Vitamins, Antioxidants, and Free Radical Scavengers Flashcards
1
Q
What are vitamins?
A
Vitamins are macronutrients required by the body to carry out a range of normal functions. However, these macronutrients are not produced in our bodies and must be derived from the food we eat
- Not produced by the body so need to get them from food
2
Q
Vitamins?
A
- Organic compounds essential for normal functioning growth and maintenance of the body
- Needed in small amounts (fat soluble especially)
- Not an energy source
- Individual units rather than long chains
3
Q
How does food preparation affect vitamin?
A
Factors that determine amounts
- Source (animal vs. plant)
- Sunlight
- Moisture
- Growing conditions
- Plant’s maturity at harvest
- Packaging and storage
By cooking food or preserving it, vitamins can be lost
4
Q
Mandatory Fortification of foods in Canada?
A
- Fortified vitamin D in milk
- Folate and niacin must be added to flour
- Potential problems – junk foods and deception
5
Q
What is a consequence of vitamin D deficiency?
A
Not taking in as much calcium
6
Q
Why are some people vitamin deficient?
A
- Some people are deficient in enzymes to uptake vitamins
- Some medication prevents some vitamin uptake
- At different times in life, need more/less vitamins
7
Q
What are provitamins?
A
- Inactive forms of vitamin
- Body must change them to active form
Example: Beta-carotene
Need enzymes to break it down to be able to absorb it as vitamin A
A provitamin is a substance that may be converted within the body to a vitamin
8
Q
What are the types of vitamins? (2)
A
- Water soluble
- Fat-soluble
9
Q
Water soluble vitamins?
A
B1: thiamine
B2: riboflavin
B3: Niacin
B5: pantothenic acid
B6: pyridoxine
B7: Biotin
B9: Folic acid
B12: Cobalamin
C: ascorbic acid
10
Q
Fat-soluble vitamins?
A
A: Retinol-al-oic acid
D: Cholecalciferol
E: Tocopherol
K: Phylloquinone
11
Q
Differences in Vitamin Digestion?
A
Micelle: aggregate of surfactant amphipathic lipid molecule dispersed a liquid forming a colloidal suspension
Important in transport of vitamins into the intestinal epithelial cells
Chylomicrons: important in the movement of vitamins from gut epithelial cells into the lymphatics
12
Q
What system takes up vitamins first?
A
The lymphatic system takes up vitamins first, it is involved in immune function
13
Q
Fat soluble molecules features?
A
- Vitamins A, D, E, and K have lipid solvent solubility, diverse nonenzymatic functions, sequestration in lipid vacuoles and adipose, and greater risk for toxicity
14
Q
How are fat soluble molecules absorbed?
A
- Like dietary triglycerides, fat-soluble vitamins are solubilized in the duodenal lumen in the presence of bile and pancreatic enzymes
- Fat-soluble vitamins are maintained within the lipophilic core of mixed micelles
- Next, pancreatic esterase’s, in the presence of bile salts, catalyze the release of fat-soluble vitamins from esters
- Stays in the body longer than water soluble vitamins, fat-soluble can accumulate
15
Q
Absorption of Fat soluble vitamins?
A
Fat soluble vitamins
Together with fatty acids derived from triglycerides, fat-soluble vitamins are released from micelles at the enterocyte brush border membrane
At high doses, vitamins A and E can be absorbed directly from water-miscible emulsions. The next steps involve incorporation into the chylomicrons for secretion into lymphatics and ultimate uptake by the liver
Intestinal, biliary, and pancreatic diseases that cause decreased dietary lipid absorption may cause a decrease in the absorption of fat-soluble vitamins
16
Q
Vitamin A also known as?
A
The retinoids
17
Q
What are the active forms of Retinoids?
