenzyme in hydroxylation reactions.
Deficiency:
- Scurvy (sore and spongy gums, loss of teeth, fragile blood vessels, poor wound healing, frequent infections).
- Microcytic anemia

Folic Acid (Vitamin B9)

Sources: Leafy and dark green vegetables.
Role in Metabolism: Key role in one-carbon metabolism (methyl, methylene, methenyl, formyl, or formimino) for DNA, polyamines, amino acids, creatine, and phospholipids synthesis.
Deficiency: Likely the most common vitamin deficiency in the United States (particularly in pregnant women and those with alcoholism),
Consequences: Megaloblastic anemia, Neural tube defects (supplementation recommended before conception and during the first trimester).
Toxicity Issues: High-dose supplementation may be associated with an increased risk of cancer

Vitamin B12 (Cobalamin)

RDA: 2.4 µg/day.
Sources: Food from animal origin (liver, red meat, eggs, dairy products, fortified cereals).
Synthesis: Synthesized only by microorganisms, not by plants.
Function: Re-methylation of homocysteine to methionine, which requires N5-methyl THF. Deficiency results in elevated homocysteine levels.
Deficiency: Pronounced in rapidly dividing cells (bone marrow and intestinal mucosal cells); megaloblastic anemia
Clinical Significance: Related to neural tube defects.

Thiamine (Vitamin B1)

Active Form: Thiamine pyrophosphate (TPP).
Activation: Activated by transferring a pyrophosphate group from adenosine triphosphate (ATP).
Coenzyme Role: Serves as a coenzyme in the oxidative decarboxylation of α-keto acids (important in Krebs' cycle)
Energy Metabolism: Essential for energy metabolism (especially in the central nervous system).
Deficiency: Decreased ATP production and impaired cellular function.

Riboflavin (Vitamin B2)

Active Forms: Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
Coenzyme Role: Tightly bound to flavoenzymes that catalyze oxidation or reduction of a substrate. Critically important for energy production.
Stability: Stable to heat, but water-soluble, thus lost during food processing.
RDA: Males 1.3 mg/day, Females 1.1 mg/day.
Deficiency (Ariboflavinosis): Inflammation of membranes (mouth, skin, eyes, and GI tract)

Niacin (Vitamin B3)

Alternative Names: Nicotinic acid or nicotinamide.
Conversion: Nicotinamide in the diet can be converted into nicotinic acid in the body.
Tryptophan Precursor: Dietary tryptophan is a precursor (1% of dietary protein).
Active Forms: NAD (nicotinamide adenine dinucleotide) and NADP.
RDA: Males 16 mg NE/day, Females 14 mg NE/day.
Function: Important for metabolic reactions (Krebs' cycle).
Deficiency (Pellagra): Diarrhea, dermatitis, dementia, and death (the "four Ds"). Primary pellagra from malnutrition (lack of niacin or tryptophan), secondary from impaired niacin absorption.

Pantothenic Acid (Vitamin B5)

Adequate Intake: 5 mg/day for adults.
Active Form: Coenzyme A (CoA).
Function: Essential for energy metabolism, formation of acetyl CoA (Krebs' cycle), fatty acid synthesis, cholesterol synthesis, and ketone body synthesis.
Sources: Moderate amounts in all nutrients; destroyed by food processing.
Deficiency: Rare but can cause vomiting, hypoglycemia, and cramps.

Pyridoxal (Vitamin B6)

Collective Term: Includes pyridoxine, pyridoxal, and pyridoxamine.
Sources: Pyridoxine mainly in plants; pyridoxal and pyridoxamine primarily in animal foods.
Active Form: Pyridoxal phosphate (PLP), serves as a coenzyme for many reactions involving amino acids (transamination, deamination, decarboxylation, condensation).
RDA: 1.3 mg/day for adults
Clinical Indications: Isoniazid use may lead to B6 deficiency. Therefore, dietary supplementation with B6 is often given as an adjunct to this treatment.
Toxicity: Pyridoxine is the only water-soluble vitamin with significant toxicity, causing neurotoxicity (depression, fatigue, irritability, headaches, nerve damage, muscle weakness).

Biotin (Vitamin B7/H)

RDA: 30 µg/day for adults.
Enzyme Role: Coenzyme for decarboxylase enzyme in the TCA (Krebs' cycle) and gluconeogenesis
Sources: Moderate amounts in most foods. Gut normal flora can produce biotin.
Deficiency: rare but may cause depression, lethargy, or hair loss.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on essential vitamins, including Vitamin C (ascorbic acid), B9 (Folic Acid), and B1 (Thiamine). This quiz covers recommended dietary allowances, deficiency symptoms, and primary functions of these vital nutrients. See how well you understand the importance of these vitamins in health.