1What is the coenzyme form of thiamine (B1)?
Thiamine pyrophosphate (TPP)
2In which reactions is thiamine important?
Carboxylase reactions, decarboxylase reactions, and transferase reactions
3Who are common groups that experience thiamine deficiencies?
Malnourished individuals and alcoholics
4What effect does prolonged cooking have on thiamine?
It destroys thiamine
5What happens to thiamine when boiling or blanching foods?
It leaches into the water
6How does ethanol affect thiamine absorption?
Ethanol inhibits absorption and TPP formation
7What syndrome associated with thiamine deficiency includes slurring speech?
Wernicke-Korsakoff Syndrome
8What are the two types of Beriberi and the systems they affect?
Dry (nervous system) and Wet (cardiovascular system)
9What dietary change led to thiamine deficiencies?
Switching from whole grain rice to just the kernel
10Where in the rice is thiamine primarily found?
In the husk
11Can riboflavin (B2) be destroyed by cooking?
No, riboflavin cannot be destroyed by cooking.
12What can destroy riboflavin (B2)?
UV light and irradiation.
13What is a good dietary source of riboflavin (B2)?
Milk.
14What role does riboflavin (B2) play in the body?
Riboflavin serves as a coenzyme in energy metabolism.
15What are the coenzyme forms of riboflavin (B2)?
Flavin Mononucleotide (FMN) and Flavin adenine dinucleotide (FAD).
16What issues can riboflavin (B2) deficiencies cause?
Oral, ocular, and genital problems.
17What specific conditions can result from riboflavin (B2) deficiency?
Angular cheilitis, photophobia, and scrotal dermatitis.
18What are the two chemical structures of niacin (B3)?
Nicotinic acid and Nicotinamide.
19What is the major form of niacin in the blood?
Nicotinamide.
20From what amino acid does the body manufacture niacin?
Tryptophan.
21What are the conditions for the body to manufacture niacin from tryptophan?
Protein synthesis needs must be met first.
22In which type of reactions is niacin involved?
Redox reactions.
23What are the coenzyme forms of niacin?
Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP).
24What is the deficiency disease associated with niacin?
Pellagra.
25What are the symptoms of pellagra?
Diarrhea, dermatitis, dementia, and death.
26Which vitamins and mineral are required for protein synthesis, affecting niacin levels?
Vitamin B1, B2, B6, and iron.
27What disease is not caused by a niacin deficiency but causes a niacin deficiency?
Hartnup’s Disease.
28What happens in Hartnup’s Disease regarding tryptophan?
The kidneys do not reabsorb tryptophan, leading to its excretion in urine.
29What is the condition caused by excess niacin intake?
Niacin Flush.
30What are the symptoms of Niacin Flush?
Itchy, tingly sensation that can be painful.
31What are the three forms of pyridoxine (B6)?
Pyridoxal, pyridoxine, and pyridoxamine.
32What can happen to each form of pyridoxine (B6)?
Each can be phosphorylated.
33What is the coenzyme form of pyridoxine (B6)?
Pyridoxal phosphate (PLP).
34In what types of reactions is PLP involved?
Amino acid metabolism, including transamination and deamination reactions.
35What role does pyridoxine (B6) play in glycogen metabolism?
PLP is involved in glycogen metabolism.
36What conversions does pyridoxine (B6) facilitate?
Conversion of tryptophan to niacin or serotonin.
37What other syntheses is pyridoxine (B6) involved in?
Synthesis of heme, nucleic acids, and lipids.
38How common is dietary deficiency of pyridoxine (B6)?
Dietary deficiency is rare.
39What can increase the need for pyridoxine (B6)?
High protein intake.
40What are some symptoms of pyridoxine (B6) deficiency?
Depression, irritability, and confusion.
41What can hinder the absorption of pyridoxine (B6)?
Alcohol and isoniazid (medication to treat TB).
42What can excess intake of pyridoxine (B6) cause?
Irreversible nerve degeneration and destruction of dorsal root ganglia.
43What is the role of biotin (B7) as a coenzyme?