A
Retinol
Retinal
Retinoic Acid
o Precursors (carotenoids)
Adapalene is a retinoid
18
Q
Vitamin A is important in what? (6)
A
- Vision: night and day
a. Becomes part of retina
b. Keeps eye surface healthy
c. Allows night and colour vision - Immune function
a. Produce immune cells to fight microorganisms - Cell production and differentiation
a. Regulates production of enzymes, blood carrier proteins, and structural proteins (like those in skin) - Skin
a. Needed to replace epithelial cells of you skin - Reproduction
a. Keep reproductive tracts healthy
b. Women: maintain fertility, Men: sperm production
c. Embryo development - Bones
a. Helps produce bone cells
b. Required for bone remodeling a increase in osteoclasts
19
Q
Vitamin A and vision?
A
Vitamins A is a precursor of rhodopsin, the pigment found in rods within the retina, helps us see at night.
Without vitamin A “night blindness” occurs
Rods are not properly formed if Vitamin A deficient
20
Q
Rod vs Cones?
A
Rods outnumber cones 20:1
Rods: night vision
Cones: day vision
Vitamin A is a required precursor for the formation of rhodopsin, the photopigment in rods
21
Q
Sources of Vitamin A?
A
Will get enough if you have a balanced diet
Exceptional source: beef liver carrots, sweet potatoes
High sources: spinach, mango, broccoli
Good sources: dried plums, milk
22
Q
Vitamin A deficiency can lead to?
A
- The issue in the eye
o Xerophthalmia (inability to see - The skin and other epithelial cells
o Keratin issues - Immune function
o Vulnerable to infection - Other effects
o Growth retardation, bone deformations, defective teeth, and kidney stones
23
Q
Vitamin A toxicity symptoms?
A
- Fatigue, vomiting, abdominal pain, bone and joint pain, loss of appetite, skin disorders, headaches, blurred or double vision, liver damage
1. Teratogen (birth defects, if have too much when pregnant
a. Agent that causes birth defects: clef palate, heart abnormalities
2. Discoloration of skin
3. Acne treatment: Retin A and Accutane
(vitamin A is used in a lot of beauty product which can be bad during pregnancy)
Vitamin A has been linked to an increased risk for hip fracture in postmenopausal women, lung cancer, cardiovascular mortality and total mortality
24
Q
Vitamin D forms?
A
Forms:
- Activated in the liver and kidney
- 25-hydroxyvitamin D [25(OH)D]
25
Vitamin D functions?
- Essential for bone health
- Helps regulate insulin formation and secretion
- Calcium absorption
26
Vitamin D sources?
- Exposure to sunlight
- Fortified foods, milk, cereal
- Oily fish, egg yolk, cod liver oil
- supplements
27
Why is vitamin D needed in the body?
1. vitamin D enters the body from the diet or the synthesis in the sky
2. vitamin D must be chemically modified first by the liver and then by the kidneys to function
3. active vitamin D increase the absorption of calcium and phosphorus in the intestines
4. active vitamin D also increases bone breakdown which releases calcium and phosphorus into the blood, at the kidneys, calcium retention is stimulated reducing the amount lost in the urine
5. normal levels of blood calcium and phosphorus support mineralization of the bones
28
What is Vitamin D soluble in?
Chylomicrons
29
Vitamin D signaling?
Vit D binds VDR in the cytoplasm, moves into the cell nucleus
In nucleus binds RXR (retinoid X receptor)
This binds to the transcription factor (VDR response element)
This regulates gene coding
To regulate: proliferation, differentiation, apoptosis, oxidative stress, membrane transplant, Inflammation, tissue mineralization, adhesion
30
Vitamin D deficiency?
Deficiency
- rickets in children (impaired calcium absorption, bones don’t form)
- Osteomalacia and osteoporosis in adults
31
Vitamin D toxicity?
Toxicity:
- Hypercalcemia (stones, groans, thrones, psychiatric overtones), calcium stones
- Usually, minimal
Newborns are usually given Vitamin D supplements (especially in winter)
32
Does Vitamin D have chemo preventative properties?
Vitamin D has no chemoprevention effects (doesn’t prevent cancer)
33
Vitamin E forms?
- Family of 8 similar compounds
- Only alpha tocopherol considered for human vitamin E requirement
- Stored mainly in body fat
34
Vitamin E functions?
