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21. Nutritional biochemistry Flashcards

1
Q

What are the four proproteases secreted by the pancreas?

A

Tripsinogen
Chymotrypsin
Proelastase
Procarboxypeptidases

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2
Q

What are the active enzymes secreted by the pancreas?

A 
Alpha-amylase
Lipases
Colipase
Phospholipases
Cholesterol esters
RNAase
DNAase
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3
Q

What is the key ion secreted by the pancreas?

A

HCO3-

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4
Q

What are the three stages of pancreatic secretion?

A

Cephalic
Gastric
Intestinal

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5
Q

What mediates pancreatic secretion in the cephalic phase?

A

Acetylcholine

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6
Q

What mediates pancreatic secretion in the gastric phase?

A

Acetylcholine

Gastrin

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7
Q

What mediates pancreatic secretion in the intestinal phase?

A

Cholecystokinin

Secretin

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8
Q

What is HCO3- secretion by pancreatic duct cells controlled by?

A

Acetylcholine

Secretin

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9
Q

What are the three types of lipase?

A

Lingual
Gastric
Pancreatic

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10
Q

Though lingual lipase and gastric lipase can act on their own, what does pancreatic lipase require for proper function?

A

Bile salts

Colipase

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11
Q

What are the three types of enzymes responsible for the digestion of fat?

A

Lipase (lingual, gastric, pancreatic)
Phospholipases
Cholesterol esterases

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12
Q

What components of fat can be taken up directly into an enterocyte?

A

Glycerol
Short chain fatty acids
Medium chain fatty acids

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13
Q

What components of fat are taken up in a mixed micelle?

A

Cholesterol
Lysophospholipids
Long chain fatty acids
Monoacylglycerols

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14
Q

What are the two main types of proteases?

A

Endopeptidases: cleaves in the center or proteins and peptides
Exopeptidates: cleaves from the N or C terminal ends of peptides and proteins

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15
Q

What is the endopeptidase in the stomach? What secretes it?

A

Pepsinogen–chief cells

**activated by acid and auto-activation

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16
Q

What synthesizes and secretes the endopeptidases of the duodenum and jejunum?

A

Alpha cells of the pancreas

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17
Q

How is the endopeptidase trysinogen activated?

A

Activated by epithelial enteropeptidase/enterokinase

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18
Q

What is chymorypsinogen and proelastase activated by?

A

Typsin

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19
Q

What are the two exopeptidases secreted into the duodenum?

A

Carboxypeptidases

Aminopeptidases

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20
Q

What synthesizes the exopeptidase carboxypeptidase vs aminopeptidase?

A

Carboxypeptidase: alpha cells of the pancreas
Aminopeptidase: intestinal epithelial cells

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21
Q

What are the three types of protein transporters found in the duodenum and jejunum?

A

Amino acid class specific
Dipeptide
Tripeptide

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22
Q

What are the two kinds of epithelial cell peptidases?

A

Tripeptidase

Dipeptidase

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23
Q

What enzyme digests carbs and is active in the oral cavity, early in the stomach?

A

Salivary alpha amylase

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24
Q

What enzyme disgests carbs and is acitve in the lumen of the duodenum?

A

Pancreatic alpha amylase

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25
Q

Where are the di and trisacchridases located?

A

Intestinal epithelial cell membranes (brush borders)

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26
Q

Where are carbohydrates absorbed?

A

Duodenum

Jejunum

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27
Q

What are the two transporters for the absorption of carbohydrates?

A

SGLT1

GLUT5

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28
Q

What are the sx of lactase deficiency? Cause?

A

Bloating and diarrhea due to the bacterial degradation of lactose (upon delivery to the large intestine undigested)

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29
Q

What gets removed in a typical RNY bypass of the small intestine?

A

Stomach
Duodenum
Part of the jejunum

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30
Q

What do calorie requirements depend on?

A

Energy expendature: BMR, thermal effect of food, physical activity

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31
Q

What are the two essential fatty acids?

A

Linoleic acid: w 3

Linolenic acid: w 6

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32
Q

What are the essential amino acids?

