Chapter 10- Nurition

81) How might homocysteine damage arteries and contribute to heart disease?

: It may be that excessive amounts of homocysteine injure the arteries, decrease the flexibility of the blood vessels, or increase the likelihood of clots forming in the blood

10) Which of the following is converted to niacin when needed? A) tryptophan B) methionine C) lysine D) phenylalanine

A

12) Pantothenic acid makes up part of ________, the gateway molecule in energy metabolism. A) acetyl CoA B) NAD C) pyruvate D) oxaloacetate

A

13) If a breakfast contains 0.18 g of tryptophan, calculate the total amount of niacin in the meal (excluding any preformed niacin). A) 3 mg niacin B) 5 mg niacin C) 10 mg niacin D) 18 mg niacin

A

17) Too much folate in the diet masks the symptoms of B12 deficiency anemia. This may lead to which of the following problems? A) nerve damage B) skin rash C) diarrhea D) neural tube defects

A

2) B vitamins share a role as ________ in energy production. A) coenzymes B) enzymes C) oxidants D) metabolites

A

20) Which vitamin requires a carrier called transcobalamin for transport throughout the circulation? A) vitamin B12 B) thiamin C) niacin D) pantothenic acid

A

21) Joan is thinking about becoming a vegan. Her mother warns her that her diet will be lacking which vitamin? A) B12 B) biotin C) B6 D) niacin

A

22) Which food should be eaten in order to enhance the bioavailability of iron? A) oranges B) milk C) whole-grain bread D) salmon

A

26) All of the following are classified as B vitamins except A) choline. B) niacin. C) pantothenic acid. D) pyridoxine.

A

28) The best way to prevent colds is to A) wash your hands regularly. B) take vitamin C supplements. C) take echinacea supplements. D) take cobalamin supplements.

A

32) Which vitamin acts as an antioxidant and helps neutralize free radicals? A) vitamin C B) biotin C) pantothenic acid D) pyridoxine

A

6) An advanced form of thiamin deficiency seen in alcoholics is A) Wernicke-Korsokoff syndrome. B) scurvy. C) pellagra. D) pernicious anemia.

A

87) Describe the possible outcomes of a folate deficiency.

A folate deficiency results in: • abnormally large and immature cells known as megaloblasts • megaloblasts develop into abnormally larger red blood cells, or macrocytes • eventually, macrocytic anemia causes a person to feel tired, weak, and irritable and to experience shortness of breath.

85) In addition to foodborne illnesses, why is it not a good idea to consume raw eggs?

Avidin can bind up to four molecules of biotin, which renders the vitamin unavailable for absorption.

1) When consumed in excess, water-soluble vitamins are most often A) stored in the liver. B) excreted in the urine. C) excreted in the feces. D) stored in body fat.

B

14) Folate has been shown to help reduce the risk of certain cancers, specifically ________ cancer. A) lung B) colon C) skin D) liver

B

25) Recent research indicates that vitamin B6, along with folate and vitamin B12, may help reduce the risk of A) colon cancer. B) heart disease. C) diabetes. D) obesity.

B

27) Which of the following individuals is most likely to benefit from a vitamin C supplement? A) a vegan B) a person under acute stress C) a person with a cold D) all of the above

B

30) To increase your intake of vitamin B12, eat all the following foods except A) cheese. B) pasta. C) eggs. D) tuna.

B

33) Which vitamin is needed during transamination to create nonessential amino acids? A) biotin B) vitamin B6 C) vitamin C D) vitamin B12

B

37) A food source rich in biotin is A) spinach. B) peanuts. C) egg whites. D) white flour.

B

39) Milk, yogurt, and grains are rich sources of which vitamin? A) thiamin B) riboflavin C) vitamin C D) vitamin B12

B

5) Sandy was cooking beans for dinner and heard they cook faster if baking soda is added to the water. Is adding baking soda a good idea? A) Yes, it protects the vitamins in the food from being destroyed by the heat. B) No, it destroys the thiamin in the beans. C) Yes, it adds folate to the foods. D) No, it inactivates the vitamin C present.

