Vitamins: Basic Concepts

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Questions and Answers

What is the primary reason why all vitamins have been discovered?

All vitamins have been discovered because they were found to be essential nutrients that prevent deficiency diseases.

What is the key characteristic that defines a vitamin?

A vitamin is an organic compound that is required in small amounts for normal growth, development, and metabolism, but cannot be synthesized by the human body.

What is the main difference between fat-soluble and water-soluble vitamins?

Fat-soluble vitamins (A, D, E, and K) can accumulate in the body and cause toxicity, whereas water-soluble vitamins (B and C) are generally excreted and do not build up to toxic levels.

What are some ways to conserve the vitamin content of foods?

<p>Ways to conserve vitamin content include reducing cooking time and water usage, storing foods properly, and using cooking methods that minimize vitamin destruction.</p> Signup and view all the answers

What is the primary function of antioxidants in the body?

<p>Antioxidants protect cells from damage caused by free radicals, which are unstable molecules that can cause oxidative stress and contribute to chronic diseases.</p> Signup and view all the answers

What is the purpose of vitamin enrichment and fortification?

<p>Vitamin enrichment and fortification involve adding vitamins to foods to restore nutrients lost during processing and to prevent deficiency diseases.</p> Signup and view all the answers

What was the significance of James Lind's experiment in 1753?

<p>James Lind's experiment demonstrated that citrus fruits could cure scurvy, leading to the discovery of vitamin C.</p> Signup and view all the answers

What were the typical signs and symptoms of scurvy experienced by sailors during lengthy ocean voyages?

<p>Signs and symptoms of scurvy included fatigue, petechiae, skin bruising, gum swelling and bleeding, tooth loss, slow healing of wounds, and irritability.</p> Signup and view all the answers

Why were British sailors nicknamed 'limeys'?

<p>Because they consumed citrus fruits, including lemons, to prevent scurvy, and people often referred to citrus fruits as 'limes' during that time.</p> Signup and view all the answers

What was James Lind's understanding of scurvy when he administered citrus fruits to sailors?

<p>He thought scurvy was a digestive system disorder that could be treated with substances associated with warm climates.</p> Signup and view all the answers

What is the origin of the term 'vitamine'?

<p>It was coined by Casimir Funk, who discovered a substance in rice bran that he thought would cure beriberi, combining 'vita' (necessary for life) and 'amine' (a type of nitrogen-containing substance).</p> Signup and view all the answers

Why is it unlikely that any vitamin still needs to be discovered?

<p>Because babies grow and thrive on infant formulas, and very ill people can be kept alive for years on liquid synthetic feedings containing all known nutrients, including vitamins.</p> Signup and view all the answers

What percentage of a slice of bread's weight is composed of vitamins?

<p>About 0.005% (1.48 mg)</p> Signup and view all the answers

What is the primary function of vitamins in the human body?

<p>Regulating a variety of body processes, including those involved in cell division and development, as well as the growth and maintenance of tissues.</p> Signup and view all the answers

What are the four criteria that define a vitamin?

<p>The body cannot synthesize the compound or make enough to maintain good health; the compound naturally occurs in commonly eaten foods; signs and symptoms of a health problem occur when the substance is missing from the diet; and good health is restored when the deficiency disorder is treated early by supplying the missing substance.</p> Signup and view all the answers

What is the difference between a vitamin and a provitamin?

<p>A vitamin is the active form that functions in the body, whereas a provitamin is a precursor that needs to be converted into the active form.</p> Signup and view all the answers

What is the main difference between the amounts of vitamins and macronutrients required by the body?

<p>The body requires vitamins in milligram or microgram amounts, but it needs grams of macronutrients.</p> Signup and view all the answers

What are International Units (IUs) used to express?

<p>Amounts of certain vitamins, although their use is being replaced by more precise measures.</p> Signup and view all the answers

What is an oxidation reaction, and what is its consequence if left uncontrolled?