A 
Arginine
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine 
Threonine
Tryptophan
Valine
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33
Q

What has the highest calorie density of carbs, proteins, fat, alcohol

A

Fat 9kcal/gm
Alcohol 7 kcal/gm
Carbs 4kcal/gm
Proteins 4kcal/gm

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34
Q

What % of diet should carbs, proteins, and fat compose?

A

Carbs 45-65%
Proteins 10-35%
Fat 20-35%

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35
Q

6 causes of malnutrition

A 
Poverty
Ignorance
Chronic alcoholism
Acute and chronic illness
Self-imposed dietary restriction
Other: GI disease, malabsorption syndrome, drugs, TPN
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36
Q

A malnourished child has a weight of less than __% normal

A

80%

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37
Q

What are the two protein storing compartments?

A

Somatic protein: skeletal muscle stores

Visceral protein: visceral organ stores

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38
Q

What is marasmus?

A

Severe reduction in caloric intake leading to >60% reduction in body weight

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39
Q

What protein compartment is depleted in marasmus?

A

Somatic protein compartment

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40
Q

What is the presentation of marasmus?

A

Growth retardation and loss of muscle mass
Emaciated extremities
Anemia and immunodeficiency

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41
Q

What protein stores are lost in Kwashiorkor?

A

Visceral protein stores

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42
Q

What causes Kwashiorkor?

A

Protein deprivation is greater than caloric deprivation
Protein malabsorption
Chronic protein loss: protein losing enteropathies, nephrotic syndrome, chronic diarrhea

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43
Q

Is albumin abnormal in Kwashiorkor or masasmus?

A

Kwashiorkor: hypoalbuminemia

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44
Q

What is the clinical presentation of Kwashiorkor?

A

Alternating hypo and hyperpigmented zones with desquamination
Hair color and texture changes
Fatty liver
Immune deficiency, anemia

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45
Q

What are the patient populations that frequently show malnutrition?

A

Chronically ill
Hospitalized
Advanced cancer
AIDS

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46
Q

Four complications of malnutrition:

A

Infection
Impaired wound healing
Sepsis
Death after surgery

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47
Q

How is the BMI calculated

A

BMI = weight (kg) / height (m2)

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48
Q

What are the key limitations to using BMI?

A

High muscle mass
High bone mass
Ranges change for children and teens

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49
Q

Two measurements for the % body fat?

A

Skinfold

Impedance

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50
Q

What are the characteristics of metabolic syndrome?

A 
Obesity
Insulin resistance 
Hypertriglyceridemia 
Low HDL
Hypertension
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51
Q

What are the characteristic of type II diabetes?

A

Elevated blood sugars
Non-insulin dependent
Insulin resistance

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52
Q

How is type II diabetes controlled?

A

Weight loss
Exercise
+/- medications

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53
Q

What are the key medical complications of obesity?

A 
Metabolic syndrome
Type II diabetes
Cardiovascular morbidity 
Cholelithiasis
Cancers
PE/DVT
Obstructive sleep apnea
Hypoventilation syndrome
Osteoarthritis 
Steatosis
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54
Q

What are the 4 Fs of cholelithiasis?

A

Femal
Fertile
Forty
Fat

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55
Q

What are the estrogen dependent cancers that are associated with obesity?

A

Endometrial hyperplasia/carcinoma

Breast cancer

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56
Q

What are the estrogen independent cancers that are associated with obesity?

A

Colon cancer
Kidney cancer
Esophageal cancer

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57
Q

Why is PE/DVT associated with obesity?

A

Estrogen is a RF for thrombosis

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58
Q

What are the three hyperlipidemias that are associated with accelerated, premature atheroscleorosis of the coronary arteries

A

Familial hypercholesterolemia
Hypertriglyceridemia
Familial combined hyperlipidemia

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59
Q

What is the “Recommended Dietary Allowance” (RDA)?

A

Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) of healthy individuals

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60
Q

What is the definition of adequate intake?

A

Established when evidence is insufficient to develop an RDA and is set as a level assumed to ensure nutritional adequacy

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61
Q

What is a tolerable upper intake level?

A

Maximum daily intake unlikely to cause adverse side effects

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62
Q

What are ‘daily values’ used for?