B

7) All of the following are true about thiamin except A) a deficiency is called beriberi. B) polyneuritis is a symptom of an excessive intake of thiamin. C) it was the first B vitamin to be discovered. D) lean pork is the most nutrient-dense source of naturally occurring thiamin.

B

11) All of the following are correct concerning pellagra except A) diarrhea may be a symptom. B) dementia may be a symptom. C) it is due to a deficiency of pantothenic acid. D) it was widespread among the poor living in the southern United States in the early 1900s.

C

15) The incidence of neural tube defects has decreased now that some foods are enriched with ________. A) niacin B) vitamin C C) folic acid D) carnitine

C

24) Where is vitamin B6 activated to form its active form, pyridoxal phosphate (PLP)? A) mouth B) stomach C) liver D) pancreas

C

29) In which organ is intrinsic factor made? A) pancreas B) colon C) stomach D) salivary glands

C

34) A sign of a B6 deficiency is A) pellagra. B) beriberi. C) microcytic hypochromic anemia. D) pernicious anemia

C

40) Which of the following is not a symptom of riboflavin deficiency? A) reduced conversion of vitamin B6 to its active form B) inflamed tissues in the mouth and throat C) soreness in the soles of the feet D) altered iron metabolism

C

9) Which B vitamin is part of NAD+, which carries the H+ to the electron transport chain? A) thiamin B) riboflavin C) niacin D) biotin

C

95) Describe the function and typical sources of carnitine.

Carnitine is needed to properly utilize fat in the diet. It is found in animal products, such as meat and dairy.

16) A deficiency of _________ can lead to macrocytic anemia. A) pantothenic acid or riboflavin B) biotin or niacin C) thiamin or riboflavin D) folate or vitamin B12

D

18) Which of the following is a function of choline in the body? A) It is part of the phospholipid that makes up cell membranes. B) It participates in nerve transmission. C) It assists in the transport of lipids. D) All of the above are functions of choline.

D

19) Which is true about carnitine supplements? A) They help promote weight loss. B) They improve athletic performance. C) They reduce the risk of cataracts. D) None of the above is true of carnitine supplements.

D

23) Vitamin C is involved in all of the following except A) collagen synthesis. B) tyrosine synthesis. C) neurotransmitter synthesis. D) DNA synthesis.

D

3) Many water-soluble vitamins can be lost or destroyed by exposure to A) heat, light, and cold. B) light, cold, and loud noises. C) darkness, cold, and air. D) heat, light, and air.

D

31) Why does vitamin B12 absorption decrease with age? A) a reduction in hydrochloric acid in the stomach B) a reduction in intrinsic factor production C) a lack of necessary pancreatic enzymes D) all of the above

D

35) Which of the following is correct about riboflavin? A) Its active form is coenzyme A. B) It is only found in animal foods. C) It is important in the synthesis of collagen. D) Ariboflavinosis is the name for its deficiency.

D

36) Which of the following is a function of biotin? A) It helps prevent scurvy. B) It helps to reduce cholesterol. C) It has an antioxidant effect on free radicals. D) It acts as a coenzyme in fatty-acid synthesis.

D

38) Which vitamin is found in so many foods that its name is derived from a word meaning "everywhere"? A) thiamin B) niacine C) riboflavin D) pantothenic acid

D

4) Some research has supported the assertion that B vitamins may reduce the risk of A) heart disease. B) diabetes. C) loss of cognitive function. D) A and C

D

8) Packaging milk in cardboard containers is a way to prevent destruction of which vitamin by ultraviolet light? A) thiamin B) vitamin C C) niacin D) riboflavin

D

79) How are excess water-soluble vitamins excreted?

Excess water-soluble vitamins are usually excreted in the urine.

