nutrition- chapter 7

Question 1

vitamins

Answer 1

• noncaloric
• essential for many metabolic processes
• body cannot make enough on its own, so we must obtain vitamins through diet

Question 2

functions of vitamins

Answer 2

• coenzymes
• antioxidants
• hormones that affect gene expression
• components of cell membranes
• components of rhodopsin in the eyes

Question 3

metabolism

Answer 3

• enzymes act as catalysts
• vitamin-dependent coenzymes are an integral part of some processes

Question 4

fat soluble vitamins

Answer 4

• absorbed by intestinal cells with fat
• incorporated into chylomicrons

Question 5

water soluble vitamins

Answer 5

• easily absorbed
• move directly into blood circulation
• transport does not require assistance of a carrier

Question 6

vitamin A (retinol)

Answer 6

• aids vision, growth, tissue strength, immunity
• forms: preformed vit A or retinol / provitamin A or beta-carotene
• 80% stored in liver
• deficiency can cause impaired vision, growth, reproduction, immune system, skin
• toxicity symptoms (hypervitaminosis A): bone pain, dry skin, fatigue, anorexia, hair loss, liver injury
• food sources:
  
  • preformed natural vit A: fish liver oil, liver, egg
    yolks, cream
  • beta-carotene: dark, leafy vegetables, orange
    produce

Question 7

vitamin D (calciferol)

Answer 7

• functions: Ca & P homeostasis and bone mineralization
• requirements vary per exposure to sunlight, residential latitude, and skin melanin
• deficiency symptoms: rickets, muscle weakness, cancer, coronary heart disease, hypertension, stroke, tuberculosis, obesity, t2 diabetes, macular degeneration, neurologic disorders, and autoimmune diseases
• toxicity symptoms: fragile bones, kidney stones, calcification of soft tissues, elevated blood calcium
• food sources: fatty fish, fortified foods

Question 8

vitamin E (tocopherol)

Answer 8

• functions: antioxidant function, immune function, cell signaling, selenium metabolism
• deficiency symptoms: hemolytic anemia in premature infants, myelin synthesis disruption in individuals who cannot absorb or metabolize fat
• toxicity symptoms: excessive supplemental α-tocopherol intake may interfere with vitamin K activity and blood clotting
• food sources: vegetable oils, nuts, seeds, and fortified cereals
• stability: unstable to heat and alkalis

Question 9

vitamin K

Answer 9

• functions: blood clotting and bone development
• requirements: supply is normally available to support body needs
• deficiency symptoms: primary deficiency uncommon; deficiency may be secondary to another clinical condition; infants routinely receive vitamin K injections at birth to prevent hemorrhaging
• toxicity is rare
• food sources: green leafy vegetables

Question 10

Warfarin (Coumadin)

Answer 10

• anticoagulant
• inexpensive
• must have consistent amount of vitamin K to ensure right dose

Question 11

vitamin C (ascorbic acid)

Answer 11

• function: connective tissue, metabolism, antioxidant/ immune function
• requirements: additional vit C for smokers
• deficiency symptoms: issue bleeding joint bleeding, susceptibility to bone fracture, poor wound healing, bleeding gums, and tooth loss, scurvy
• toxicity: UL is 2000mg/day. excess may cause GI disturbance
• food sources: citrus fruits, bell peppers, and kiwis, berries, broccoli, tomato juice, and other green and yellow vegetables
• stability: oxidizes with exposure to air and heat, unstable in alkaline mediums; highly soluble in water

Question 12

Thiamin (B1)

Answer 12

• functions: metabolic reactions related to ATP
• requirements: increases with body’s demand for ATP
• deficiency: effects energy availability. seen often with alcoholism
• toxicity: no evidence of toxicity from oral intake
• food sources: yeast, pork, whole or enriched grains, legumes

Question 13

riboflavin (B2)

Answer 13

• functions: macronutrient metabolism, metabolic reactions
• requirements vary with energy needs
• deficiency: impacts rapid cell regeneration; cracked lips, swollen tongue, burning eyes, skin fold dermatitis; ariboflavinosis
• no reported toxicity from oral intake
• milk, enriched grains, meats, almonds, soybeans
• stability: can be destroyed by light