A

Food and dietary supplement labels to indicate the percent of the recommended daily amount of each nutrient that a serving provides

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63
Q

What are the two general types of water soluble vitamins

A

Non B-complex

B-complex

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64
Q

What is the non-B complex water soluble vitamin?

A

Ascorbate (Vitamin C)

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65
Q

What are the three types of B-complex, water soluble vitamins

A

Energy releasing
Hematopoietic/1C metabolism
Amino acid metabolism

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66
Q

What are the energy-releasing, B-complex, water soluble vitamins?

A 
Thiamine (B1)
Riboflavin (B2)
Niacin (B3)
Pantothenic acid (B5)
Biotin (B7)
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67
Q

What are the hematopoietic/1C metabolism, B-complex, water soluble viatmins?

A 
Folate (B9)
Vitamin B12 (cobalamin)
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68
Q

What is the amino acid metabolism, B-complex, water soluble vitamin?

A

Vitamin B6 (pyridoxine, pyridoxamine)

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69
Q

What are the fat soluble vitamins?

A 
Vitamin A (retinol, carotenes)
Vitamin D (cholecalciferol)
Vitamin E (tocopherols)
Vitamin K (phylloquinones)
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70
Q

Where are most B vitamins absorbed? What is the exception?

A

Duodenum and jejunum

B12 absorbed in the ileum and mircobiota-produced biotin in the large intestine

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71
Q

What are the sources of most B-vitamins

A 
Meats
Milk
Whole grains and fortified breads/cereals
Legumes 
Nuts
Green leaky vegetables
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72
Q

What are the sources of vitamin B12

A 
Meat 
Shellfish
Fish
Eggs
Milk, cheese, yogurt
**not available in plant products
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73
Q

What vitamin is thiamine pyrophosphate dependent on?

A

Thiamine

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74
Q

What vitamin is flavin adenine dinucleotide dependent on?

A

Riboflavin

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75
Q

What vitamin is nicotinamide adenine dinucleotide dependent on?

A

Niacin

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76
Q

Where is thiamine (B1) absorbed?

A

Duodenum

Jejunum

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77
Q

How long does it take for thiamine (B1) storage to be depleted

A

14 days

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78
Q

What is the active from of thiamine (B1)?

A

Thiamine pyrophosphate

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79
Q

What are three key functions of thiamine (B1)?

A
  1. Cofactor for pyruvate dehydrogenase (decarboxylation)
  2. Cofactor in the pentose phosphate pathway
  3. Maintains neural membranes and normal nerve conduction
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80
Q

What are dietary sources of thiamine (B1)

A

Pork
Whole grains and fortified breads/cereals
Legumes and nuts

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81
Q

Who commonly gets thiamine (B1) deficiency?

A

Alcoholics

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82
Q

What are the three clinical syndromes of thiamine (B1) deficiency

A
  1. Polyneuropathy–dry beriberi
  2. Dilated cardiomyopathy–wet beriberi
  3. Wernicke-Korsakoff syndrome
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83
Q

What are two possible treatments for thiamine (B1) deficiency

A 
Banana bag (IV Mg, K, thiamine, folate)
Oral supplementation
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84
Q

What is Wernicke-Korsakoff Syndrome?

A

Reversible encephalopathy with opthalmoplegia, confusion and disorientation, nystagmus, and ataxia
Cause: Thiamine (B1) deficiency

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85
Q

What is the chronic stage of Wernicke Korsakoff syndrome?

A

Korsakoff syndrome: irreversible memory disturbances and confabulation

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86
Q

What is seen in the brain with Wernicke-Korsakoff syndrome?

A

Periventricular and mammilary body hemorrhage and necrosis

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87
Q

Is thiamine (B1) toxic?

A

Non-toxic–excess excreted

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88
Q

What vitamin is panthothenic acid

A

B5

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89
Q

Where is panthothenic acid (B5) absorbed?

A

Duodenum

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90
Q

Storage of pantothenic acid

A

Excess excreted, very little stored

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91
Q

What is the active form of panthothenic acid (B5)

A

Coenzyme A

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92
Q

What is the function of pantothenic acid (B5)

A

Carbohydrate and fatty acid synthesis

**acyl carrier protein function

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93
Q

What are good sources of panthothenic acid?

