Vitamins and Their Functions

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Questions and Answers

What distinguishes vitamins from carbohydrates, fats, and proteins in terms of structure?

Vitamins are linked together as molecules.

Vitamins are not essential nutrients.

Vitamins are individual units and not linked. (correct)

Vitamins provide energy when metabolized.

Why are vitamins measured in micrograms or milligrams?

Vitamins can only be obtained through supplements.

Vitamins have no role in enzyme function.

Vitamins are required in small amounts. (correct)

Vitamins yield energy when metabolized.

Which statement is true regarding the solubility of vitamins?

Water-soluble vitamins include B vitamins and vitamin C. (correct)

Fat-soluble vitamins are only found in animal products.

Fat-soluble vitamins are typically less essential.

All vitamins are water-soluble.

What is one role of vitamins in the body?

Vitamins assist enzymes in energy release. Signup and view all the answers

Which classification includes vitamin C?

Water-soluble vitamins Signup and view all the answers

How do vitamins differ from energy-yielding nutrients?

Vitamins do not yield energy when metabolized. Signup and view all the answers

What is a common characteristic of all vitamins?

They are essential and organic nutrients. Signup and view all the answers

What is one of the main roles of pantothenic acid in the body?

Formation of acetyl CoA Signup and view all the answers

Which of the following foods is particularly high in pantothenic acid?

Potatoes Signup and view all the answers

What is the adequate intake (AI) recommendation for adults concerning pantothenic acid?

5 mg/d Signup and view all the answers

What important function does pyridoxal phosphate (PLP) serve in the body?

Facilitates over 100 metabolic reactions Signup and view all the answers

Which of the following symptoms is NOT associated with pantothenic acid deficiency?

Deficiency symptoms are rare Signup and view all the answers

What is the upper limit (UL) of niacin intake for adults?

35 mg/d Signup and view all the answers

Which of the following symptoms is associated with niacin deficiency?

Diarrhea Signup and view all the answers

Which of the following food items is a known source of biotin?

Egg yolks Signup and view all the answers

What is the recommended dietary allowance (AI) of biotin for adults?

30 µg/d Signup and view all the answers

What condition may arise due to niacin toxicity?

Niacin flush Signup and view all the answers

Which metabolic pathways does pantothenic acid (Vitamin B5) primarily affect through coenzyme A?

TCA cycle Signup and view all the answers

What characterizes a biotin deficiency?

Rare occurrence Signup and view all the answers

What is one of the roles of biotin in the body?

Carrying activated carbon dioxide Signup and view all the answers

Which disease is associated with severe niacin deficiency?

Pellagra Signup and view all the answers

Which of the following is NOT a role of biotin in metabolism?

Electrolyte balance Signup and view all the answers

What is the biologically active form of riboflavin that is NOT mentioned in the provided content?

Riboflavin diphosphate (RDP) Signup and view all the answers

Which of the following symptoms is associated with riboflavin deficiency?

Inflammation of the mouth membranes Signup and view all the answers

What is the major dietary source of riboflavin for most people?

Milk and milk products Signup and view all the answers

Which enzyme is known to protect against neurological degeneration?

Nicotinamide adenine dinucleotide (NAD) Signup and view all the answers

Which vitamin's recommendation is expressed in niacin equivalents (NE)?

Niacin (Vitamin B3) Signup and view all the answers

What is the recommended dietary allowance (RDA) for men regarding riboflavin?

1.3 mg/d Signup and view all the answers

Approximately how much tryptophan is needed to produce 1 mg of niacin?

60 mg Signup and view all the answers

Which of the following is NOT a rich source of niacin?

Dairy products Signup and view all the answers

What is the primary adverse effect associated with an excess of thiamin?

None reported Signup and view all the answers

Which of the following statements about riboflavin is correct?

Riboflavin serves mainly as a coenzyme in energy metabolism. Signup and view all the answers

What is the biologically active form of thiamin?

Thiamin pyrophosphate Signup and view all the answers

Which of the following is a symptom of dry beriberi caused by thiamin deficiency?

Muscle weakness Signup and view all the answers

Which food source is particularly rich in thiamin?

Whole-grain products Signup and view all the answers

What is the primary role of thiamin in the body?

Assisting energy metabolism Signup and view all the answers

What is the recommended daily intake of thiamin for adult women?

1.1 mg/d Signup and view all the answers

Which of the following represents a consequence of prolonged thiamin deficiency?

Beriberi Signup and view all the answers

Which condition is associated with wet beriberi?

Edema and cardiovascular issues Signup and view all the answers

What is a common risk factor for thiamin deficiency?

Over-reliance on empty-calorie foods Signup and view all the answers

What specific site in the body does thiamin occupy that is crucial for its function?

