Exam 1: Water Soluble Vitamins Flashcards
1
Q
Water soluble vitamins
A
Folate Riboflavin Niacin Thiamin B6 B12 Pantothenic acid Biotin Vitamin C
2
Q
T/F Water soluble vitamins are not significantly lost during cooking, are stored in large quantities, and are not transported by carriers from diet and supplements
A
FALSE.
- WSV are significantly lost during cooking
- Are stored in very little quantities
- Are transported by carriers
3
Q
Dietary water soluble vitamins are absorbed by __________ while supplement water soluble vitamins are absorbed by __________
A
Dietary = facilitated diffusion Supplements = passive diffusion
4
Q
What B complex vitamins are known for releasing energy?
A
Thiamin Riboflavin Pantothenic acid Biotin B6
5
Q
What B complex vitamins are known for influencing hematopoietic cells?
A
Folate
B12
B6
Pantothenic acid
6
Q
This water soluble is nonessential for most animals and plants, but is essential for humans, primates, fruit bats, and guinea pigs. Also known as ascorbic acid
A
Vitamin C
7
Q
Functions of Vitamin C
A
1) Antioxidant (regenerates vitamin E)
2) Coenzyme (helps iron and copper enzymes hydroxylate to make collagen, carnitine, and Nt’s)
3) Absorption of nonheme iron (from plants and supplements)
8
Q
Sources of vitamin C
A
Peppers
Citrus fruits and fruit juices
Broccoli
Dark green leafy veggies
9
Q
Vitamin C RDA’s for men, women, and smokers (both men and women)
A
Men = 90 mg
Women = 75 mg
Men (+35 for Smoking)= 125 mg
Women (+35 for Smoking) = 110 mg
10
Q
What effects does cooking have on Vitamin C?
A
- Easily extracted in water
- Easily oxidized
11
Q
T/F Frozen fruits and vegetables contain more vitamin C than fresh fruits and vegetables that have been shipped a far distance
A
True
12
Q
Vitamin C Deficiency name
A
Scurvy
13
Q
4 H’s of Scurvy (Vitamin C Deficiency)
A
1) Hemorrhagic signs (poor wound healing)
2) Hyperkeratosis of hair follicles
3) Hypochondriasis (psychological problems)
4) Hematologic (impaired collagen synthesis and decreased iron absorption)
14
Q
People who may suffer vitamin C toxicity or have problems associated with it
A
1) Kidney disease = increased risk of kidney stones
2) Impaired iron metabolism leading to iron toxicity (vitamin C helps with nonheme iron absorption)
15
Q
B1
A
Thiamin
16
Q
Function of TDP
A
TDP = Coenzyme form of Thiamin
- Energy production (pyruvate to acetyl CoA)
- NADPH and pentose synthesis
17
Q
What enzymes are associated with TDP?
A
- Dehydrogenases (use TDP to make acetyl CoA from pyruvate)
- Transketolases (TDP found within the enzyme to help make NADPH and pentose synthesis)
18
Q
Function of TTP
A
TTP= Noncoenzyme form of Thiamin
-Regulates Na+ channels and Cl- transport in nerve conduction (Nervous system associated)
19
Q
Primary source of Thiamin
A
Pork
20
Q
What destroys thiamin?
A
Thiaminases Sulfites Heat Oxidation Light
21
Q
Specific symptom associated with early thiamin deficiency
A
Tender calf muscles
22
Q
Major targets of thiamin deficiency
A
Peripheral nerves
Heart
Brain
23
Q
Thiamin deficiency associated with alcoholics
A
Wernicke-Korsakoff syndrome
24
Q
Chronic adult thiamin deficiency.
A
Wet beriberi
25
Chronic infant thiamin deficiency
Acute beriberi
26
Chronic geriatric thiamin deficiency
Dry beriberi
27
T/F Multiple heart problems, peripheral edema, tense calf muscles, high blood pressure, and peripheral neuropathy are all associated with Dry beriberi
FALSE.
| These are all associated with Wet beriberi (Dry = muscle weakness, extremity wasting, peripheral neuropathy)
28
Who is at risk for a thiamin deficiency in the U.S.?
- Elderly (impaired absorption and dietary deficiency)
- Alcoholics (impaired absorption and dietary deficiency)
- Babies (dietary deficiency)
- Patients with malabsorptive conditions like Crohn's, celiac disease, CF, etc. impaired absorption)
29
Tolerable upper intake of Thiamin
None (toxicity is rare)
30
B2
Riboflavin
31
Coenzymes that contain a riboflavin ring. Found in ETS, coenzymes for dehydrogenases, 1st step of beta-oxidation, and Krebs cycle.