A

Whole grains
Meats
Fish
Poultry

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94
Q

Panthothenic acid deficiency ? Toxicity

A

Very rare

non-toxic

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95
Q

What vitamin is riboflavin

A

B2

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96
Q

Where is riboflavin (B2) absorbed?

A

Duodenum

Jejunum

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97
Q

What are the active forms of riboflavin

A 
Flavin mononucleotide (FMN)
Flavin adenine dinucleotide (FAD)
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98
Q

What is the function of riboflavin (B2)

A

Electron carrier: complex dehydrogenases, citric acid cycle to the electron transport chain

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99
Q

What are good sources of riboflavin?

A 
Milk and milk products
Eggs
Meat
Fish
Whole grains and fortified breads/cereals
Nuts and legumes
100
Q

Who gets riboflavin (B2) deficiency?

A

Rare, except in alcoholics

101
Q

What are the s/s of riboflavin (B2) deficiency?

A

Cheilosis: scaling and fissures at the mouth corners
Angular stomatitis: inflammation at the corners of the mouth
Glossitis: inflammation of the tongue
Dermatitis

102
Q

Toxicity of riboflavin (B2)

A

non-toxic, excreted

103
Q

What vitamin is niacin?

A

B3

104
Q

Where is niacin absorbed?

A

Duodenum

Jejunum

105
Q

What are the active forms of niacin (B3)

A

NADPH/NADP+

NADH/NAD+

106
Q

When is NADH generated? Function?

A

Generated during degradation of carbs, fats, amino acids, nucleic acids
Carried electrons from the TCA cycle to the electron transport chain

107
Q

When is NADPH generated? Function?

A

Glucose-6-phosphate dehydrogenase in the pentose phosphate pathway
Used in synthesis reactions for carbohydrates, fats, amino acids, and nucleic acids

108
Q

What are good dietary sources of niacin (B3)

A 
Meat
Fish
Milk 
Eggs
Whole grains and fortified cereal/breads 
Nuts and legumes
109
Q

What is the name fore niacin or tryptophan deficiency?

A

Pellagra

110
Q

Who gets pellagra (niacin or tryptophan deficiency)?

A

Alcoholics

People living in poverty

111
Q

What are the three key sx of pellagra?

A

Dermatitis (when exposed to the sun)
Diarrhea
Dementia

112
Q

What is the toxicity of niacin (B3) when given at pharmacological levels for hypercholesterolemia?

A

Flushing
Gastric irritation
Rashes

113
Q

What vitamin is biotin?

A

B7

114
Q

Where is biotin (B7) absorbed?

A

Duodenum

Jejunum

115
Q

What is the active form of biotin (B7)?

A

Biotin bound to carboxylase

116
Q

WHat is the function of biotin (B7)?

A

Carboxylase cofactor: pyruvate carboxylase and acetyl CoA carboxylase

117
Q

What are dietary sources of biotin (B7)

A 
Liver
Milk
Eggs
Fish
Peanuts
Chocolate
Whole grains
Legumes
118
Q

Where in the body is biotin synthesized?

A

By intestinal bacteria

119
Q

What can lead to biotin (B7) deficiency?

A

Rare, but more prevalent in the elderly

Can occur by binding of biotin to avidin in raw egg whites

120
Q

What happens in a biotinidase deficiency?

A

Inability to convert dietary-derived biocytin to free biotin

121
Q

What is the presentation of biotin deficiency in infants?

A

Poor growth

Neurological disorders

122
Q

What is the presentation of biotin deficiency in infants and adults?

A

Dermatitis

Alopecia

123
Q

Biotin toxicity?

A

None–excess is excreted

124
Q

What vitamin is pyridoxine?

A

B6

125
Q

Where is pyridoxine absorbed?

A

Jejunum and ileum

126
Q

What is the active form of pyridoxine (B6)?

A

Pyridoxyl phosphate

127
Q

What is the function of pyridoxyl phosphate?