<p>An oxidation reaction is when an atom or molecule loses one or more electrons, and if left uncontrolled, it can lead to a chain reaction causing excessive oxidation and damaging cells.</p> Signup and view all the answers

How many functions do vitamins generally have?

<p>More than one</p> Signup and view all the answers

What is the role of antioxidants in the body?

<p>Antioxidants protect cells by giving up electrons to radicals, thereby preventing oxidation and damage to molecules such as polyunsaturated fatty acids and DNA.</p> Signup and view all the answers

What is choline classified as?

<p>A vitamin-like essential nutrient</p> Signup and view all the answers

What are some natural sources of vitamins?

<p>Plants, animals, fungi, and even bacteria supply natural forms of vitamins in our diets.</p> Signup and view all the answers

How do vitamins participate in releasing energy from glucose, fatty acids, and amino acids?

<p>Vitamins participate in the chemical reactions that release energy from these macronutrients, but they are not a direct source of energy.</p> Signup and view all the answers

What is a radical, and how does it affect molecules?

<p>A radical is a highly reactive substance with an unpaired electron that removes electrons from more stable molecules, causing damage or destruction.</p> Signup and view all the answers

What is the benefit of some radical formation in the body?

<p>Some radical formation is necessary and provides benefits, such as stimulating normal cell growth and division, and helping white blood cells destroy infectious agents.</p> Signup and view all the answers

What is the difference between a vitamin's function and its role in energy metabolism?

<p>Vitamins regulate various bodily functions, but they do not directly provide energy; instead, they participate in the chemical reactions that release energy from macronutrients.</p> Signup and view all the answers

How do antioxidants, like vitamin E, protect cells from radicals?

<p>Antioxidants, like vitamin E, protect cells by giving up electrons to radicals, forming a more stable structure and preventing oxidation and damage to molecules.</p> Signup and view all the answers

What is the difference in biological activity between natural and synthetic vitamin E?

<p>Natural vitamin E has more biological activity than synthetic vitamin E.</p> Signup and view all the answers

Which vitamin has almost twice the biological activity in its synthetic form compared to its natural form?

<p>Folic acid</p> Signup and view all the answers

What percentage of adults reported regular use of a multivitamin/mineral supplement according to the 2011–2012 National Health and Examination Survey?

<p>31%</p> Signup and view all the answers

Why is it not necessary to consume 100% of every vitamin each day?

<p>Because cells contain a supply of vitamins that can last for several days and possibly even years, and bacteria in the lower intestinal tract produce certain vitamins.</p> Signup and view all the answers

What vitamins are added to refined wheat flour and certain other milled grain products as part of the federally regulated grain enrichment program?

<p>Thiamin, riboflavin, niacin, and folic acid</p> Signup and view all the answers

What is the purpose of grain enrichment and fortification?

<p>To improve vitamin intakes of Americans and protect against deficiency diseases.</p> Signup and view all the answers

What type of vitamins are vitamins A, D, E, and K?

<p>Fat-soluble vitamins</p> Signup and view all the answers

Why are nutrition experts concerned about the addition of vitamins to foods and beverages?

<p>They are concerned that it may lead to excessive intake of a few vitamins while reducing intake of others.</p> Signup and view all the answers

What type of bacteria and algae are used to produce vitamins for supplement production?

<p>Certain types of bacteria and algae</p> Signup and view all the answers

Which vitamins are often added to milk as part of the fortification process?

<p>Vitamins A and D</p> Signup and view all the answers

What is the significance of the body's ability to eliminate excess water-soluble vitamins?

<p>The body's ability to eliminate excess water-soluble vitamins helps prevent toxicity, as these vitamins are not stored in the body and can be filtered out by the kidneys and eliminated in urine.</p> Signup and view all the answers

What facilitates the absorption of fat-soluble vitamins in the small intestine?

<p>The presence of fat in the small intestine, which stimulates the secretion of a hormone that causes the gallbladder to release bile, facilitating the absorption of fat-soluble vitamins.</p> Signup and view all the answers

What is the consequence of diseases or conditions that affect the GI tract on vitamin absorption?

