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Nutrition (FSCN 1112) > Exam 3: Chapter 13 > Flashcards

Exam 3: Chapter 13 Flashcards

1
Q

What vitamins are considered water-soluble?

A
  • B-vitamins
    • Thiamin
    • Riboflavin
    • Niacin
    • Pantothenic acid
    • Biotin
    • Vitamin B-6
    • Folate
    • Vitamin B-12
    • Vitamin C
  • Choline*
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2
Q

Generally speaking, is the risk of toxicity from water-soluble vitamins high or low?

A
  • Generally low
  • Risk of toxicity less than fat-soluble
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3
Q

What cooking methods are best to keep vitamins in foods?

A
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4
Q

Why do we enrich food and what vitamins and minerals are added to foods for enrichment?

A

Grains are important source of B-Vitamins, but during milling the germ, bran and husk layers are removed leaving the starchy endosperm

To counteract nutrient loss from milling, nearly all bread and cereal products are enriched with 4 B-vitamins:

  • Thiamin
  • Riboflavin
  • Niacin
  • Folic Acid
  • Iron (a mineral)
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5
Q

When did enrichment begin and why?

A

Enrichment began in the 1940’s to protect against deficiency diseases.

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6
Q

Thiamin (B1) Deficiency

A
  • Beriberi
    • Sinhalese (I can’t, I can’t)
    • Impairs
      • Peripheral neuropathy
    • Two types—wet and dry
    • Congestive heart failure
  • Wernicke-Korsakoff Syndrome
    • Alcohol
      • 1) decrease absorption
      • 2) increases excretion
      • 3) poor diet
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7
Q

Thiamin Toxicity

A

No UL

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8
Q

Riboflavin (B2) Toxicity

A

No UL

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9
Q

Riboflavin (B2) Deficiency

A

Ariboflavinosis

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10
Q

Niacin (B3) Toxicity

A
  • UL: 35 mg
    • applies only to supplements and fortification
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11
Q

Niacin (B3) Deficiency

A
  • Pellagra
    • 4 D’s
    • Dermatitis, Diarrhea, Dementia– if not treated
    • Death
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12
Q

Pantothenic Acid Toxicity

A

•No UL—no known toxicity

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13
Q

Pantothenic Acid Deficiency

A

Very rare

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14
Q

Biotin Toxicity

A

No UL

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15
Q

Biotin Deficiency

A
  • Biotinase enzyme deficiency
  • Excessive consumption of raw eggs (avidin)
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16
Q

Vitamin B-6 (pyridoxine) Toxicity

A
  • UL: 100mg
    • Irreversible nerve damage
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17
Q

Vitamin B-6 (pyridoxine) Deficiency

A

Microcytic hypochromic anemia

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18
Q

Folate Toxicity

A
  • UL: 1 mg—synthetic folic acid
    • May mask B-12 deficiency
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19
Q

Folate Deficiency

A
  • Megaloblastic (macrocytic) anemia
  • Neural Tube Defects
  • Maternal deficiency of folate plus genetic predisposition
  • All women capable of getting pregnant urged to take in 400 micrograms of folic acid
  • Current fortification yields about 200 micrograms of folic acid daily
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20
Q

Vitamin B-12 (cobalamin) Toxicity

A

No UL

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21
Q

Vitamin B-12 (cobalamin) Deficiency

A
  • Pernicious Anemia
    • Inadequate production of the intrinsic factor
  • Macrocytic Anemia (megaloblastic anemia)
  • Neurological changes
    • Sensroy disturbances in the legs (burning, tingling, numbness)
    • Loss of concentration and memory
    • Disorientation and dememtia
  • Elevated plasma Homocysteine concentrations
    • Lead to heart attacks and strokes
22
Q

Vitamin C Toxicity

A

UL: 2 g

23
Q

Vitamin C Deficiency

A
  • Scurvy
  • Cancer and heart disease
24
Q

Why do smokers need additional Vitamin C? How much more do they need?

A

Smokers need several times more vitamin C than non-smokers because the effectiveness of that vitamin is decreased by nicotine.

Smokers need an additional 35 mg/day.

25
Q

What individuals are at risk of Vitamin B-12 Deficiency?

A
  • Atrophic gastritis
  • Malabsorption
    • Treatment
      • Monthly injections
      • Nasal gel
      • Very high oral doses (1-2mg)
        • Passive diffusion
  • Vegans
26
Q

What is the difference between the terms “folate” and “folic acid”, and where do each of these come from?