A

Coenzyme involved in:

  1. Amino acid degradation: aminotransferases, decarboxylases, serine hydroxymethyltransferase, aldolase
  2. Glycogen degradation: glycogen phosphorylase
  3. Porphyrin synthesis
128
Q

Dietary sources of pyridoxine (B6)

A 
Beans, nuts, leugmes
Meats
Eggs
Fish 
Whole grains and fortified grains and cereals
129
Q

Who gets pyridoxine (B6) deficiency?

A

Alcoholics
People with kidney failure
People on Isoniazid for tuberculosis

130
Q

What are the sx of pyridoxine deficiency?

A

Cheilosis: scaling at the corners of the mouth
Angular stomatitis: inflammation at mouth corners
Glossitis: inflammation of the tongue
Dematitis
Peripheral neuropathy
Microcytic hypochromic anemia
Confusion and irritability

131
Q

What is the toxicity of pyridoxine (B6)?

A

Peripheral sensory neuropathy

132
Q

What are the two hematopoietic/1C metabolism vitamins?

A

Folate (B9)

Cobalamin(B12)

133
Q

Where is folate (B9) absorbed?

A

Duodenum
Jejunum **
Ileum

134
Q

What is the active form of folate (B9)?

A

Tetrahydrofolate

135
Q

What is the function of folate (B9)

A

Carrier of 1C units for:

  1. Purine synthesis
  2. dTMP synthesis
  3. Conversion of homocysteine to methionine for S-adenocylmethionine synthesis
136
Q

Dietary sources of folate?

A 
Beans and legumes
Citrus fruits
Dark, leafy green vegetables 
Fortified grain and cereals
Meat
137
Q

What are the 2 main causes of folate deficiency?

A 
Inadequate intake
Antifolate treatment (methotrexate, 5-flurouracil)
138
Q

What are the main sx of folate deficiency?

A

Megaloblastic anemia
Leukopenia
Fetal neural tube defects
Glossitis

139
Q

What are the sx of spina bifida occulta, a neural tube defect that can occur with inadequate maternal folate intake?

A

Pain
Weakenss
Numbness in the legs and back

140
Q

What is anencephaly?

A

Missing parts of the brain

141
Q

How much supplementation of folate does the USPHS recommend?

A

400 ug dose daily

142
Q

How is vitamin B12 (cobalamin) absorbed?

A

IF-B12 complex in the ileum

143
Q

Storage of cobalamin (B12)

A

Liver

Storage lasts around 2 years

144
Q

What are the only 2 biochemical rxns that require B12?

A

Methionine synthase

Methyl malonyl-conenzyme A mutase

145
Q

What are good sources of B12?

A 
Meat 
Shellfish
Fish
Eggs
Milk and yogurt and cheese
**NOT PLANT PRODUCTS
146
Q

What are some causes of vitamin B12 deficiency?

A
  1. Impaired absorption: IF deficiency or ilieal resection
  2. Increased requirement
  3. Decreased intake (vegan)
  4. Tapeworm (Diphyllobothrium)
147
Q

What are the clinical s/s of B12 deficiency? (3)

A
  1. Megaloblastic anemia (pernicious anemia)
  2. Neural tube defects
  3. Subacute combined neural degeneration: dorsal and lateral tract demyelination, parasthesias, spastic paraparesis, sensory ataxia
148
Q

What are the three antioxidant vitamins?

A

Vitamin C
Vitamin E
Beta carotene (provitamin A)

149
Q

What are the post-translational modificaiton vitamins?

A

Vitamin C

Vitamin K

150
Q

Where is ascorbate absorbed?

A

Jejunum and ileum

151
Q

What are the functions of ascorbate (vitamin C)

A

Antioxidant: reduces ROS
Cofactor of enzymes that reduce metal ions
Post-translational modification of proteins (collagens), lysyl and proyl hydroxylase
Synthesis of neurotransmitters and hormones

152
Q

What are sources of ascorbic acid?

A

Fruits and vegetables

Highest in citrus fruits, strawberries, green peppers, broccoli, green leafy vegetables, tomatoes, potatoes

153
Q

What happens with vitamin C defiency?

