Vitamins: Functions and Daily Requirements
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Questions and Answers

Which vitamin is classified as fat-soluble and is also acknowledged for its potential toxicity?

  • Vitamin B12
  • Vitamin C
  • Vitamin A (correct)
  • Folic Acid

What is the primary reason some water-soluble vitamins are less toxic than fat-soluble vitamins?

  • They are more fragile and easily destroyed.
  • Excess amounts are excreted by the body. (correct)
  • They are less important for body function.
  • They are absorbed in the fat tissues.

Which vitamin is stored in significant amounts within the liver and can maintain a person without intake for several months?

  • Vitamin D
  • Vitamin C
  • Vitamin B6
  • Vitamin A (correct)

Which of the following is true about the storage of most water-soluble vitamins?

<p>They lack storage and are excreted quickly. (B)</p> Signup and view all the answers

Which vitamin can cause symptoms of deficiency within a few weeks and potentially lead to death from scurvy in a few months?

<p>Vitamin C (C)</p> Signup and view all the answers

Beta-carotene is categorized as which type of vitamin component?

<p>A precursor or provitamin. (C)</p> Signup and view all the answers

What distinguishes vitamins from macronutrients in terms of caloric contribution?

<p>Vitamins do not provide any calories. (C)</p> Signup and view all the answers

Which of the following vitamins has a significant storage time of 2 to 4 months in the body?

<p>Vitamin D (D)</p> Signup and view all the answers

What primary symptom results from severe thiamine deficiency due to weakened cardiac muscle?

<p>Cardiac failure (B)</p> Signup and view all the answers

Which condition is commonly associated with niacin deficiency that includes symptoms like diarrhea and dermatitis?

<p>Pellagra (A)</p> Signup and view all the answers

What physiological change occurs due to thiamine deficiency that affects blood return to the heart?

<p>Increased venous return (B)</p> Signup and view all the answers

Which vitamin deficiency can lead to muscle weakness and poor glandular secretion?

<p>Niacin (B)</p> Signup and view all the answers

What is a common gastrointestinal symptom due to severe thiamine deficiency?

<p>Severe constipation (C)</p> Signup and view all the answers

Which vitamin is primarily synthesized from the amino acid tryptophan?

<p>Niacin (A)</p> Signup and view all the answers

Which enzyme is formed by riboflavin combining with phosphoric acid?

<p>FAD (D)</p> Signup and view all the answers

What consequence does a diet high in corn have on niacin absorption?

<p>Exacerbation of pellagra (A)</p> Signup and view all the answers

What is the primary metabolic role of pantothenic acid (Vitamin B5) in the body?

<p>Conversion of pyruvic acid into acetyl-CoA (C)</p> Signup and view all the answers

What effect does ascorbic acid deficiency have on the body?

<p>Weakening of collagen fibers (A)</p> Signup and view all the answers

What condition is primarily caused by vitamin D deficiency in children?

<p>Rickets (C)</p> Signup and view all the answers

Which of the following is NOT a function of vitamin D?

<p>Regulates blood sugar levels (C)</p> Signup and view all the answers

What is a likely consequence of long-term ascorbic acid deficiency?

<p>Increased fracture risk (B)</p> Signup and view all the answers

Which of the following describes a key symptom of scurvy?

<p>Petechial hemorrhages (A)</p> Signup and view all the answers

How does vitamin D specifically aid in the formation of a calcium binding protein?

<p>Activating intestinal epithelial cells (D)</p> Signup and view all the answers

What is a negative effect of inadequate vitamin D regarding bone health?

<p>Prevents calcium absorption (C)</p> Signup and view all the answers

What is one of the key functions of Vitamin A in the body?

<p>Formation of retinal pigments in the eye (A)</p> Signup and view all the answers

What does a deficiency of Vitamin A contribute to in terms of epithelial tissue?

<p>Stratification and keratinization (D)</p> Signup and view all the answers

How does thiamine (Vitamin B1) primarily function in the metabolism of carbohydrates?

<p>As a coenzyme in decarboxylation reactions (C)</p> Signup and view all the answers

Which of the following conditions is associated with thiamine deficiency?