- Antioxidant
o Protects cell membranes from free radicals
o May lower risk of some chronic diseases
It has many effects on tissue systems
35
Dietary recommendations of Vitamin E?
Dietary recommendations
- Related to intake of polyunsaturated fatty acids
- RDA
o 15mg/day alpha tocopherol
o 19mg/day for breastfeeding
36
Vitamin E sources?
- Nuts, seeds, vegetable oil, whole grain, fruit, vegetables, animal products
37
Vitamin E Deficiency?
Deficiency:
- Occurs with fat malabsorption or rare genetic disorders
38
Vitamin E toxicity?
Toxicity:
- Nontoxic and adverse effects have not been found
- Can interfere with blood clotting
- Lung injury when inhaled, banned from e-cigarettes
39
Vitamin K forms?
K1 and K2
40
Vitamin K functions?
- Blood clotting
- Bone health
41
Dietary recommendations Vitamin K?
- Men: 120mg/day
- Women: 90mg/day
42
Vitamin K and thrombosis?
It is necessary for the synthesis of thrombin, thus it is necessary in coagulation of blood
If you have a deficiency in vitamin K, at risk of excess bleeding
Vitamin K promotes the synthesis of coagulation factors - thrombin
Warfarin (anticoagulant) interferes with vitamin K synthesis
43
Vitamin K sources?
- Green vegetables, plant oils, intestinal bacteria
44
Vitamin K deficiency?
Deficiency:
- Rare in healthy people
- Newborn babies at risk
45
Vitamin K toxicity?
Toxicity:
- Rare
- Can interfere with anticoagulant medications
46
Water soluble vitamins?
- 8 B vitamins
o Act primarily as coenzymes in energy metabolism
- Vitamin C
o Antioxidant
o Can stabilize vitamin E
- They are directly absorbed into the bloodstream
47
What is a coenzyme?
A coenzyme is an organic non-protein molecule that is required by an enzyme to perform its catalytic activity
48
What are oxidants?
Oxidants are reactive molecules that are produced both inside the body and in the environment
They can react with other cellular molecules in your body such as protein, DNA, and lipids
When it does this, it damages molecules and its what causes disease and inflammation
49
What are antioxidants?
Compounds that inhibit oxidation, a chemical reaction that can produce free radicals
50
Vitamin B1 also known as?
Thiamin
51
Are B vitamins coenzymes?
yes
52
B1 functions
- Coenzyme in energy metabolism
- Part of the coenzyme thiamin pyrophosphate (TPP)
o Helps breakdown glucose to energy
o Make RNA and DNA
o Helps power protein
o Helps synthesize and regulate neurotransmitters
53
B1/Thiamin dietary recommendations?
- Men: 1.2mg/d
- Women:1.1mg/d
- Pregnancy: 1.4mg/d
- Breastfeeding: 1.5mg/d
54
B1 food sources?
- Pork, legumes, nuts, fish, seafood, enriched grain products
- Cooking reduces content
55
Thiamin/B1 deficiency?
- Beriberi: overall profound musce weaknes and nerve destruction
- Milder symptoms: headache, irritability, depression and loss of appetite
56
Thiamin toxicity?
none reported
57
Vitamin B2 also known as?
Riboflavin
58
B2/Riboflavin functions?
- Coenzyme in energy metabolism
- Supports antioxidants
59
B2 food sources?
- Milk and dairy products
- Enriched grains, eggs
60
Why is milk packaged in opaque containers?
- Light breaks down riboflavin easily, so foods high in riboflavin are stored in opaque containers
61
Riboflavin deficiency?
Deficiency:
- Ariboflavinosis
- Occurs most often in chronic alcoholism
62
B2/Riboflavin toxicity?
Toxicity:
- No reported cases
63
Ariboflavinosis/riboflavin deficiency symptoms?
Skin disorders, hyperemia (excess blood), edema of the mouth and throat, angular stomatitis (lesions at the corners of the mouth), cheilosis (swollen cracked lips), hair loss, reproductive problems, sore throat, itchy and red
64
Vitamin B3 also known as?
Niacin
65
Niacin functions?