A

SCURVY
Impaired collagen formation: poor vessel support results in bleeding tendency, impaired wound healing, easy bruising, corkscrew hairs, and petechial hemorrhage

154
Q

What are the fat-soluble vitamins?

A 
Vitamin A (Retinol, Carotenes)
Vitamin D (Cholecalciferol)
Vitamin E (Tocopherols)
Vitamin K (Phylloquinones)
155
Q

Where are fat soluble vitamins absorbed?

A

Duodenum

Jejunum

156
Q

Where is vitamin D absorbed?

A

Duodenum and jejunum

ALSO the ileum

157
Q

Where is vitamin K produced in the body?

A

Produced by microbiota in the large intestine

158
Q

What vitamin is tocopherol?

A

Vitamin E

159
Q

What is the most active form of vitamin E?

A

alpha-tocopherol

160
Q

How is tocopherol (vitE) absorbed?

A

From micelles in the duo and jej

161
Q

How is vitE, or tocopherol distributed in the body?

A

Chylomicrons

162
Q

Where is tocopherol (vitE) stored?

A

Adipose tissue
Liver
Muscle

163
Q

What is the function of vitamin E/tocopherol?

A

Antioxidant–scavengers free radicals

164
Q

What are dietary sources of vitaminE/tocopherol?

A

Vegetable oils
Liver
Eggs

165
Q

Incidence of vitamin E / tocopherol deficiency?

A

Uncommon, except for with malabsorption syndromes, TPN, and premature infants

166
Q

What are the sx of tocopherol/vit E deficiency

A

Irritability
Edema
Hemolytic anemia

167
Q

What is a pharmacological use of tocopherol/vitamin E

A

Alzheimer’s disease progression inhibitor

168
Q

What vitamin is phylloquinones?

A

Vitamin K

169
Q

How is vitamin K absorbed?

A

From micelles into the duo, jej, ileum

170
Q

How is vitamin K distributed in the body?

A

Chylomicrons

171
Q

Where is vitamin K stored?

A

Liver

172
Q

What is the active form of vitamin K?

A

Vitamin K1

173
Q

What are the functions of vitamin K?

A
  • Cofactor for vit K dependent gamma carboxylase (needed for factors II, VII, IX, X, S, C)
  • -> modified Gla residue binds Ca and localizes coagulation proteins on activated platelets
174
Q

What are the dietary sources of vitamin K?

A

Green vegetables, spinach, kale
Peas
Cauliflower and cabbage
Synthesized by bacteria in the intestine

175
Q

Though vitamin K deficiency is rare, what can cause it?

A 
Warfarin tx
Malabsorption syndromes 
Broad spectrum antibiotics (kills flora)
Lack of gut flora in neonates 
Chronic liver disease
176
Q

What are the sx of vitamin K deficiency?

A

Bleeding–defective clotting

  • > Easy bruising and hematomas
  • > Hemorrhagic disease of the newborn
177
Q

What is seen in vitamin K toxicity?

A

Shortened bleeding time

**no toxicity with food as a source of the vitK

178
Q

What vitamin are cerotenes and retinoids?

A

Vitamin A

179
Q

Where is vitamin A stored?

A 
Liver stellate (ito) cells
Retinyl esters
180
Q

What is the function of beta carotene?

A

Antioxidant

Vitamin A precursor

181
Q

What is the major transport form of vitamin A?

A

Retinol

182
Q

What form of vitamin A is important for vision?

A

11-cis retinal (retinaldehyde)

183
Q

What form of vitamin A is involved in the regulation of retinoid responsive gene expression–epithelilal cells function, mucous cell function, immunity, reproduction

A

Retinoic acid (all-trans, 9-cis)

184
Q

How is 11-cis-retinal involved in vision?

A

Binds rhodopsin in rods and to cone pigments in cones: difference in binding to the three cone pigments results in absorption of different wavelengths of light
Light converts 11-cis retinal to all-trans-retinal

185
Q

What happens with the conversion of 11-cis to all-trans retinal by light?

A
  • The GPCR transducin in the rod and cone membranes changes conformation and activates the G-protein, activating a phosphodiesterase
  • Cleavage of cGMP closes cGMP coupled ion channel, signal to brain
186
Q

What are good sources of beta carotene?