<p>Diseases or conditions that affect the GI tract can reduce vitamin absorption, leading to deficiencies of these micronutrients.</p> Signup and view all the answers

Why may people with fat malabsorption disorders need to take large oral doses of vitamin supplements?

<p>To enable small amounts of the vitamins to be absorbed, as their bodies are unable to absorb vitamins efficiently due to fat malabsorption.</p> Signup and view all the answers

What is the benefit of consuming a diet that includes minimally processed fruits, vegetables, and whole-grain breads and cereals?

<p>Such a diet can help supply the vitamin needs of most healthy people.</p> Signup and view all the answers

Why is it important to add a small amount of fat to low-fat foods?

<p>To enhance the absorption of fat-soluble vitamins in these foods.</p> Signup and view all the answers

What is the significance of vitamin B-12 being an exception to limited storage of water-soluble vitamins?

<p>Vitamin B-12 can be stored in the body for extended periods, making it an exception to the general rule that the body stores only limited amounts of most water-soluble vitamins.</p> Signup and view all the answers

How can reduced vitamin absorption lead to deficiencies of micronutrients?

<p>Reduced vitamin absorption can lead to deficiencies of micronutrients because the body may not be able to obtain adequate amounts of essential vitamins from the diet.</p> Signup and view all the answers

What is the consequence of accumulating excess fat-soluble vitamins in the body?

<p>Accumulating excess fat-soluble vitamins in the body can lead to toxicity, especially with vitamins A and D.</p> Signup and view all the answers

Why is it important to understand the classification of vitamins as fat-soluble or water-soluble?

<p>Understanding the classification of vitamins as fat-soluble or water-soluble is important because it determines how the body absorbs, stores, and eliminates these micronutrients.</p> Signup and view all the answers

What is the purpose of blanching vegetables before freezing, and how can it be stopped to avoid overcooking?

<p>Blanching denatures plant enzymes that cause deterioration. It can be stopped by plunging the produce into cold water.</p> Signup and view all the answers

What are some characteristics of fresh produce that you should avoid when selecting fruits and vegetables?

<p>Bruised, wilted, shriveled, or decaying produce, or those with mold.</p> Signup and view all the answers

How can you minimize vitamin loss when storing fresh fruits and vegetables?

<p>Store at temperatures near freezing, in high humidity, and away from air.</p> Signup and view all the answers

Why is it recommended to trim, peel, and cut raw fruits and vegetables just before eating or serving?

<p>To reduce exposure to heat, alkaline substances, light, and air that can destroy vitamins.</p> Signup and view all the answers

What is the benefit of cooking vegetables in small amounts of water and reusing the cooking water?

<p>Retains water-soluble vitamins that would otherwise be lost in the cooking water.</p> Signup and view all the answers

Why is it recommended to cook fruits and vegetables in their skins when possible?

<p>To conserve vitamins and nutrients found in the skin.</p> Signup and view all the answers

What are the primary factors that determine a plant's vitamin content?

<p>Genetic makeup, growing conditions (including soil composition and sunlight exposure), and maturity at harvest.</p> Signup and view all the answers

Why are older adults more likely to develop vitamin deficiency disorders?

<p>Older adults are at higher risk due to factors such as reduced intestinal absorption, higher excretion of vitamins, and other age-related health issues.</p> Signup and view all the answers

What is the advantages of quick cooking methods like microwaving, steaming, and stir-frying in conserving vitamins?

<p>They cook quickly, use minimal water, and reduce exposure to heat, water, and air.</p> Signup and view all the answers

How does microwave cooking compare to conventional cooking methods in terms of nutrient retention?

<p>It does not reduce nutrient content more than conventional cooking methods.</p> Signup and view all the answers

What is the likely outcome if a person consistently consumes a diet lacking a particular vitamin?

<p>Depletion of the vitamin's body stores, followed by the onset of deficiency disease symptoms.</p> Signup and view all the answers

What is the purpose of steaming vegetables, and how is it done?