41) Diarrhea is the first side effect to be observed when too much niacin is consumed. T/F

FALSE

44) Consuming large amounts of vitamin C through supplements will turn urine yellow. T/F

FALSE

46) Eggs are the most nutrient-dense source of naturally occurring thiamin. T/F

FALSE

48) Chronic alcohol abuse can lead to an advanced form of thiamin deficiency called pellagra. T/F

FALSE

50) Milk is packaged in opaque cartons to prevent the degradation of biotin. T/F

FALSE

53) The B vitamins contain 4 kilocalories per gram T/F

FALSE

54) Vitamin C plays an important role as a coenzyme. T/F

FALSE

57) Vitamin C is helpful in reducing the number of colds a person will contract. T/F

FALSE

58) Vitamin B12 is abundant in citrus fruits and cruciferous vegetables. T/F

FALSE

59) Individuals with pernicious anemia are given injections of pantothenic acid. T/F

FALSE

62) Vitamin B6 is useful in treating premenstrual syndrome. T/F

FALSE

64) Adding raw eggs to a healthy diet is a good way to obtain adequate biotin. T/F

FALSE

66) Most water-soluble vitamins are highly toxic when consumed in excess. T/F

FALSE

67) In foods, water-soluble vitamins are usually attached to proteins and must be released in order to be absorbed. T/F

FALSE

68) The enrichment of foods with biotin has reduced the incidence of neural tube defects by over 25 percent. T/F

FALSE

70) Flushing is the first side effect to be observed when too much riboflavin is consumed T/F

FALSE

74) Of the nine water-soluble vitamins, seven of them are B-complex vitamins. T/F

FALSE

82) Why are beriberi and pellagra rare in the United States today?

In the United States, refined grains are enriched with thiamin and niacin, so instances of beriberi and pellagra are rare.

86) What is the best way to decrease the risks of neural tube defects, and what steps have been taken by the FDA to help reduce risk?

Increasing consumption of folate before conception and during pregnancy has been shown to help decrease incidence of spina bifida and other neural tube defects. The FDA has mandated that synthetic folate be added to enriched grains and cereal products.

94) What is the molecular structure of folate?

It has three parts: pteridine, para-aminobenzoic acid (PABA), and at least one glutamate.

97) What causes pellagra, and why is it known as the "disease of the three Ds"?

It is caused by niacin deficiency. Its three main symptoms-dermatitis, dementia, and diarrhea-led to three-Ds label

96) Explain the cause and effects of ariboflavinosis.

It is caused by riboflavin deficiency and can result in inflamed tissues in the throat, mouth, tongue, and lips.

92) What is hemopoiesis, and which vitamins play a role in it?

It is the formation of red blood cells, a process aided by folate and vitamin B12.

78) What environmental factors can degrade or destroy vitamins?

Many water-soluble vitamins are easily destroyed by heat, light, pH, or oxidation.

83) What is a characteristic symptom of excessive niacin intake?

Overconsuming niacin (more than one gram per day) by taking supplements or eating too many overly fortified foods can cause flushing, a reddish coloring of the face, arms, and chest.

93) Describe the cause and symptoms of scurvy.

Scurvy is caused by vitamin C deficiency. Symptoms include swollen and bleeding gums, a rough rash, coiled or curly arm hairs, and wounds that don't heal.

80) What are coenzymes?

Substances, often vitamins, that bind to an enzyme to facilitate enzyme activity; the coenzyme is not permanently altered by the chemical reaction

98) Describe the symptoms of pantothenic acid deficiency.

Symptoms may include fatigue, nausea, vomiting, numbness, muscle cramps, and difficulty walking. During World War II, prisoners reported "burning feet" syndrome due to lack of pantothenic acid in their diet.