Biotin carries activated carbon dioxide in carboxylase reactions.
44In which cycle is biotin critical?
The TCA cycle.
45In which processes does biotin participate?
Gluconeogenesis and fatty acid synthesis.
46Which amino acids' synthesis involves biotin?
Isoleucine and valine.
47How common is biotin deficiency?
Biotin deficiency is rare.
48Why is biotin deficiency rare?
Gut bacteria produce half of the biotin needed.
49How can one induce a biotin deficiency?
By eating 2 raw egg whites daily for several months.
50Why do raw egg whites affect biotin absorption?
They contain a protein that binds biotin and prevents its absorption.
51Who produces biotin in the body?
GI bacteria produce biotin.
52Is there any trouble with excess biotin intake?
No, there is no trouble with excess biotin intake.
53What is another name for folate (B9)?
Folic acid.
54What are the active forms of folate?
Dihydrofolate and tetrahydrofolate.
55What is the role of folate in metabolism?
Transfers single-carbon compounds during metabolism.
56How does folate interact with vitamin B12?
Converts vitamin B12 to its active coenzyme form.
57What is folate's role in DNA?
Synthesizes and repairs DNA.
58Why is folate important for cell division and growth?
Aids in rapid cell division and growth.
59What developmental problem can folate deficiency cause?
Neural tube defects (e.g., spina bifida) in developing fetuses.
60When should folate supplements be taken to prevent neural tube defects?
One month before conception and through the first trimester.
61How has the US government helped prevent folate deficiency?
By fortifying grain products.
62What is a safety concern with folate fortification?
It does not cause but may mask a vitamin B12 deficiency.
63How do vitamin B12 and folate interact?
They depend on each other for activation.
64What type of cells need a lot of B12?
Cells that are rapidly turning over.
65How is B12 released from proteins in the stomach?
Stomach hydrochloric acid releases B12 from proteins.
66What helps absorb B12 in the small intestine?
Intrinsic factor binds to B12 and helps absorb it.
67What is the only source of B12?
Animals.
68What biological molecules does B12 help synthesize?
Nucleotides, DNA, RNA, and fatty acids.
69What are some roles of B12 in the body?
Regeneration of methionine and synthesis of fatty acids, DNA, and RNA.
70What is pernicious anemia?
Anemia caused by inadequate absorption of B12.
71What can cause inadequate absorption of B12?
Lack of hydrochloric acid or intrinsic factor, vegan diets, excessive alcohol intake, tapeworms, and inability to produce enough stomach acid.
72How long can the body recycle B12 before a deficiency occurs?
6-7 years.
73What can mask a B12 deficiency?
Folate supplementation.
74How does excessive alcohol intake affect B12 absorption?
It prevents intrinsic factor from binding to B12.
75What parasite can consume B12 before the body can absorb it?
Tapeworms.
76How do vitamin B12 and folate depend on each other?
They depend on each other for activation.
77Which cells require a lot of B12?
Cells that are turning over a lot.
78How is B12 released from proteins in the stomach?
Stomach hydrochloric acid releases B12 from proteins.
79What role does intrinsic factor play in B12 absorption?
Intrinsic factor binds to B12 and helps absorb it in the small intestine.
80What is the only dietary source of B12?
Animals.
81What biological processes does B12 help with?
B12 helps make nucleotides, regenerate methionine, and synthesize fatty acids, DNA, and RNA.
82What is pernicious anemia?
Anemia caused by inadequate absorption of B12.
83What factors can lead to inadequate absorption of B12?
Lack of hydrochloric acid or intrinsic factor, vegan diets, and excessive alcohol intake.
84How long does it take for a B12 deficiency to develop due to recycling?
6-7 years.
85What can mask a B12 deficiency?
Folate supplementation.
86How does excessive alcohol intake affect B12 absorption?
It prevents intrinsic factor from binding to B12.
87What parasitic condition can lead to B12 deficiency?
Tapeworms that consume B12 before it can be absorbed.
88What digestive issue could lead to B12 deficiency?