<p>Beriberi (C)</p> Signup and view all the answers

What is a consequence of thiamine deficiency on neuronal tissue?

<p>Decreased glucose utilization (A)</p> Signup and view all the answers

Vitamin A is often referred to as an 'anti-infection' vitamin because it helps prevent infections in which of the following systems?

<p>Epithelial structures like conjunctivae and respiratory passages (D)</p> Signup and view all the answers

Which symptom is NOT associated with Vitamin A deficiency?

<p>Bone fragmentation (A)</p> Signup and view all the answers

Thiamine deficiency leads to lesions in which part of the human body?

<p>Central and peripheral nervous systems (D)</p> Signup and view all the answers

What is one of the main symptoms of severe riboflavin deficiency?

<p>Depression of oxidative processes (A)</p> Signup and view all the answers

Which of the following roles is attributed to vitamin B12?

<p>Coenzyme in cell synthesis (C)</p> Signup and view all the answers

What condition is primarily caused by a deficiency of intrinsic factor?

<p>Pernicious anemia (A)</p> Signup and view all the answers

Which of the following is a significant consequence of folic acid deficiency?

<p>Macrocytic anemia (A)</p> Signup and view all the answers

Which tissue specific process does vitamin B6 primarily aid in?

<p>Transamination for amino acid synthesis (A)</p> Signup and view all the answers

What effect is caused by riboflavin deficiency?

<p>Dermatitis and nausea (B)</p> Signup and view all the answers

Which of the following statements about vitamin B12 is FALSE?

<p>It directly influences iron metabolism. (A)</p> Signup and view all the answers

What is the primary nutritional implication of vitamin B6 deficiency?

<p>Neurological disturbances and seizures (A)</p> Signup and view all the answers

Flashcards

Daily Requirements of Vitamins

Essential nutrients needed for normal body function, growth, and maintenance of tissues, but do not provide energy. Needed in small amounts (mg or mcg).

Fat-Soluble Vitamins

Vitamins A, D, E, and K. Absorbed with fat, stored in the liver and fat tissue. Toxicity is a concern, particularly with A and D.

Water-Soluble Vitamins

Vitamins C and the B vitamins. Stored minimally (except B12), and excess is usually excreted. Sensitive to heat, light, and alkaline conditions.

Vitamin A's Active Forms

Retinol, retinal, retinoic acid have crucial roles in the body.

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Vitamin A Precursors

Beta-carotene (and other carotenoids) serve as the source for making vitamin A in the body.

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Vitamin Storage (Fat-Soluble)

Fat-soluble vitamins are stored in the liver and fat tissues for later use.

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Vitamin Storage (Water-Soluble)

Water-soluble vitamins are not stored extensively; excess is excreted from body.

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Vitamin B12 Storage

B12 is an exception to water-soluble vitamins, storing to a slightly larger extent, taking longer to show symptoms of deficiency.

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Vitamin A deficiency symptoms

Skin problems (acne), stunted growth, reproductive issues (infertility in males and females), and vision problems (corneal opacity and blindness).

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Vitamin A's role in the body

Formation of retinal pigments in the eye, contributes to vision, and supports cell (especially epithelial cell) growth.

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Vitamin A function

Essential for preventing night blindness (vision issue) and the health of epithelial tissues.

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Carotenoids and Vitamin A

Dietary carotenoid pigments (yellow and red ones) can be converted into vitamin A in the liver.

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Thiamine (Vitamin B1) function

Acts as a coenzyme (cocarboxylase) for carbohydrate and amino acid metabolism.

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Thiamine deficiency (Beriberi)

Reduced glucose use by nerve tissue, increased fat use, and nervous system damage (polyneuritis).

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Thiamine deficiency effects

Causes nerve damage, paralysis, and muscle weakness, affecting central and peripheral nervous systems.

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Thiamine and glucose utilization

In thiamine deficiency, glucose utilization by nerve tissue may decrease significantly.

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Thiamine Deficiency Effect on the Heart

Severe thiamine deficiency weakens the heart muscle, leading to cardiac failure. It also causes peripheral vasodilation due to decreased energy production in tissues, resulting in dilated blood vessels.