FAD and FMN
32
FAD and FMN are used for the synthesis of ______ and _____
Niacin
| B6
33
___ mg of tryptophan = ___ mg of niacin
60 mg of tryptophan = 1 mg of niacin
34
Sources of riboflavin
```
Dairy
Dark green vegetables
Whole grains
Eggs
Meats
Fortified cerals
```
35
T/F Riboflavin is destroyed by cooking, but stable with UV light and alkaline pH
FALSE.
| Riboflavin is stable during cooking, but destroyed by UV light and alkaline pH
36
Name for a riboflavin deficiency
Ariboflavinosis
37
Symptom that arises from ariboflavinosis. Presents as lesions in the corner of the mouth
Cheilosis
38
Symptom that arises from ariboflavinosis. Presents as cracks at the corner of the mouth
Angular stomatitis
39
Symptoms that arise from ariboflavinosis. Presents as swelling and a bright red surface of the tongue
Glossitis (swelling) and magenta tongue (red tongue)
40
T/F Ariboflavinosis is seldom present by itself. It normally is found with other B vitamin deficiencies
True
41
Severe riboflavin deficiency inhibits ________ and ______ synthesis
B6
| NAD
42
Who is at risk for developing a riboflavin deficiency?
- Alcoholics
- People in developing nations
- Diabetics (enhanced riboflavin excretion)
- Patients with thyroid disorders (altered metabolism)
- Tricylic antidepressants decrease riboflavin absorption
43
What has been shown to be an effective dose for treating migraines?
Riboflavin
44
T/F Riboflavin has no tolerable upper intake set
True
45
B3
Niacin
46
60 mg of this amino acid is required to make 1 mg of niacin
Tryptophan
47
Cofactor required for NAD/NADP synthesis
Iron
48
Function of niacin
Coenzymes for >200 enzymes
49
Niacin derivatives are coenzymes for mostly this type of enzyme
Dehydrogenases
50
Niacin derivative. Used in glycolysis, Krebs cycle, Beta-oxidation, and ethanol metabolism
NAD
51
Niacin derivative. Used in fatty acid synthesis, cholesterol synthesis, and folate synthesis
NADP
52
In OHOT (beta-oxidation), what B vitamins are used?
1st O = Riboflavin (makes FADH2)
| 2nd O = Niacin (makes NADH)
53
T/F The average american consumes 900 mg of tryptophan daily, providing 15 mg NE
True
54
Sources of niacin
Meats, peanuts, yeast, enriched cereals
55
Niacin deficiency
Pellagra (Rough + Skin)
56
4 D's of Pellagra
1) Dermatitis (sunburn on face, neck, and extremities)
2) Dementia (headache, memory loss, delirium)
3) Diarrhea (glossitis, cheilosis, stomatitis)
4) Death (very rare)
57
What 2 B vitamin deficiencies are usually found together?
Pellagra (Niacin)
| Ariboflavinosis (Riboflavin)
58
B5
Pantothenic acid
59
Pantothenic acid is part of _____ and _____
```
Coenzyme A (CoA)
Acyl-Carrier Protein (ACP)
```
60
Functions of pantothenic acid
Coenzyme
+Metabolism of carbs, lipids, proteins
+Synthesis of fatty acids, cholesterol, bile acids, and steroid hormones
+Posttranslational acetylation of proteins)
61
Sources of pantothenic acid
Found almost everywhere in many foods
62
Pantothenic acid deficiency
Burning Feet Syndrome
63
T/F Burning Feet Syndrome is prevalent in people over 40 with a European-Caucasian ancestry.
Burning Feet Syndrome is very rare
64
Why do people with Burning Feet Syndrome feel fatigued or weak?
BFS = Pantothenic acid deficiency
Makes low Coenzyme A which means the body can't make adequate ATP causing lethargy
65
T/F There is no toxicity reported with Pantothenic acid
True
66
B7
Biotin
67
Functions of Biotin
-Noncoenzyme
+Transcription of several enzymes
-Coenzyme
+Bound to several carboxylases
68
How does biotin affect fatty acid synthesis?
