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67 terms

Antioxidant

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Name the antioxidant nutrients
Alpha-carotene
Beta-carotene
Cryptoxanthin
Lycopene
Lutein
Zeaxathin
Antioxidant
a chemical that can stop the destructive chain reactions of free radicals, among the nutrients, vitamins c and e, betacarotene, and the mineral selenium are examples
Oxidation
The loss of electrons from a substance involved in a redox reaction.
Peroxidation
the process by which free radical oxygen attacks a double bond in a fat. causes rancidity
atom
(physics and chemistry) the smallest component of an element having the chemical properties of the element
Electron
an elementary particle with negative charge
Reduction
any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen)
Stable molecule
contain an even number of paired electrons
Free radical
an atom or group of atoms with at least one unpaired electron
Tocotrienol
biologically inactive form of vitamin E
tocopherol
a fat-soluble vitamin that is essential for normal reproduction
Provitamin
An inactive form of a vitamin that the body can convert to an active form. An example is beta-carotene.
Cofactors
Any nonprotein molecule or ion that is required for the proper functioning of an enzyme. Cofactors can be permanently bound to the active site or may bind loosely with the substrate during catalysis
What causes free radical formation?
X-ray photons interact with water in cells, ionization occurs which results in free radicals formation
How does a free radical cause cellular damage?
Steals an electron from a molecule destabilizing it and then causing a domino effect of damage to other cells. This makes them more susceptible to disease
What damage does a free radical cause?
Damage to cell membranes, LDLs, proteins in the cell, and genetic material.
What diseases are associated with free radical damage?
Cancer, eye damage, heart disease, aging
What are the 2 ways that antioxidants can function against free radicals?
Some vitamins can donate their electrons to free radicals to stabilize them. Some minerals act with complex enzyme systems to destroy free radicals.
vitamin E
a fat-soluble vitamin that is essential for normal reproduction
Is it Fat soluble or water soluble
Fat
Recommended intake of Vit E
15mg/day alpha tocopherol
UL for Vit E
1,000 mg
Food sources of Vit E
vegetable oils, nuts, seeds, wheat germ, soybeans
Toxicity symptom of Vit E
Augment (Increases) the effects of anti-clotting medication
What effects bioavailability of Vitamin E
oxygen, metals, light and heat
What deficiency symptoms can occur with Vitamin E?
Hemolytic anemia
Vitamin C
ascorbic acid
2 forms of Vitamin C
Ascorbic acid and dehydroascorbic acid.
Vit C: fat or water soluble
water soluble
vitamin C
-Antioxidant
-protects cells
-protects E (E protects A)
-used a preservative
-assists with help of stress
-immunity: enhances response, protect against infection
-collagen formation- scars, ligaments, and tendons, teeth, bones
-common cold: questionable, poss weak antihistamine effect, placebo effect
Recommended intake of vit C
90 mg/day for men
75 mg/day for women
Food sources of Vit C (look beyond citrus)
Many fruits and vegetables, including potatoes, citrus fruits, tomatoes, broccoli, strawberries, kiwi, cabbage, spinach
Toxicity symptoms with Vit C
nausea, abdominal cramps, diarrhea, nose bleeds, can lead to kidney stones
Deficiency disease of Vit C
scurvy: microcytic anemia, artherosclerotic plagues, petechia( pin point hemorrhages under the skin) bone fragility/pain
decrease wound healing, infections, bleeding gums, loose teeth, muscle degeneration/pain, rough skin, depression, hysteria
What effects bioavailability of Vitamin C
heat, light destroys it. cooking in water leaches Vit C into the water and out of the food
Beta Carotene is the provitamin of ?
Vitamin A
Functions of carotenoids generally are?
Enhance the immune system, protect skin from damage by UV light, protects eyes from damage
Functions of beta carotene specifically is?
Weak antioxidant, effective against oxidation in cell membranes and LDLs
Recommended intake of Beta carotene
900 mg per day for men, and 700 mg per day for women.
Food sources of beta carotene
dark green leafy veggies, deep orange fruits (apricots, cantaloupe) and veggies (squash, carrots, sweet potatoes, pumpkin)
Bioavailability of beta
Requires fat to be absorbed, Absorbs 20-40%, Affected by the amount you eat, Cooking enhances absorption, Fiber reduces absorption
Toxicity of beta carotene
harmless yellowing of skin
Bioavailability of beta
Requires fat to be absorbed, Absorbs 20-40%, Affected by the amount you eat, Cooking enhances absorption, Fiber reduces absorption
Toxicity of beta carotene
harmless yellowing of skin
Deficiency of beta
Signs of vitamin A deficiency include night blindness, fatigue, skin disorders, and a weakened immune system. Xerophthalmia results from severe vitamin A deficiency and is a leading cause of blindness in the underdeveloped parts of the world.
Vitamin A fat soluble or water
fat soluble
3 active forms of Vitamin A
1. retinol-alcohol form 2. retinoic acid-acid form 3. retinoids
Where is vitamin A stored?
Excess vitamin A is stored in the liver, adipose tissue, kidneys, and lungs
Functions of vitamin A
...
Recommended intake of A
Men- 900mcg of RAE/day, Women- 700mcg of RAE/day/day
Food sources of vitamin A
Retinoid-Fish, fish oils, fortified milk, and eggs.
Carotenoids -Red, orange, dark green, and yellow veggies.
Bioavailability of vitamin A
Requires fat to be absorbed, Approximately 75% of Vitamin A is absorbed
Bioavailability of vitamin A
highly stable food, imporoved absorption with cooking
Deficiency disease of Vit A?
hypovitaminosis A: night blindness, corneal drying(xerosis), triangular gray spots on eyes (Bitot's spots) cornea softening (keratomalacia) corneal degeneration and blindness (xeropthalmia) impaired immunity, hair follicles plugged with keratin forming white lumps (hyperkeratosis)
What is the role of Vitamin A in vision?
...
Selenium trace or major
trace mineral
Function of selenium
Defends against oxidation as a cofactor in the glutathione peroxidase enzyme system which destroys free radicals. Metabolism of thyroid hormone
What form is selenium in the body
Selenomethionine- storage form, Selenocysteine- active form
Recommended intake of selenium
Adults: 55micrograms/day
UL selenium
400 mcg/day
Food sources of selenium
meat, seafood, cereal, grains, dairy foods, fruits, vegetables, amount varies depending on soil content, brazil nuts noted to be high in selenium
Bioavailability of selenium
50-90% absorbed from small intestine
Vitamins A, C and E increase absorption
Blood levels of glutationine
Phytates decrease absorption
Toxicity of selenium
GI disorders, loss of hair, nails, skin lesions and nervous system disorders
Deficiency of selenium
Keshan disease: a heart disease
Kashin-Beck disease: deforming arthritis
Impaired immunity
What is the relationship between selenium and Vit E?
Necessary for glutathione peroxidases a family of antioxidant enzymes. Adequate amounts of these antioxidant enzymes reduce the need for Vitamin E. Thereby "sparing" it. Also regenerates Vitamin C after it has be oxidizedl
What is the relationship between Vitamin E and Vitamin C?
Helps to recycle oxidized vitamin E for reuse in the cells.
What is glutathione peroxidase and how does it protect against free radicals?
Part of the enzyme systems that destroy free radical damaged cells. Specifically glutathione peroxidases promote the breakdown of fatty acids that have undergone peroxidation and membrane damage.