Inability to produce enough hydrochloric acid in the stomach.
89What was the first fat-soluble vitamin recognized?
Vitamin A.
90What is the precursor form of vitamin A that comes from plants?
Beta-carotene.
91What are the three different forms of vitamin A (retinoids)?
Retinol, retinal, and retinoic acid.
92How is vitamin A absorbed in the body?
It enters the lymphatic system, similar to fats.
93What transport protein carries vitamin A in the blood?
Retinol-binding protein (RBP).
94What role does retinal play in vision?
It helps maintain the crystal clear window of the cornea and is involved in the formation of rhodopsin for vision.
95How does rhodopsin function in vision?
Opsin and retinal combine to form rhodopsin; in the cis form it stops opsin, and in the trans form, it gets kicked out, allowing opsin to send signals to the brain.
96What is the role of retinoic acid in the body?
It regulates growth by influencing protein synthesis, cell differentiation, and functions as a transcription factor in the nucleus.
97How does retinoic acid affect epithelial cells?
It helps protect the skin from sunlight and maintains the integrity of mucous membranes.
98What are the functions of retinol in the body?
Supports reproduction, sperm development, normal fetal development, growth of children, and bone remodeling.
99What role does vitamin A play in bone health?
Vitamin A helps in bone remodeling but excessive vitamin A can interfere with vitamin D and contribute to osteoporosis.
100What are some symptoms of vitamin A deficiency?
Night blindness and blindness (xerophthalmia).
101What is xerophthalmia?
Blindness caused by a lack of vitamin A at the cornea.
102How long can vitamin A be stored in the liver?
1-2 years worth, approximately 90%.
103What can happen when binding proteins for vitamin A are overwhelmed?
Free vitamin A can damage cells, leading to toxicity.
104What forms of vitamin A are associated with toxicity?
Pre-formed vitamin A from animal sources, fortified foods, and supplements.
105What are some health issues related to excessive vitamin A intake?
Bone defects (osteoporosis) and birth defects (Cell death in the spinal cord)
106Why do women have to take a pregnancy test before starting acne medication?
Retin-A and Accutane are vit A relatives and pregnancy test is done to be sure that woman does not give a fetus excess vit A
107What is the effect of beta-carotene on vitamin A toxicity?
Beta-carotene, found in fruits and vegetables, is inefficiently converted to vitamin A, so it does not cause toxicity issues.
108What are the effects of overconsumption of beta-carotene from food and supplements?
Overconsumption from food may cause yellow skin (not harmful), while supplements may turn the antioxidant into a prooxidant, which can be harmful.
109Is vitamin D an essential nutrient?
No, vitamin D is not considered an essential nutrient because the body can synthesize it.
110How does the body synthesize vitamin D?
From sunlight and a precursor from cholesterol (7-DHC).
111What are the two hydroxylation reactions needed to activate vitamin D?
One in the liver (carbon 25) and one in the kidneys (carbon 1).
112What is the active form of vitamin D?
A hormone that regulates blood calcium levels.
113How does sunlight affect vitamin D synthesis?
Sunlight can degrade the vitamin D precursor with prolonged exposure, but normal sun exposure does not risk toxicity.
114How much sun exposure is generally sufficient for vitamin D synthesis?
5 to 10 minutes of summer sun 2-3 times a week, with more time needed in winter.
115What factors affect vitamin D synthesis from sunlight?
Skin color, latitude, season, and time of day.
116What role does parathyroid hormone play in vitamin D function?
It activates vitamin D.
117What does active vitamin D do in the body?
Regulates blood calcium levels by telling the intestines to absorb calcium, the kidneys to retain calcium, and the bones to release calcium.
118What is the role of calcitonin in calcium regulation?
Calcitonin has the opposite effect of vitamin D on intestines, kidneys, and bones, lowering blood calcium levels.
119What is the difference between overt signs of vitamin D deficiency and insufficiency?
Overt signs are rare, but insufficiency is quite common.
120What factors contribute to vitamin D insufficiency?