Biotin is associated with Acetyl CoA Carboxylase turning acetyl CoA into malonyl CoA (committed step in Fatty acid synthesis)
69
T/F Eating raw eggs is an excellent source of Biotin
FALSE.
| Raw eggs contain a biotin chelator, preventing absorption. Properly cooking the eggs will help with absorption of biotin
70
Major symptom associated with a Biotin deficiency
Hypercholesterolemia
71
T/F Biotin deficiency is so common that 50-80% of pregnant women have it, leading to possible birth defects or abnormal metabolism.
FALSE.
50-80% of pregnant women have a MARGINAL biotin deficiency that can cause birth defects. Biotin deficiency over all is rare
72
T/F There is no toxicity associated with biotin
True
73
Functions of B6
Coenzyme (PLP)
+Used by >100 enzymes
+Required for amino acid and glycogen metabolism
+Needed for synthesis of heme, sphingolipids in myelin sheath, steroids, niacin, and Neurotransmitters, and histidine
74
What neurotransmitters are made from vitamin B6?
Serotonin
Epinephrine
Norepinephrine
GABA (made from glutamate)
75
T/F Vitamin B6 has a higher availability from plants than animals
FALSE.
| B6 has higher availability from animal than plants (easier to utilize from animals than plants)
76
Major symptom associated with a vitamin B6 deficiency
Peripheral neuropathy
77
Why does a B6 deficiency cause peripheral neuropathy?
B6 is required to make sphingolipids in the myelin sheath of nerves. Low B6 means its harder to make the myelin which decreases nerve transduction.
78
Who is most at risk for a vitamin B6 deficiency?
- Patients taking corticosteroids, anticonvulsants, penicillin, and isoniazid(TB medication)
- Celiac disease
- Renal dialysis
79
B9
Folate (Pteroylmonoglutamic acid)
80
Reduced form of B9 in supplements
Folic acid
81
T/F Folic acid need to be digested to be absorbed
FALSE.
| Folic acid from supplements is in the reduced form so it does not need to be digested to be absorbed
82
Folate contains many _____________ residues which are removed by _________ in the brush border
Glutamic acid
| Conjugase
83
What are common conjugase inhibitors?
Legumes
Oranges
Cabbage
Chronic alcohol consumption?
84
80% of folate is absorbed in the ______ and reduced via _______
Small intestine
| Enterocytes
85
Reduced form of folate that travels from the small intestine to the liver
THF (Tetrahydrofolate)
86
From the liver, THF is bound to _________ in the plasma
Folate Binding Protein
87
T/F Almost all of the THF in the blood is eventually stored in the liver.
FALSE
50% = stored in the liver
Remaining = found in cytoplasm and mitochondria of cells (important for DNA and RNA synthesis)
88
What ion is required by conjugase to function?
Zinc
89
What other B vitamin is required to make THF?
Niacin
90
Function of folate
Coenzyme
+ Donor and acceptor in 1 carbon metabolism
+ DNA synthesis and repair
+ Formation of RBC and WBC
+ AA metabolism (histidine to glutamate and homocysteine to methionine)
91
What B vitamin besides folate allows the amino acid metabolism of homocysteine to methionine?
B12 (Cobalamin)
92
How does a cobalamin deficiency affect the breakdown of THF?
THF cannot be regenerated and folate is trapped as 5-methyl THF
93
What name is given to the fact that a cobalamin deficiency prevents THF from being regenerated and trapping it as 5-methyl THF?
Methyl-Folate Trap
94
Best source of folate. Is folate lost during cooking?
Dark green leafy vegetables
| 50-90% of folate is lost during cooking
95
T/F Folate is 1 of 5 vitamins required by law to be added to foods
FALSE.
| Folate is the only vitamin required by law to be added to foods
96
Folate deficiency causes this condition
Megaloblastic Macrocytic Anemia
97
Folate deficiency is associated with ______ defects like ________ and ________
Neural tube defects
Spina bifida
Anencephaly
98
T/F Folate supplementation can prevent 95% of all neural tube defects
FALSE.
| Prevents 70% of NTD
99
T/F Folic acid does increase a persons risk of developing cancer
True
| RR = 1.07 overall and 1.24 for Prostate cancer
100
What polymorphisms are present in the mutated C677T methylenetetrahydrofolate reductase gene?