A

Green leafy vegetables

Intensely colored vegetables like carrots, sweet potatoes, and red peppers

187
Q

What are good sources of rentinyl esters?

A

Eggs
Meat
Dairy products

188
Q

When is vitamin A deficiency seen in the US?

A

Poor intake with serious viral infections
Malabsorption syndromes
Liver cirrhosis

189
Q

What is the clinical presentation of vitamin A deficiency?

A

Impaired vision–night blindness
Squamous metaplasia–mucus and epithelial cells
Renal, urinary calculi
Predisposition to pulmonary infections, diarrhea

190
Q

What are some of the consquences of squamous metaplasia with retinoic acid deficinecy?

A

Xerophthalmia, Xerosis
Bitot’s spots (keritin debris)
Corneal ulceration, keratomalacia
FOllicular hyperheratitis

191
Q

Toxicity of beta carotene?

A

Non-toxic, but yellow skin due to fat deposition

**sclera not yellow

192
Q

Toxicity of retinol

A

Toxic at high levels: blurred vision, abdominal pain, peeling of the skin, hair loss, headache, dizziness, vomiting, bone pain and deformities
Death if levels are high enough

193
Q

Toxicity of retinal?

A

Toxic at high levels, esp to the retina

194
Q

Toxicity of retinoic acid

A

Toxic at levels used to treat acne: teratogenic and peeling of the skin

195
Q

What vitamin is calciferol?

A

Vitamin D

196
Q

What are the two dietary forms of vitamin D?

A

Animals: D3, cholecalciferol
Plants: D2, ergocalciferol

197
Q

What form of vitamin D can be synthesized in the skin

A

D2

198
Q

What is the active form of vitamin D?

A

1,25 dihydrovitamin D (cholecalciferal)

199
Q

Absorption of vitamin D?

A

Micelles to epithelial cells

Duodenum, jejunum, ileum

200
Q

Where is vitamin D stored?

A

Liver

201
Q

WHat is the function of vitamin D?

A

Controls the expression of vitamin D responsive genes
Maintains normal calcium and phosphate levels
Controls: cell cycle arrest, apoptosis, immune suppression, anti-inf, differentiation

202
Q

What is the effect of vitamin D when calcium or phosphate is low

A

Increases absorption in the intestines
Decreases excretion by the kidney
Increases release by the bones

203
Q

Sources of vitamin D/calciferols

A 
Cheese
Butter and margarine 
Fortified milk
Fish
Fortified cereals 
**sunlight
204
Q

What causes vitamin D deficiency?

A 
Inadequate sunlight/dietary deficiency 
Decreases absorption
Metabolic errors 
End organ resistance
Phosphate depletion
205
Q

What is the result of vitamin D deficiency in children

A

Rickets:

  • bowed legs
  • frontal bossing
  • pigeon breast
206
Q

What is the result of vitamin D deficiency in adults

A

Osteomalcia:

  • soft, painful, bendable
  • osteoporosis: loss of bone density, fragile bone
  • Dowager’s humb
207
Q

What are s/s of vitamin D toxicity?

A 
Diarrhea
Dermatitis
Headache
Nausea 
Anorexia
Calcification of soft tissue
Decalcificaiton of bones 
Kidney stones
208
Q

Where are ions absorbed?

A

Stomach

Entire intestine

209
Q

What form is iron absorbed in?

A

Fe2+

210
Q

How is iron stored?

A

Ferritin and hemosiderin

In the liver, spleen, and bone marrow

211
Q

Sources of iron

A 
Meats 
Fish
Shellfish
Lentils
Beans
Seeds 
Tofu
Spinach
212
Q

Function of iron

A

In heme as part of hemoglobin or myoglobin
Iron sulfer complexes in the TCA cycle, ETC
Enzyme cofactor

213
Q

What is the most common nutritional deficiency?

A

Iron deficiency

214
Q

Causes of iron deficiency

A

Inadequate diet, milk fed infants
Impaired absorption
Blood loss–GI and menstrual

215
Q

What are the sx of iron defiicency?