Dark skin, breastfeeding without supplementation, lack of sunlight, and not using fortified milk.
121What is rickets?
A condition in children where bones fail to calcify normally, causing them to bend.
122What is osteomalacia?
A condition in adults characterized by poor mineralization of bones, leading to soft, flexible, brittle, and deformed bones.
123How does osteomalacia differ from osteoporosis?
Osteomalacia involves poor mineralization and soft bones, while osteoporosis involves porous, spongy bones.
124What are the toxic effects of excessive vitamin D intake?
Raises blood calcium concentrations, forms stones in soft tissues, may harden blood vessels, and can cause death.
125Which vitamin is most likely to have toxic effects, especially from supplements?
Vitamin D.
126How many different tocopherol compounds are there for vitamin E?
Four—alpha, beta, gamma, and delta.
127Which tocopherol compound has the primary vitamin E activity in the body?
Alpha-tocopherol.
128What does the term "tocopherol" mean?
"To produce offspring."
129What is the main role of vitamin E as an antioxidant?
To stop the chain reaction of free radicals producing more free radicals and to protect cells and their membranes.
130How does vitamin E protect against heart disease?
By protecting LDLs and reducing inflammation.
131Is primary vitamin E deficiency common or rare?
Primary deficiency is rare.
132What causes secondary vitamin E deficiency?
Fat malabsorption from diseases such as cystic fibrosis.
133What are some effects of vitamin E deficiency?
Red blood cells breaking open (erythrocyte hemolysis), hemolytic anemia, thrombocytosis, and edema.
134What condition is associated with erythrocyte hemolysis and vitamin E deficiency?
Hemolytic anemia.
135How does cystic fibrosis contribute to vitamin E deficiency?
It causes fat malabsorption, which can lead to vitamin E deficiency.
136Is vitamin E toxicity common or rare?
Toxicity is rare.
137What is the upper limit (UL) for vitamin E intake compared to the recommended intake for adults?
The UL is 65 times greater than the recommended intake for adults.
138What may occur with extremely high doses of vitamin E?
It may interfere with vitamin K activity and increase the risk of hemorrhage.
139What is the primary role of vitamin K?
Acts as a cofactor for an enzyme used to activate blood clotting factors.
140Which blood clotting factors require vitamin K for activation?
Factors II, VII, IX, X, and thrombin.
141What role does vitamin K play in bone metabolism?
It is a cofactor for osteocalcin, which helps with bone protein storage and maintaining bone density.
142How common is primary vitamin K deficiency?
Primary deficiency is rare because bacteria in the GI tract produce about half of the daily amount needed.
143What causes secondary vitamin K deficiency?
Fat malabsorption (e.g., failure to make bile) and disruption of vitamin K’s synthesis and action by some drugs (e.g., antibiotics and anticoagulants).
144How do anticoagulants affect vitamin K?
They prevent vitamin K from performing its function and inhibit its resetting process. Warfarin specifically stops the resetting of vitamin K.
145What role does vitamin C play in collagen formation?
It acts as a cofactor in collagen formation, which is essential for the matrix of bone and tooth formation.
146What other reactions does vitamin C assist with?
Conversion of tryptophan to serotonin and tyrosine to norepinephrine.
147How does vitamin C function as an antioxidant?
It defends against free radicals and protects tissues from oxidative stress, aiding in disease prevention.
148What is the evidence regarding vitamin C's effectiveness in preventing and treating the common cold?
Research is conflicting and controversial.
149How does vitamin C affect histamine?
It deactivates histamine.
150What are notable signs of vitamin C deficiency?
Bleeding gums around teeth and spontaneous breaking of capillaries under the skin.
151What disease is associated with vitamin C deficiency?
Scurvy.
152What are common side effects of vitamin C supplementation?
Diarrhea and gastrointestinal distress.
153How can high doses of vitamin C interfere with medical regimens?
It can give inaccurate results in urine tests for diabetes.
154What medical conditions should avoid high doses of vitamin C?
Kidney disease, gout, and diseases affecting vitamin C breakdown.