Vitamins Quiz: Basic Concepts

Water-Soluble Vitamins: B Vitamins and Vitamin C

• Water-soluble vitamins, including B vitamins and vitamin C, are organic and essential nutrients needed in small amounts for optimal health.
• These vitamins are necessary to prevent deficiency diseases.
• Early discovered vitamins contained nitrogen.

Chapter Outline

• The presentation outlines the water-soluble vitamins, encompassing B vitamins and vitamin C.
• It details the main roles, deficiency symptoms, recommendations, and food sources for each B vitamin individually.
• A similar breakdown is provided for vitamin C.

Vitamins - An Overview

• Vitamins are organic, essential nutrients required in small amounts to support optimal health.
• They help prevent deficiency diseases.
• Vitamins are not linked but are individual units.
• Vitamins do not yield energy when metabolized but assist enzymes for energy release from other nutrients like carbohydrates, fats, and proteins.
• Vitamin amounts are measured in micrograms or milligrams, not grams.
• Vitamins come from foods.

Structure, Function, and Food Contents of Vitamins

• Vitamins differ from carbohydrates, fats, and proteins regarding structure, and function.
• Vitamins are individual units not linked molecules of glucose or amino acids.
• They assist enzymes that release energy from carbohydrates, fats, and proteins.
• Intake requirements and amounts are measured in micrograms (mcg) or milligrams (mg).
• Vitamins come from food sources.

Classification of Vitamins

• Vitamins are categorized as water-soluble (B vitamins and vitamin C) and fat-soluble (vitamins A, D, E, and K).

Water-Soluble Vitamins: Absorption, Transport, Storage, Excretion, and Toxicity

• Water-soluble vitamins are absorbed directly into the bloodstream.
• They circulate freely in the body's water-filled compartments.
• Kidneys eliminate any excess from the body through urine.
• They are less likely to reach harmful levels from dietary intake.
• Toxicity is more likely to occur from taking supplements.
• They typically need to be taken frequently (e.g., 1-3 days).

B Vitamins

• The presentation details specific vitamins under B vitamins, such as Thiamin, Riboflavin, Niacin, Biotin, Pantothenic acid, Vitamin B6, Folate, Vitamin B12, and Choline.

Thiamin (Vitamin B1)

• Thiamin pyrophosphate (TPP), the biologically active form, is formed by transferring a pyrophosphate group from ATP to thiamin.
• Important in energy metabolism and occupies a special site on nerve cell membranes.
• Good sources include whole-grain, fortified, or enriched grain products.
• Deficiency symptoms include a form of beriberi.
• Recommended intakes are Men: 1.2 mg/d and Women: 1.1 mg/d.

Riboflavin (Vitamin B2)

• The two active forms are flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
• Serves as a coenzyme in many reactions, notably in energy metabolism.
• Good sources include milk and milk products
• Deficiency can cause inflammation in the membranes of mouth, skin, eyes, and GI tract.

Niacin (Vitamin B3)

• The active forms are nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+).
• Critical in energy transfer reactions.
• NAD and NADP are central in glucose and fat metabolism.
• Niacin protects against neurological degeneration.
• Obtained from Milk, eggs, meat, poultry, fish; whole-grains, fortified and enriched grain products; nuts.
• Intakes: Men: 16 mg NE/d and Women: 14 mg NE/d.
• Deficiency symptoms include pellagra.
• Excess intake is generally nontoxic.

Biotin

• Biotin functions in metabolism as a coenzyme carrying activated carbon dioxide.
• It participates in gluconeogenesis, fatty acid synthesis, and fatty acid breakdown.
• Sources are widespread in foods, including egg yolks, liver, fish, and whole grains.
• Deficiency is rare. No toxicity is reported.

Pantothenic Acid (Vitamin B5)

• Pantothenic acid is part of coenzyme A, which forms acetyl-CoA.
• Involved in lipid synthesis, synthesis of neurotransmitters, steroid hormones, and hemoglobin.
• Widespread in foods: beef, poultry, whole grains, potatoes, tomatoes, and broccoli.
• Deficiency is rare. No toxicity is reported.

Vitamin B6

• The active forms are pyridoxal, pyridoxine, and pyridoxamine, which can become the PLP (pyridoxal phosphate) enzyme.
• PLP is involved in more than 100 reactions, including carbohydrate and amino acid metabolism.
• PLP is involved in converting tryptophan to niacin and neurotransmitter serotonin.
• PLP participates in heme, nucleic acid, and lecithin synthesis.
• Sources include meats, fish, poultry, potatoes, legumes, fortified cereals, and liver.
• Deficiency can cause depression and confusion. Toxicity can result in neurological damage.

Folate (Folic Acid)

• Folate's active form is tetrahydrofolate (THF), a crucial coenzyme.
• THF receives one-carbon fragments and transfers them to amino acid synthesis intermediates.
• Required for the synthesis of DNA needed for rapidly growing cells.
• Regenerates the amino acid methionine from homocysteine.
• Sources include fortified grains, leafy green vegetables, legumes, seeds, and liver.
• Deficiency causes macrocytic or megaloblastic anemia.
• Toxicity symptoms are related to masking B12 deficiency.

Vitamin B12 (Cobalamin)

• Physiologically active coenzymes are 5'-deoxyadenosylcobalamin and methylcobalamin.
• B12's function depends on several steps in digestion and absorption.
• Essential for the regeneration of the amino acid methionine, the synthesis of DNA and RNA.
• Involved in maintaining the sheaths that surround and protect nerve fibers.

Choline

• Choline is an essential nutrient and is often categorized with B vitamins.
• It's involved in neurotransmitter acetylcholine and phospholipid lecithin synthesis.
• Good sources include milk, liver, eggs, and peanuts.
• Deficiency symptoms include liver damage.
• Toxicity symptoms include low blood pressure.

Vitamin C (Ascorbic Acid)

• Its main function is as a reducing agent in various reactions.
• Acts as an antioxidant, protecting against oxidative damage.
• Important in collagen formation.
• Helps the body withstand infections.
• Aids in iron absorption.
• Sources include citrus fruits, dark green vegetables, strawberries, tomatoes, and mangoes.
• Deficiency causes scurvy.

Test your knowledge on vitamins with this quiz that covers their classifications, roles, and distinctions between water-soluble and fat-soluble types. Discover what makes vitamins unique compared to other nutrients and enhance your understanding of daily intake measurements.