A

Folate is the generic name while Folic Acid is the synthetic form (ie from supplements). Folate can be found in foods such as orange juice, life cereal, and lentils.

27
Q

In terms of exposure to heat, is Niacin more or less stable compared to the other water soluble vitamins?

A

Niacin is more heat stable in comparison to other water soluble vitamins.

28
Q

What are the two forms of Niacin?

A
  • Nicotinic acid
  • Nicotinamide
29
Q

What amino acid can Niacin be synthesized from?

A

tryptophan

30
Q

What happens when riboflavin is exposed to light?

A

riboflavin is destroyed by exposure to light

31
Q

Functions of Thiamin

A

•Coenzyme form:

•thiamin pyrophosphate (TPP)

•Required for carbohydrate and branched chain amino acid metabolism

  • Decarboxylation reactions –removal of carbon dioxide
  • Glucose→Pyruvate→Acetyle-CoA
  • CAC
  • Alpha-ketoglutarate→succinyl-CoA
  • Additional B-vitamins needed for these reactions

•Pentose phosphate pathway

  • Coenzyme for transketolase
  • Converts the 6-carbon glucose to 5-carbon pentose
32
Q

Riboflavin (B2) Functions

A
  • Coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
  • Energy metabolism
    • Citric acid cycle
      • Succinate→Fumerate
    • Beta-oxidation
      • Fatty acids to acetyl-CoA—the enzyme fatty acyl dehydrogenase requires FAD
  • Other B vitamin functions
  • Antioxidant function (glutathione synthesis)
33
Q

Niacin Functions

A
  • Coenzymes: NAD+ and NADPH
  • Oxidation-reduction reactions
  • Required in at least 200 reactions especially ATP production
  • NAD+ is required for catabolism of carbohydrate, fat and protein
  • The Coenzyme Form of Niacin, NAD+ is required for Glycolysis and the Citric Acid Cycle
34
Q

Pantothenic Acid functions

A
  • Coenzyme A (acetyl-CoA)
  • Acyl carrier protein
35
Q

Biotin Functions

A
  • Coenzyme in carboxylase reactions (adds CO2)
    • Pyruvate→oxaloacetate
  • Breakdown of some AA to use as energy
  • Carboxylation of acetyl-CoA to form malonyl-CoA so fatty acids can be synthesized
36
Q

Vitamin B-6 Functions

A
  • In metabolism
  • PLP coenzyme involved in amino acid metabolism
  • Glycogenolysis
  • In immunity
  • Supports normal function and regulates gene expression
  • Synthesis of compounds
  • In the red blood cell, heme is made, neurotransmitters also made like serotonin, DOPA, GABA
37
Q

Functions of Folate

A
  • Central coenzyme form: tetrahydrofolic acid (THFA)
  • DNA synthesis
  • Amino acid metabolism
  • Neurotransmitter synthesis
    • Dopamine, norepinephrine
38
Q

Vitamin B-12 Functions

A
  • Functions
    • Cofactor in 2 enzymatic reactions
      • Formation of methionine from homocysteine
      • Enzyme methylmalonyl mutase needed for fatty acid metabolism
39
Q

Vitamin C Functions

A
  • Reduction-oxidation reactions (electron donor)
    • Cofactor for metalloenzymes
      • Ferrous (fe 2+) reduced form coverted to oxidized form (ferric, Fe3+) during enzymatic activity.
  • Collagen synthesis
    • Connective tissues
  • Synthesis of other vital compounds
    • Cholesterol to bile acids
    • Hormones—keeps metalloenzyme in the reduced state
  • Antioxidant activity
  • Iron absorption
  • Immune function
40
Q

Food Sources of Thiamin

A
41
Q

Food Sources of Riboflavin

A
42
Q

Food Sources of Niacin

A
43
Q

Food Sources of Pantothenic Acid

A
44
Q

Food Sources of Biotin

A
45
Q

Food Sources of Vitamin B-6

A
46
Q

Food Sources of Folate

A
47
Q

Food Sources of Vitamin B12

A
48
Q

Food Sources of Vitamin C

A
49
Q

Absorption, transport, storage, and excretion of Vitamin B12

A
  • Free vitamin binds to R-protein
  • Released by pancreatic lipases
  • Free vitamin then binds with intrinsic factor
50
Q

Digestion and Absorption of Vitamin B12, in detail

A
51
Q

What is intrinsic factor and why do we need this? Where is it produced?

A

Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.

Nutrition (FSCN 1112) (17 decks)

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