A

Hypochromic, microcytic anemia
Impaired cognition and work capacity
Immune deficiency

216
Q

What is the toxicity of iron?

A

Hemochromatosis

Abnormal deposition in the liver, pancreas, heart, and skin

217
Q

Where is zinc absorbed?

A

Jejunum

218
Q

What are sources of zinc?

A

Oysters and other shellfish
Meat
Plants

219
Q

What are the functions of zinc

A

Component of enzymes involved in metabolism (oxidases, metalloproteinases)
Gene expression–Zn finger protein
Spermatogenesis
Skin maintenance and wound healing

220
Q

Though incidence of zinc deficiency is rare, in what cases is it relatively common?

A 
Diabetes mellitus
Malabsorption syndromes and chronic diarrhea
Renal disease and dialysis
IV feeding 
Major burn patients 
Inborn error of zinc absorption
221
Q

What are the sx of zinc deficiency?

A

Rash
Anorexia
Diarrhea
Growth retardation
Depressed wound healing and immune response
Infertility due to inhibition of testosterone syn

222
Q

What happens in zinc toxicity?

A

Inhibits copper absorption, leading to a copper deficiency

223
Q

Where is iodine absorbed?

A

Stomach

224
Q

What are sources of iodine?

A

Salt water fish and shellfish

Iodized NaCl

225
Q

What is the main function of iodine?

A

Component of thyroid hormones

226
Q

What are the sx of iodine deficiency?

A

Goiter
Cretinism: children with dwarfism, retardation, bone deformation, subnormal BMR)
Myxedema: adults with dry skin, swelling of the skin around nose and lips, mental deterioration, subnormal BMR

227
Q

What ate sx of iodine tox?

A

Goiter

Thyrotoxicosis

228
Q

Where is copper absorbed?

A

Stomach

Duodenum

229
Q

What are the sources of copper?

A 
Liver
Shellfish
Chocolate
Nuts
Seeds
230
Q

Functions of copper

A
  1. Oxidation rxns including e- transport: cyt C oxidase, tyrosinase
  2. Neurotransmitter reg: dopamine beta oxidase
  3. Antioxidants: superoxide dismutase
  4. Collagen crosslinking enzymes: lysyl oxidase
  5. Development of vascular and skeleton structures and the CNS
231
Q

Though copper deficiency is rare, when do you see it?

A

Malnutrition
Excess zinc intake
Dialysis patients
Genetic diseases like Menke’s syndrome

232
Q

What are the sx of copper def?

A 
Microcytic hypochromic anemia
Muscle weakness
Neurologic defects 
Abnormal collagen crosslinks leading to bleeding
Neutropenia
233
Q

When do you get copper toxicity?

A

Genetic disease–WD

234
Q

What are the sx of copper tox?

A

Neurological defects

Kaiser Fleischer rings

235
Q

Where is fluoride absorbed?

A

Stomach

236
Q

What are the sources of fluoride?

A

Water (natural or supplemented)

Toothpaste

237
Q

Functions of fluoride

A

Required by teeth

238
Q

What happens with fluoride deficiency?

A

Dental caries

239
Q

When does fluorine tox occur?

A

Kids eating fluorinated toothpaste

240
Q

What are the sx of fluoride tox?

A

Mottled tooth enamel

241
Q

Where is selenium absorbed?

A

Duo

242
Q

Sources of selenium

A

Plants grown in selenium containing soil

Fish and shellfish

243
Q

What are the functions of selenium

A

Component of glutathione peroxidase
Antioxidant with vitamin E
Regulates thyroid hormone action

244
Q

Effects of selenium def

A

Myopathy

Cardiomyopathy (kids)

245
Q

Selenium tox

A 
Hair and hail damage
Tooth decay
Neuropathy
Liver cirrhosis 
Depression
246
Q

Name the ion:

  1. oxygen transport and e metabolism
  2. wound healing, spermatogenesis
  3. antiox, e transport, collagen x linking, devo
  4. dental health
  5. antiox, thyroid hormone function
A
  1. iron
  2. zinc
  3. iodine
  4. copper
  5. fluoride
  6. selenium

GI (28 decks)

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