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Thiamine Deficiency and Blood Return

Thiamine deficiency causes a significant increase in venous blood return to the heart, often doubling the normal amount.

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Thiamine Deficiency and Gastrointestinal Issues

Thiamine deficiency leads to digestive problems like indigestion, severe constipation, loss of appetite, weak stomach muscles, and low stomach acid production.

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Beriberi

Beriberi is the umbrella term for a collection of symptoms caused by thiamine deficiency, including nerve damage, heart problems, and digestive issues.

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What are NAD and NADP?

NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) are coenzymes essential for hydrogen transfer in cellular processes. They are derived from niacin (vitamin B3).

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Niacin Deficiency Impact

Niacin deficiency disrupts energy transfer from food to cells, causing various symptoms like muscle weakness, poor gland function, and digestive problems.

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Pellagra

Pellagra is a condition caused mainly by niacin deficiency, characterized by diarrhea, dermatitis, dementia, and potentially death.

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Why Corn and Pellagra?

Corn is deficient in tryptophan, an amino acid that the body can convert into niacin. This makes people on a corn-based diet more susceptible to pellagra.

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Riboflavin Deficiency

A lack of riboflavin can cause similar effects to niacin deficiency, due to impaired cellular oxidative processes.

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Riboflavin Deficiency Symptoms

Mild riboflavin deficiency can lead to digestive problems, burning sensations in skin and eyes, cracked mouth corners, headaches, mental decline, and forgetfulness.

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Vitamin B12's Function

Vitamin B12, containing cobalt, acts as a coenzyme for cell synthesis, works with folate for RBC production, maintains nerve cells, and prevents nerve damage.

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Vitamin B12 Deficiency Cause

Vitamin B12 deficiency is usually not caused by lack of the vitamin in food, but by the lack of intrinsic factor, essential for its absorption.

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Pernicious Anemia

Anemia caused by the failure of red blood cell maturation, resulting from vitamin B12 deficiency.

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Folic Acid Function

Folic acid (vitamin B9) carries hydroxymethyl and formyl groups, crucial for purine and thymine synthesis, needed for DNA formation and cell replication.

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Folic Acid Deficiency

Folic acid deficiency can lead to macrocytic anemia, which means red blood cells are abnormally large.

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Pyridoxine (Vitamin B6) Function

Pyridoxine exists as pyridoxal phosphate and acts as a coenzyme in amino acid synthesis, and helps transport some amino acids.

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Pantothenic Acid (Vitamin B5)

A vitamin that plays a crucial role in energy production by being incorporated into coenzyme A (CoA). CoA is involved in converting pyruvate to acetyl-CoA for the citric acid cycle and breaking down fatty acids.

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Coenzyme A (CoA)

A vital cofactor that works with various enzymes in the body. It's particularly important in breaking down carbohydrates and fats to generate energy.

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Ascorbic Acid (Vitamin C)

This essential vitamin is crucial for making collagen, a protein that provides structure and support to connective tissues, like skin, bones, and cartilage.

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Collagen

A fibrous protein found in connective tissues. It helps provide structure, strength, and elasticity to these tissues.

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Scurvy

A disease caused by vitamin C deficiency. It weakens connective tissues, leading to symptoms like delayed wound healing, fragile blood vessels, and bleeding gums.

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Vitamin D

This 'sunshine' vitamin plays a crucial role in calcium absorption from the gut and helps regulate its deposition in bones. It also promotes phosphate absorption and reduces calcium and phosphate excretion from the body.

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Rickets

A disease affecting children caused by vitamin D deficiency. It weakens bones due to inadequate calcium and phosphate absorption, leading to bone deformities.

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Calcium Binding Protein

A protein in intestinal cells that helps bind calcium for better absorption. Formation of this protein is stimulated by vitamin D.

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Study Notes

Physiological Functions of Vitamins

  • Vitamins are essential for normal body functioning, growth, and maintenance of tissues.
  • Vitamins are needed in very small amounts.
  • Milligrams (mg) are 1/1000 of a gram.
  • Micrograms (mcg) are 1/1,000,000 of a gram.
  • Lack of vitamins can cause metabolic deficiencies.
  • Daily requirements vary based on body size, growth rate, exercise, and pregnancy.

