116 Questions
What is the defining characteristic of a radical species?
Contain one or more orbital electrons with unpaired spin states
What type of compound promotes oxidation?
Pro-oxidant
What is the primary action of radical species?
Seek and 'steal' electrons from other molecules
What is the defining characteristic of a radical species?
It contains one or more orbital electrons with unpaired spin states
What is the primary action of an oxidant?
Oxidizes other compounds
What is the role of an antioxidant in oxidation reactions?
Inhibits/reverses oxidation
What is the primary effect of radical species on cell proteins?
Causing damage to cell proteins
Which condition is NOT associated with the potential roles of radical species mentioned in the text?
Common cold
What is the impact of radical species on DNA?
Causing DNA mutations
What is the primary function of antioxidants in the body?
Prevent oxidation by donating electrons to stabilize radical species
Which of the following vitamins meets the definition of dietary antioxidants?
Vitamin C
Why are carotenoids included in the discussion of antioxidants despite not meeting the definition of dietary antioxidants?
Because they influence oxidative processes
Which of the following foods is NOT listed as a source of vitamin C in the text?
Apples
What is the oxidized form of ascorbic acid referred to in the text?
Dehydroascorbic acid
Why do smokers require more vitamin C according to the text?
Higher oxidative stress and metabolic turnover of vitamin C
What is the primary function of vitamin C as an enzyme cofactor?
Regulating reactions requiring reduced metal ions and protein synthesis
What is the impact of high concentration vitamin C intake on absorption?
Passive transport with less than 50% absorption
What is the effect of time release dose compared to single dose on vitamin C absorption?
Higher net absorption
What is the role of vitamin C in relation to radical species and antioxidants?
Scavenging radical species and regenerating other antioxidants
What is the source of released vitamin C in reaction to stress?
Adrenal glands
What is the primary role of vitamin C as an enzyme cofactor?
Assisting in collagen and connective tissue synthesis
What is the impact of high concentration vitamin C intake on absorption?
Passive transport absorption decreases
What is the key function of vitamin C's reducing power?
Acting as an effective antioxidant for scavenging radical species
What is the impact of time release dose compared to a single dose on vitamin C absorption?
Higher net absorption with time release dose
What is the role of released vitamin C in reaction to stress?
Exact role unclear, may relate to antioxidant function
At what pool size do scurvy symptoms occur in the body?
300 mg
What is the maximum body pool size of vitamin C in non-smokers per kg of body weight?
22 mg/kg
What happens to the excess of water-soluble compounds like vitamin C?
It is excreted via urine
What is the fate of large intake of water-soluble compounds like vitamin C in the body?
They are degraded in the intestine
What is the similarity between the bioavailability of vitamin C from food and pharmaceutical forms?
It is the same
What is a symptom of scurvy caused by vitamin C deficiency?
Inflamed, bleeding gums
In which countries is scurvy rare, unless there is low fruit and vegetable consumption?
Developed countries
Which species can synthesize vitamin C, unlike humans?
Most species
What is the Recommended Dietary Allowance (RDA) of vitamin C for women 19 years and older?
75 mg
What is the potential consequence of suddenly stopping a high dose of vitamin C intake?
Development of scurvy
What is the Tolerable Upper Intake Level (UL) for vitamin C in adults aged 19 and older?
2000 mg/day
Which form of vitamin E is mostly found in humans?
Alpha-tocophorol
What is the primary concern regarding vitamin E's function in some in vivo conditions?
Pro-oxidative function
What is the potential impact of vitamin E in protecting LDL from oxidation?
Decrease oxidative damage to LDL
What is the primary route of vitamin E excretion?
Through feces
What is the primary symptom of vitamin E deficiency?
Peripheral neuropathy
What is the primary source of vitamin E in food?
Vegetable oils & spreads
What is the primary concern regarding vitamin E toxicity?
Hemorrhagic stroke at high doses
What is the Recommended Dietary Allowance (RDA) of vitamin E for men aged 19-50 years?
15 mg/day alpha-tocopherol
How is vitamin E bioavailability affected by pharmaceutical forms?
Reduced due to lack of fats required for chylomicron formation
What is the primary fate of vitamin E in the body if there is low intestinal absorption?
Excreted through feces
What is the Tolerable Upper Intake Level (UL) for vitamin E in adults aged 19 and older?
1000 mg/day of any form of supplementary alpha-tocopherol
What is the biologically active form of selenium found in animal tissues?
Selenocysteine
Which food source is NOT listed as a good source of selenium in the text?
Leafy greens
How does food content of selenium vary depending on its source?
Depends on the soil content where the plant or animal was raised
What is the UL (Tolerable Upper Intake Level) of selenium for both males and females?
400 mcg/day
Which symptom is linked to selenium deficiency?
Muscular discomfort and weakness
What is the AI (Adequate Intake) of selenium for infants?
15 mcg/day
What is the primary route of selenium excretion from the body?