42) Niacin supplements have been shown to raise the level of the HDL cholesterol carrier. T/F

TRUE

43) Niacin found in plant foods, such as wheat or corn, is much less bioavailable than niacin from meat and dairy products. T/F

TRUE

45) Thiamin is one vitamin that is sensitive to changes in pH. T/F

TRUE

47) Numerous studies have suggested that low blood levels of some B vitamins are associated with an increased level of homocysteine in the body. T/F

TRUE

49) Peripheral neuropathy is a classic symptom of beriberi T/F

TRUE

51) Niacin is stable in foods and is not destroyed by heat or ultraviolet light. T/F

TRUE

52) Pantothenic acid makes up part of the metabolic compound acetyl CoA. T/F

TRUE

55) Folate found naturally in foods is less bioavailable than folate found in supplements or fortified foods. T/F

TRUE

56) Like beta-carotene and vitamin E, vitamin C acts as an antioxidant that may help reduce the risk of chronic diseases such as heart disease and cancer. T/F

TRUE

60) Individuals over the age of 50 should meet their vitamin B12 needs primarily from fortified foods or a supplement. T/F

TRUE

61) Vitamin B12 stimulates osteoblast activity for healthy bone. T/F

TRUE

63) If adequate amounts of vitamin B6 are not consumed, microcytic hypochromic anemia may develop. T/F

TRUE

65) If necessary, the amino acid tryptophan can be converted to niacin. T/F

TRUE

69) Choline is widely available in foods, so a deficiency is unlikely. T/F

TRUE

71) Vitamin C is involved in the production of collagen, which is the most abundant protein in the body. T/F

TRUE

72) Supplements of niacin have been used to lower the total amount of cholesterol in the blood. T/F

TRUE

73) Keeping milk in glass bottles runs the risk of destroying much of its riboflavin. T/F

TRUE

75) Vitamin C, also known as ascorbic acid, cannot be synthesized by the human body and must be obtained through food or supplements. T/F

TRUE

77) In what way does vitamin C help maintain a healthy immune system?

Vitamin C helps maintain a healthy immune system by enabling the body to make white blood cells

76) Which three vitamins act as antioxidants?

Vitamin C, beta-carotene, and vitamin E are the antioxidant vitamins.

88) Name some ways water-soluble and fat-soluble vitamins differ.

Water-soluble vitamins (versus fat-soluble vitamins): • are excreted in excess (stored in excess) • are less likely to be toxic (more likely) • are soluble in water (soluble in fat) • are easily destroyed by light, heat, and air (generally more stable)

84) How does absorption of some vitamins, such as pantothenic acid, differ when intake is low or intake is high?

When intakes are low, some vitamins are absorbed by active transport and when intakes are high, by passive transport across the intestinal wall.

99) What are the symptoms of biotin deficiency?

dermatitis (especially around the eyes, nose, and mouth), conjunctivitis, hair loss, and alterations in the nervous system resulting in lethargy, hallucinations, and depression

90) When, how, and by whom was thiamin discovered?

• In the 1890s in east Asia, a Dutch doctor, Christiann Eijkman, paved the way for the discovery of thiamin. • He noticed that chickens and pigeons that ate polished rice developed polyneuritis. • Eijkman noted that polyneuritis was also a symptom of beriberi in humans. • Eijkman changed the birds' diet and the birds recovered. • In 1911, Casimir Funk identified thiamin as the curative factor in the unpolished rice.

List the best food sources for the following vitamins: riboflavin, folate, vitamin B12, vitamin C.

• Riboflavin: milk, yogurt, enriched cereals and grains • Folate: enriched cereals, grains, pastas, and flours; dark green vegetables • B12: animal products, such as meat, fish, poultry, and dairy • C: vegetables and fruit

89) Describe how a coenzyme affects how an enzyme functions.

• Two compounds approach the enzyme, but a coenzyme is needed for the reaction to occur. • Once the coenzyme is present, the compounds can interact with the enzyme. • The enzyme changes shape. • The reaction occurs, and the product is released.

91) What is Wernicke-Korsakoff syndrome and who is most susceptible?

• an advanced form of thiamin deficiency • progressively damaging brain disorder that can cause mental confusion and memory loss, difficulty seeing clearly, low blood pressure, uncontrolled movement of the arms and legs, and even coma • Alcohol consumption interferes with the absorption of the small amounts of thiamin that may be in the diet. • Those who chronically abuse alcohol tend to have a poor diet that is probably deficient in thiamin.