Membrane of nerve cells Signup and view all the answers

Study Notes

Water-Soluble Vitamins: B Vitamins and Vitamin C

Vitamins are organic, essential nutrients needed in small amounts for optimal health.
They contain nitrogen, first discovered in vitamins.
These vitamins differ from carbohydrates, fats, and proteins because they are individual units without a chain structure.
Water-soluble vitamins are easily absorbed and travel freely in the body. Excess is removed through the kidneys, but they can still reach harmful levels in high intake from supplements.
They are needed in frequent doses.

Chapter Outline

Overview of vitamins
Main roles, deficiency symptoms, and food sources for each B vitamin.
Main roles, deficiency symptoms, and food sources for vitamin C.

The Vitamins – an Overview

Vitamins are essential organic nutrients required by the body in small quantities to prevent deficiency diseases and maintain optimal health.
Vitamin B, C, and other vitamins play roles in energy metabolism from carbohydrates, fats, and proteins

Structure, Function, and Food Content of Vitamins

Vitamins are individual units that act in assisting metabolic enzymes to release stored energy in carbohydrates, fats, and proteins.
Vitamins are measured in micrograms or milligrams vs. carbohydrates fats and proteins in grams.

Classification of Vitamins

Vitamins are classified as water-soluble or fat-soluble.
Water-soluble vitamins include B vitamins and vitamin C.
Fat-soluble vitamins include vitamins A, D, E, and K.

The B Vitamins

The B vitamins are a group of water-soluble vitamins that play crucial roles in various metabolic functions.
Individual B vitamins include thiamin (B1), riboflavin (B2), niacin (B3), biotin (B7), pantothenic acid (B5), pyridoxine (B6), and cobalamin (B12), and choline.
The B vitamins function as coenzymes, assisting enzymes in energy release and other metabolic processes.

Thiamin (Vitamin B1)

Thiamin pyrophosphate (TPP) is the biologically active form of thiamin.
It participates in energy metabolism.
Important for nerve cells.
Dietary sources: whole-grain, fortified, or enriched grain products.

Riboflavin (Vitamin B2)

The active forms are flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
Riboflavin acts as a coenzyme in many metabolic reactions.
Dietary sources include milk, and milk products.

Niacin (Vitamin B3)

The active coenzymes are nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+).
Essential in energy transfer, and glucose and fat metabolism.
Protects against neurological degeneration.
Dietary sources include milk, eggs, meat, poultry, fish, whole grains, fortified and enriched grain products.

Biotin

Biotin plays an important role in metabolism as a coenzyme to carry activated carbon dioxide.
It participates in gluconeogenesis, fatty acid synthesis, and the breakdown of certain fatty acids and amino acids.
Dietary sources include egg yolks, liver, fish, and whole grains.

Pantothenic Acid (Vitamin B5)

Pantothenic acid is a part of coenzyme A (CoA).
Involved in the formation of acetyl CoA for energy metabolism and in the synthesis of lipids, neurotransmitters, steroid hormones, and hemoglobin.
Dietary sources include widespread in foods; beef, poultry, whole grains, potatoes, tomatoes and broccoli

Vitamin B6

The active coenzyme form is pyridoxal phosphate (PLP).
Active in more than 100 enzymatic reactions, including carbohydrate and amino acid metabolism.
Converts tryptophan to niacin and serotonin.
Synthesis of heme, nucleic acid and lecithin.

Folate (Folic Acid)

Folic acid forms tetrahydrofolate (THF), a reduced coenzyme.
It receives one-carbon fragments from donors, and transfers them to intermediates.
Necessary for the synthesis of amino acids, DNA, and other crucial molecules.

Vitamin B12 (Cobalamin)

Two active coenzyme forms are 5'deoxyadenosylcobalamin and methylcobalamin.
Critical for DNA synthesis, and amino acid metabolism.
Essential in the production of neurotransmitters, and bone growth.

Choline

Choline is an essential nutrient in the B vitamin group, often used in the synthesis of neurotransmitters and phospholipids.

Vitamin C (Ascorbic Acid)

It acts as a reducing agent in metabolic processes.
Supports collagen synthesis, and strengthens resistance to infection.
An antioxidant.

###Recommendations& Food Sources, in summary

Recommendations for each vitamin depend on gender and other conditions such as smoking.
Food sources are varied, and some are better sources of specific vitamins
Some foods are good sources of multiple vitamins.

Deficiency and Toxicity Symptoms, in summary

Deficiency symptoms and toxicity vary per vitamin.
Always seek professional medical guidance when symptoms appear, whether they be deficiencies or toxicity from supplements.

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Description

This quiz explores the distinctions between vitamins and macronutrients such as carbohydrates, fats, and proteins. It examines the properties, roles, and dietary requirements of various vitamins, including vitamin C, pantothenic acid, and niacin. Learn about their solubility, food sources, and deficiencies to enhance your understanding of nutrition.