Daily Requirements

  • Vitamins are not a source of energy.
  • Specific amounts are needed for proper body function.
  • Different vitamins have different required daily amounts.

Vitamin Amounts

  • Vitamin A: 5000 IU
  • Thiamine: 1.5 mg
  • Riboflavin: 1.8 mg
  • Niacin: 20 mg
  • Ascorbic acid: 45 mg
  • Vitamin D: 400 IU
  • Vitamin E: 15 IU
  • Vitamin K: 70 µg - (micrograms)
  • Folic acid: 0.4 mg
  • Vitamin B12: 3 µg
  • Pyridoxine: 2 mg
  • Pantothenic acid: Unknown amount

Major Roles of Vitamins

  • Antioxidants: protect cells from damage (Vitamin E, C)
  • Coenzymes: assist in chemical reactions (8 B vitamins)
  • Vision: crucial for vision (Vitamin A)
  • Bone health: essential for strong bones (Vitamin D)
  • Blood clotting: necessary for blood clotting (Vitamin K),
  • Cellular growth: necessary for growth of most cells (Vitamin A)

Types of Vitamins

  • Fat-soluble vitamins: Vitamins A, D, E, and K.
    • Absorbed with dietary fat
    • Stored in liver and fatty tissue
    • Toxicity more likely, especially excess Vitamin A and D
  • Water-soluble vitamins: Vitamins C and the 8 B complex vitamins.
    • Little stored (except B12) in the body
    • Less toxic if excess is consumed.
    • Sensitive to heat, light, and alkaline conditions during cooking.

Vitamin Storage

  • Vitamins are stored to some degree in all cells, but some vitamins are stored more significantly in the liver.
  • Vitamin A: stored for 5-10 months.
  • Vitamin D: stored for 2-4 months.
  • Water-soluble vitamins have less storage.

Vitamin A

  • Active forms include retinol, retinal, and retinoic acid.
  • Beta-carotene is a precursor (provitamin)
  • Beta-carotene produces two molecules of vitamin A when absorbed.
  • Found in animal tissues (retinol) and plant foods (provitamins) as carotenoids (yellow & red pigments).
  • Essential for vision, cell growth and other body functions.

Vitamin A Deficiency

  • Results in visual problems (night blindness).
  • Can affect growth of cells and tissues.
  • Epithelial cells (lining of organs and body surfaces) are affected.
  • Skin may become stratified and keratinized.
  • Can impact skin and eyes.

Other Vitamins

  • Thiamine (B1): coenzyme for carbohydrate metabolism; deficiency causes beriberi (various symptoms).
  • Niacin (B3): coenzyme; deficiency causes pellagra (symptoms like skin problems, dementia, and diarrhea)
  • Riboflavin (B2): coenzyme in oxidative processes; deficiency can mimic niacin deficiency.
  • Vitamin B12: coenzyme for cell synthesis, folate absorption, and nerve function; deficiency can cause pernicious anemia and nerve damage.
  • Folic acid (B9): critical for DNA synthesis and red blood cell production; deficiency causes macrocytic anemia, and impacts growth.
  • Pyridoxine (B6): involved in amino acid metabolism; deficiency causes neurological problems.
  • Pantothenic acid (B5): part of coenzyme A, fundamental to metabolic pathways; deficiency symptoms not well documented.
  • Ascorbic acid (Vitamin C): essential for collagen synthesis, wound healing, and immune function; deficiency causes scurvy.
  • Vitamin D: regulates calcium and phosphate levels.
  • Vitamin E: antioxidant; deficiency rare but can affect fertility and cause muscle and nerve problems.
  • Vitamin K: important in blood clotting; deficiency rare.

Vitamin Deficiencies

  • Specific diseases (and symptoms) can occur when a person does not have enough of a particular vitamin.
  • Examples of deficiencies: -Rickets (Vitamin D) -Scurvy (Vitamin C) -Pellagra (Niacin) -Beriberi (thiamine)

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Description

This quiz covers the essential physiological functions of vitamins and their daily requirements for proper body functioning. It explores the unique roles each vitamin plays, the consequences of deficiencies, and the specific daily amounts needed for optimal health.

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