Question 14

niacin (B3)

Answer 14

• functions: macronutrient metabolism, DNA repair, steroid hormone synthesis
• requirements vary with energy needs
• deficiency symptoms: weakness, poor appetite, indigestion, skin and nervous system disorders, pellagra
• side effects: reddened flush, burning, tingling, and itching; UL is 35mg/day
• food sources: meat, poultry, fish, bread products, ready-to-eat cereals, peanuts

Question 15

B6 (pyridoxine)

Answer 15

• functions: protein metabolism, cell reactions that involve amino acids, neurotransmitter synthesis
• requirements vary by protein intake/utilization
• deficiency symptoms: abnormal CNS function, microcytic hypochromic anemia
• toxicity: large supplemental doses can cause uncoordinated movement and nerve damage; UL for adults at 100 mg/day
• food sources: grains, enriched cereals, liver, kidneys, other meats, legumes

Question 16

Folate

Answer 16

• functions: DNA synthesis, cell division, glycine synthesis, reduction of blood homocysteine concentration, gene expression
• requirements: dietary folate equivalencies (DFEs); women capable of becoming pregnant: 400mcg/day of synthetic folic acid from fortified foods or supplements in addition to natural folate found in food
• deficiency symptoms: birth defects, poor growth in children, weakness, depression, and neuropathy
• toxicity symptoms: excessive folic acid masks vitamin B12 deficiency; adult UL for supplemental folic acid is 1000mcg/day
• food sources: green, leafy vegetables; orange juice; legumes; and chicken liver; fortified products
• stability: destroyed by heat

Question 17

B12 (cobalamin)

Answer 17

• functions: DNA synthesis, cell division
• requirements: a mixed diet that includes animal foods easily meets needs
• deficiency: due to poor absorption, age; fatigue, anorexia, and nausea; hematologic, neurologic, and digestive manifestations in advanced cases
• no known toxicity from oral intake
• food sources: beef liver, lean meat, clams, oysters, herring, and crab
• stable through ordinary cooking

Question 18

pantothenic acid

Answer 18

• functions: cellular metabolism, protein acetylation and protein acylation
• requirements: 4-7 mg/day
• deficiency: synthetic diets that contain virtually no pantothenic acid are the only known cases
• no known toxicity from oral intake
• food sources: animal tissues, whole-grain cereals, fortified cereals, sunflower seeds, milk, eggs, and some vegetables

Question 19

biotin

Answer 19

• function: coenzyme for five carboxylase enzymes
• requirements: small
• no natural deficiency
• no known toxicity
• food sources: liver, cooked egg yolk, soy flour, cereals, meats, tomatoes, yeast

Question 20

choline

Answer 20

• functions: structural integrity of cell membranes, neurotransmission
• deficiency: due to long-term TPN devoid of choline; seen in fatty liver disease
• toxicity symptoms: depressed blood pressure, fishy body odor, sweating, excessive salivation, and reduced growth rate
• food sources: soybean products, eggs, liver, and other meat products

Question 21

plant nutrients (phytochemicals)

Answer 21

• function: antioxidant and anti-inflammatory activity, hormonal actions, interactions with enzymes and DNA replication, and antibacterial effects
• no established DRIs
• food sources: whole and unrefined foods such as vegetables, fruits, legumes, nuts, seeds, whole grains, and certain vegetable oils

Question 22

supplementation principles

Answer 22

• read labels carefully
• vitamins can be harmful in large amounts
• professional should determine individual’s need
• all nutrients work together to promote good health
• food is the best source of nutrients
• evaluate the information

Question 23

megadoses

Answer 23

nutrients and drugs can:
1. improve conditions or illness
2. prevent disease
3. relieve symptoms

• excessive doses may result in toxic side effects
• great potential for fat-soluble vitamin toxicity
• megadoses can produce toxic effects and cause a secondary deficiency

Question 24

functional foods

Answer 24

• whole foods with added nutrients, such as vitamins, minerals, herbs, fiber, protein, or essential fatty acids that may have beneficial health effects
• Academy of Nutrition and Dietetics recognizes possible benefit
• recommendations for intake not established