MTHFR gene
CC (normal) = 100% activity
CT (mutant) = 65% activity
TT (mutant) = 30% activity
101
T/F A MTHFR gene mutation is present in 30-40% of Pacific islanders and 40% of ADHD patients
FALSE.
| MTHFR mutation is present in 5-10% of Caucasians and 16% of autistic patients
102
Patients with the 677TT (homozygous mutation) polymorphism have an increased risk of what?
- Cancer (Breast = 180%; Esophageal = 163%)
- Migraines (37%)
- Heart disease (higher levels of LDL oxidation)
- Infertility and miscarriages
- Fracture risk (23%)
103
High doses of folate can mask a _________________ and/or bind with ____ in the GI tract causing a deficiency
B12 deficiency
| Zinc
104
B12
Cobalamin
105
What are the several forms of B12 that our bodies can form into an active coenzyme?
- Cyanocobalamin (CN)
- Hydroxocobalamin (OH)
- Hydrocobalamin (H2O)
- Nitrocobalamin (NO2)
106
Active coenzymes of B12
1) 5-deoxyadenosylcobalamin (5-deoxyadenosyl)
| 2) Methylcobalamin (CH3)
107
Most common form of B12 in supplements
Cyanocobalamin
108
Enzyme that breaks the B12-protein bond in the stomach
Pepsin
109
_________ secreted from the _________ in the stomach required to absorb B12
Intrinsic factor (IF)
110
________ secreted from the saliva and stomach. Bonds to B12 in the stomach before being removed and allowing IF to attach to the B12
R protein
111
Enzyme that removes R protein from B12 in the small intestine
Proteases
112
The IF receptor in the _____ binds the B12-IF complex and absorbs it by _____________
Ileum
| Receptor-Mediated Endocytosis
113
How would omeprazole causing a B12 deficiency?
PPI's like omeprazole decrease IF secretion, which prevents the formation of the IF-B12 complex, not allowing absorption of B12 in the ileum
114
Conditions that can decrease B12 digestion and absorption
- Zollinger-Ellison syndrome (too much HCl)
- Medications for GERD (low HCl)
- Pancreatic insufficiency (low proteases; can't release B12 from R proteins)
- Malabsorptive syndromes (Celiac's, Crohn's, IBS, CF, etc.)
115
T/F 85% of B12 is absorbed in the jejunum and released into the enterocytes
FALSE.
| ~50% is absorbed in the ileum and B12 is released into the enterocytes
116
Once in the enterocyte, B12 is bond to ______ in the blood and sent to the ______
Transcobalamins
| Liver
117
Where is B12 stored in the body?
- Liver (50%)
- Bone
- Brain
- Muscles
118
Functions of B12
Coenzyme (methylcobalamin)
-Myelination
Coenzyme (adenosylcobalamin)
-Metabolism of odd chain fatty acids and amino acids
119
What amino acids are metabolized using the coenzyme adenosylcobalamin (B12)?
Threonine
| Isoleucine
120
T/F 33% of B12 is lost during cooking. Meats, dairies, and fortified sources are some of the best sources of B12
True
121
B12 deficiency can cause this condition due to decreased DNA synthesis
Megaloblastic Macrocytic Anemia (like a folate deficiency)
122
T/F With megaloblastic macrocytic anemia, supplementation of folate can help get rid of hematologic symptoms, but not neurologic symptoms due to demyleination of nerves from a possible B12 deficiency covered up by the folate deficiency
True
123
Main symptom of a B12 deficiency
Peripheral neuropathy
124
Type of megaloblastic anemia where antibodies attack gastric parieral and mucosal cells causing a decrease in HCL secretion and B12 absorption.
Pernicious anemia
125
T/F There is no one treatment for pernicious anemia
FALSE.
| B12 injections can be used to treat pernicious anemia
126
Why would a strict vegan not develop B12 deficiency symptoms for 5-10 years after starting their diet?
B12 is stored throughout the whole body (50% in the liver) so we have enough in our bodies to live off of for years
127
T/F Most B12 deficiencies are due to inadequate intake instead of inadequate absorption
FALSE.
| Inadequate absorption is more likely to cause B12 deficiency than inadequate intake
128
Who is at risk for developing a B12 deficiency?
- Strict vegetarians/vegans
- Elderly
- Zollinger-Ellison Syndrome (too much HCl)
- Pernicious anemia (AIC- parietal cell attack)
- Gastritis (impaired IF release)
- Achlorhydria (lack of HCl)
- Malabsorptive conditions
- PPI's (acid reducing meds)
- Pregnant women
129
T/F There is no toxicity associated with B12
True