<p>To conserve vitamins; done by placing vegetables in a steamer basket over boiling water.</p> Signup and view all the answers

Why is it unnecessary to worry about vitamin toxicity disorders in healthy adults taking multivitamin supplements?

<p>Multivitamins usually contain less than two times the Daily Values of each micronutrient, making toxicity unlikely.</p> Signup and view all the answers

What process contributes to the deterioration of fresh produce over time?

<p>Enzymatic activity.</p> Signup and view all the answers

What is the benefit of stir-frying vegetables until they are barely tender?

<p>Retains nutrients, texture, flavor, and color.</p> Signup and view all the answers

Why should fresh fruits and vegetables be consumed soon after harvest or purchase?

<p>To ensure maximum vitamin retention.</p> Signup and view all the answers

What is the purpose of blanching vegetables before freezing?

<p>To preserve desirable flavors, colors, and textures.</p> Signup and view all the answers

Why are certain segments of the population more prone to developing vitamin deficiency disorders?

<p>Due to increased requirements, impaired absorption, or higher excretion of vitamins.</p> Signup and view all the answers

What happens to cells when they are saturated with a vitamin?

<p>They cannot accept additional amounts of the micronutrient.</p> Signup and view all the answers

Why is it unlikely that an individual will develop a vitamin deficiency disease if their usual diet is nutritionally adequate?

<p>Because cells store vitamins to some extent, and occasional low intakes are unlikely to cause deficiencies.</p> Signup and view all the answers

What happens to the water-soluble vitamins when frozen fruits and vegetables are thawed?

<p>Water-soluble vitamins are lost in the fluid that drips out during thawing.</p> Signup and view all the answers

Why is it recommended to add fat to vegetables after they are cooked?

<p>Fat enhances the body's absorption of fat-soluble vitamins.</p> Signup and view all the answers

What causes cut fruits and vegetables to turn brown, and how can it be prevented?

<p>Damaged plant cells release an enzyme that produces brown pigments when exposed to air, and it can be prevented by sprinkling salt or sugar, coating with acidic solution, or covering with airtight plastic wrap and chilling.</p> Signup and view all the answers

Why is it important to store canned foods in a cool place?

<p>Canned foods can lose their vitamin content over time, especially if stored at high temperatures.</p> Signup and view all the answers

What happens to the vitamin content of food during the canning process?

<p>The heating of food during canning can cause the destruction of certain vitamins.</p> Signup and view all the answers

Why is it recommended to eat fresh fruits and vegetables with their edible peels or skins?

<p>To conserve vitamin content, as peels and skins are rich in vitamins.</p> Signup and view all the answers

What is the effect of overcooking and reheating on vitamin content?

<p>Prolonged heating reduces vitamin content.</p> Signup and view all the answers

Why is it recommended to cook fresh vegetables by microwaving, steaming, or stir-frying?

<p>To conserve vitamin content, as these methods use minimal water and heat.</p> Signup and view all the answers

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Study Notes

Vitamins: Basic Concepts

  • Vitamins are complex organic compounds that regulate certain metabolic processes in the body.
  • A vitamin meets four criteria:
    • The body cannot synthesize the compound or make enough to maintain good health.
    • The compound naturally occurs in commonly eaten foods.
    • Signs and symptoms of a health problem (deficiency disorder) eventually occur when the substance is missing from the diet.
    • Good health is restored if the deficiency disorder is treated early by supplying the missing substance.

History of Vitamins

  • Scurvy was a deadly disease that affected sailors on long voyages, caused by a deficiency of vitamin C.
  • James Lind discovered that citrus fruits cured scurvy in 1753, although he didn't suspect a dietary deficiency.
  • Casimir Funk discovered a substance in rice bran that cured beriberi in 1911 and coined the term "vitamine".
  • By the end of the 20th century, all vitamins had been discovered.