- Coenzyme in energy metabolism
- Supports fatty acid synthesis
66
B3/Niacin food sources?
- Can be made from amino acid tryptophan
- Whole and enriched grains
- Meat, poultry, fish, nuts, and peanuts
67
Niacin deficiency?
Deficiency
- Pellagra
o Four Ds: dermatitis, diarrhea, dementia, and death
o Can worsen if also deficient in B1, B6 and iron
68
Niacin/B3 toxicity and medical uses?
Toxicity and medicinal uses
- High doses used to treat high blood cholesterol
- Side effects: skin flushing, liver damage
69
Vitamin B6 also known as?
Pyridoxine
70
Vitamin B6 functions?
Functions
- PLP, coenzyme in protein and amino acid metabolism, gluconeogenesis (aa to glucose)
- Produce non-essential amino acids
- Produce neurotransmitters and hemoglobin
- Helps to lower blood levels of homocysteine
71
Vitamin B6 food sources?
- Meat, fish, poultry, potatoes, fortified meat substitutes, bananas, sunflower seeds
72
Vitamin B6 deficiency?
Deficiency
- Microcytic hypochromic anemia
- Heart disease (high homocysteine)
- Damage nervous system – depression, headaches, confusion, convulsion
73
Vitamin B6 toxicity?
Toxicity and medicinal uses:
- Can cause subtle neurological damage
- Other symptoms: upset stomach, headaches, sleepiness, tingling, prickling, burning sensations
74
Vitamin B9 also known as?
Folate
75
Folate functions?
- Coenzyme in DNA synthesis and cell division
- Coenzyme in amino acid metabolism
- Needed for normal red blood cell maturation
- Works with B6 and B12 to help control homocysteine
76
Folate/B9 food sources?
Food sources
- Fortified cereals, enriched grains
- Green leafy vegetables (spinach), orange juice, sunflower seeds, and legumes
77
Folate deficiency?
Deficiency
Anemia and diarrhea
- Megaloblastic anemia
Birth defects
- Spina Bifida (externalized spinal nerves)
78
Folate toxicity?
- Can mask vitamin B12 deficiency with folate supplements
- Hypersensitive people may suffer hives or respiratory distress
79
Vitamin B12 also known as?
Cobalamin, cobalt containing compounds
80
Vitamin B12 functions?
- Needed for normal folate function
o DNA and red blood cell synthesis
o Metabolize homocysteine
- Maintains myelin sheath around nerves
81
Vitamin B12 food sources?
- Only animal foods: meats, liver, milk, eggs
- Some fortified foods
82
Vitamin B12 absorption?
Requires intrinsic factors
83
Vitamin B12 deficiency?
- Can lead to pernicious anemia, resulting in nerve damage
- Red blood cells can look enlarged (megaloblastic anemia)
84
Vitamin B5 also known as?
Pantothenic acid
85
Vitamin B5 functions?
component of coenzyme A
86
Vitamin B5 food sources?
- Widespread in foods
- Reduced by freezing, canning, and refining
87
B5/Pantothenic acid deficiency and toxicity?
Deficiency and toxicity is rare
88
Vitamin B7 also known as?
Biotin
89
Biotin functions?
- Coenzyme
- Amino acid metabolism (to glucose)
- Fatty acid synthesis
- Release of energy from fatty acids
- DNA synthesis
90
Biotin/B7 food sources?
- Cauliflower, liver, peanuts, cheese
- Protein avidin (raw egg whites) binds biotin and prevents absorption
91
Biotin/B7 deficiency and toxicity?
Deficiency and toxicity are rare
92
Vitamin C functions?
- Antioxidants
- Needed for collagen synthesis
- Enhances the absorption of iron from plant foods
- Makes other essential compounds (ex, steroid hormones, bile salts, thyroid hormones, parts of DNA)
93
Vitamin C food sources?
- Fruits: citrus, strawberries, kiwi, fortified juice
- Vegetables: broccoli, tomatoes, potatoes, cabbage, leafy greens, peppers
94
Vitamin C deficiency?
Scurvy
95
Vitamin C toxicity?
- May cause GI tract distress In high doses