Urine
What is the Recommended Dietary Allowance (RDA) of selenium for men aged 19-50 years?
55 mcg/day
What is the primary function of Vitamin A in relation to men's health?
Supports sperm production
How is preformed Vitamin A absorbed in the small intestine?
It is hydrolyzed to retinol
What is the efficiency of absorption for preformed Vitamin A?
70-90%
What is the retinol activity equivalency (RAE) ratio for beta-carotene from food?
12:1
How can one calculate the amount of retinol that can be produced from dietary beta-carotene?
Divide mcg dietary beta-carotene by 12
Where is retinol stored in the body?
Liver
Which of the following foods is a good source of preformed Vitamin A?
Liver
What is the assumed conversion site of carotenoids to retinol in the body?
Intestines
Which factor is known to reduce the absorption of Vitamin A?
Intestinal infections
What is required for protein synthesis and is essential for Vitamin A absorption?
Zinc
Which substance competes with retinol for enzyme pathways in the body?
Ethanol
What are the symptoms of vitamin A toxicity?
Nausea, vomiting, headache, vertigo
Why is vitamin A toxicity from food unlikely in developed countries?
The body regulates the absorption of vitamin A from food
How does excess vitamin A from supplements cause cell damage?
It saturates protein carriers leading to free vitamin A which causes cell damage
What are the symptoms of Vitamin A toxicity?
Nausea, vomiting, headache, and blurred vision
What is the Recommended Dietary Allowance (RDA) of Vitamin A for men?
900 μg/day
What is the average Vitamin A intake for women aged 18 to 74 years?
1169 RAE (mcg)/day
What is the primary form of vitamin K found in fish oils and meats?
Menaquinone
Which food source contributes significant amounts of vitamin K?
Spinach
What is the primary function of vitamin K?
Blood clotting
Where is Phylloquinone absorbed in the body?
Jejunum & ileum
What is the AI for women for vitamin K?
90 mcg/day
What is the primary cause of secondary vitamin K deficiency symptoms?
Impaired fat absorption
What inhibits vitamin K absorption?
Antibiotics
Why are newborns given a vitamin K injection at birth?
To last until gut microflora are developed
Where does vitamin K toxicity primarily occur?
From excessive supplementation
What is the primary symptom of vitamin K deficiency?
Bruising and hemorrhage
What is the Adequate Intake (AI) of vitamin K for women?
90 mcg/day
What is the primary cause of secondary vitamin K deficiency symptoms?
Impaired fat absorption
What is the primary symptom of vitamin K deficiency?
Bruising and hemorrhage
What is the source of observed vitamin K toxicity in infants?
Excessive supplementation
What is the observed association of low vitamin K with chronic disease?
Osteoporosis
Why are newborns given a vitamin K injection at birth?
To prevent blood clotting inhibition
What is the approximate absorption rate of non-heme iron on average?
10%
Which type of iron is only found in flesh foods such as meat, poultry, and fish?
Heme iron
What is the primary factor that increases the absorption of non-heme iron?
Consumption of iron chelates like ascorbic acid
Where is the majority of body iron found?
In hemoglobin
What is the approximate absorption rate of heme iron on average?
10%
Which food source contains the most iron per gram of content?
Legumes
What is the primary form of iron in the cytochromes of oxidative phosphorylation?
Heme iron
Which factor influences the iron content in food?
Food processing methods
What is the primary plasma protein carrier for iron?
Transferrin
What is the most common cause of anemia?
Iron deficiency
What is the primary form of iron absorption inhibited by calcium and phosphorus?
Heme iron
What is the primary symptom of iron deficiency?
Blue sclera
What is the primary route of iron loss from the body?
Feces
What is the primary factor contributing to increased non-heme iron absorption?
Ascorbic acid
What is the primary contributor to iron stores in the body?
Dietary intake
What is the primary cause of increased iron absorption in individuals with low iron stores?
Enhanced absorption efficiency
What is the primary symptom of iron toxicity in children?
Lethargy
What is the Recommended Dietary Allowance (RDA) of iron for premenopausal women?
18 mg/day
What is the primary route of iron loss from the body?
Menstruation
What is the primary form of iron absorption inhibited by calcium and phosphorus?
Non-heme iron
What is the primary contributor to iron stores in the body?
Iron recycling from red blood cells
What is the primary symptom of iron deficiency?
Impaired intellectual performance
What is the Recommended Dietary Allowance (RDA) of iron for premenopausal women?
18 mg/day
What is the primary effect of radical species on cell proteins?
Promotion of oxidation
What is the primary form of iron in the cytochromes of oxidative phosphorylation?
Heme iron
What is the primary function of antioxidants in the body?
Preventing oxidation reactions
What is the primary form of vitamin E found in humans?
Tocopherols
What is the primary symptom of iron toxicity in children?
Organ damage
Test your knowledge on oxidants, pro-oxidants, antioxidants, and free radicals with this quiz. Learn about the properties and roles of these compounds in oxidation reactions.
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