Roles of Vitamins

  • Vitamins play numerous roles in the body, and each has more than one function.
  • Vitamins regulate a variety of body processes, including cell division and development, and growth and maintenance of tissues.
  • Vitamins do not provide energy directly, but many participate in chemical reactions that release energy from glucose, fatty acids, and amino acids.

Antioxidants

  • Antioxidants are substances that give up electrons to radicals, protecting cells from damage.
  • Radicals are highly reactive substances with unpaired electrons that can damage cells.
  • Vitamins C and E are examples of antioxidants.

Sources of Vitamins

  • Plants, animals, fungi, and bacteria are sources of natural forms of vitamins in our diets.
  • Vitamin supplements are another source of these micronutrients.
  • Vitamins can be synthesized in a laboratory or produced by certain microorganisms.

Vitamin Enrichment and Fortification

  • Vitamin enrichment and fortification involve adding vitamins to foods during manufacturing.
  • In the United States, the federally regulated grain enrichment program specifies amounts of four B vitamins that must be added to refined wheat flour and certain other milled grain products.

Classifying Vitamins

  • Vitamins are classified as fat-soluble (A, D, E, and K) or water-soluble (B vitamins and C).
  • Fat-soluble vitamins are stored in the liver and in body fat, while water-soluble vitamins are generally not stored in the body.

Vitamin Absorption

  • The small intestine is the primary site of vitamin absorption.
  • Vitamin absorption tends to increase when the body's needs for the micronutrients are higher than usual.
  • Diseases or conditions that affect the GI tract can reduce vitamin absorption and result in deficiencies.

Vitamin Deficiency and Toxicity Disorders

  • Vitamin deficiency disorders generally result from inadequate diets or conditions that increase the body's requirements for vitamins.

  • A diet that contains adequate amounts of a wide variety of foods can help supply the vitamin needs of most healthy people.

  • Vitamin toxicity can occur when taking large oral doses of vitamin supplements or injecting vitamins into the body.### Vitamin Toxicity

  • Taking excessive amounts of vitamin supplements or consuming large amounts of vitamin-fortified foods regularly can lead to toxicity disorders.

  • Taking a "one-a-day" type of multivitamin supplement regularly is unlikely to cause toxic effects in healthy adults.

Preserving Vitamin Content of Foods

  • Fresh fruits and vegetables are highly perishable and should be eaten as soon as possible to ensure maximum vitamin retention.
  • Blanching fresh vegetables before freezing helps retain desirable flavors, colors, and textures.
  • Improper handling or lengthy storage conditions can result in substantial vitamin loss in fresh produce.
  • Selecting fresh produce carefully, avoiding bruised or wilted fruits and vegetables, and storing them properly can help retain vitamin content.
  • Vitamins like niacin and D are resistant to destruction by usual food storage conditions or preparation methods.
  • Vitamins like C, thiamin, and folate are easily destroyed or lost by improper food storage and cooking methods.

Storage and Cooking Methods

  • Store fresh fruits and vegetables in plastic packaging and chill until ready to use, except for tomatoes, bananas, and garlic which should be stored at room temperature.
  • Trim, peel, and cut raw fruits and vegetables just before eating or serving to reduce vitamin loss.
  • Cooking vegetables in small amounts of water and reusing that water for soups or sauces helps conserve water-soluble nutrients.
  • Cooking methods like microwaving, steaming, and stir-frying can conserve much of the vitamin content of the food.
  • Microwave cooking does not reduce the nutrient content of foods any more than conventional cooking methods.
  • Steaming vegetables can conserve much of the vitamin content of the produce.

Canned and Frozen Fruits and Vegetables

  • Fresh fruits and raw vegetables are not always better sources of vitamins than canned or frozen versions.
  • Frozen fruits and vegetables can be just as nutritious as fresh produce if frozen immediately after harvesting and properly stored.
  • Cooking frozen fruits and vegetables without thawing helps conserve vitamin content.
  • Canned foods can vary in nutrient content due to differences in storage times and temperatures.

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