Vitamins Flashcards
A deficiency disease caused by the absence of vitamin C in the diet:
scurvy
Ascorbic acid –literally means:
without-scurvy acid
fat-soluble vitamins:
A, D, E, K
What is a vitamin?
A complex organic compound,
Vitamins, are not a source of
energy
vitamin precursors that do not function in the body until converted to active forms:
Provitamins
precursor to vitamin A:
Beta-carotene
precursor to niacin:
Tryptophan (amino acid)
vitamins are found in food that are usable my the body –without chemical transformation:
Preformed
Most vitamin absorption occurs in:
small intestine
water-soluble vitamins:
B and C
preformed vitamin A:
Retinol
the most active
form of the vitamin in the body;
retinol
Retinol and the other forms of vitamin A are only in:
animal foods
yellow-orange pigments:
carotenoids.
One such carotenoid is:
beta-carotene.
The body can use beta-carotene to make:
retinol
Vitamin A is crucial for production and maintenance of:
epithelial cells
Epithelial cells secrete:
mucus
xerophthalmia:
–permanent blindness
Keratinization:
hard, scaly/bumpy skin
Half a million children go blind each year because of:
vitamin A deficiency.
Green, leafy vegetables, (eg spinach and kale) have high concentrations of:
lutein and zeaxanthin.
Tomato juice and other tomato products contain considerable amounts of:
lycopene.
Although lutein, zeaxanthin and lycopene are carotenoids, the body does not:
convert them to vitamin A
Leading cause of blindness in elderly:
macular degeneration
Vitamin A is stored in the:
liver
Excess vitamin A is a:
teratogen
Adequate Vitamine D ensures:
strong bones
Vitamin D works with ______ to signal bones to release calcium:
parathyroid hormone (PTH)
PTH stimulates the kidneys to increase:
vitamin D production
PTH stimulates the kidneys to decrease:
the elimination of calcium in urine
active form of vitamin D:
Calcitriol
a major concern in developing countries:
rickets
breast milk contains insufficient amounts of vitamin D to prevent:
rickets
The adult form of rickets:
osteomalacia.
Excess vitamin D can cause the small intestine to:
absorbs too much calcium from foods.
how many forms of vitamin E?
8
alpha-tocopherol:
most active form of vitamin E
Vitamin E easily destroyed by:
cooking
major fat-soluble antioxidant
found in cells:
Vitamin E
– It donates an electron to free radicals:
Vitamin E
this vitamin protects polyunsaturated fatty acids in cell membranes from being damaged by radicals:
Vitamin E
substance that removes electrons from atoms or molecules:
oxidant (oxidizing agent)
An oxidation reaction can form a :
free radical
Vitamin E is also added to food to prevent:
oxidation
Vitamin E protects LDLs from being oxidized thus lowering risk of:
CVD
Vitamin K is important in:
Coagulation (Koagulation)
Important for the synthesis of blood-clotting factors in the blood:
Vitamin K
Without it, you could bleed to death from a minor cut.
Vitamin K
About 10% of our vitamin K is synthesised by:
the bacteria living in our large intestine.
infants have a sterile intestine, therefore they could:
Bleed to death
Infants are given:
a single dose of Vitamin K at birth
In the stomach, vitamins are released from:
protein complexes in food.
The vitamins are absorbed by the small intestine
and delivered to the liver via the:
portal vein
Liver keeps/stores:
B12
Excess water-soluble vitamins are eliminated through the:
kidneys in the urine
to understand the water soluble B-vitamins we need to understand:
coenzymes
the chemical reactions that involve the metabolism of carbohydrates, fats, and amino acids require:
B-vitamins.
B-vitamins work as
co-enzymes
Most water soluble vitamins are sensitive to:
heat
Most water soluble vitamins have numerous:
functions
Thiamin (B1) Major Functions in the Body:
– A coenzyme needed for macronutrient metabolism:
The thiamin-deficiency disease is called:
BeriBeri
Thiamin deficiency can also occur from:
alcoholism
Wernicke-Korsakoff:
alcohol interferes with thiamin absorption
Riboflavin (B2) • Major Functions in the Body:
– A coenzyme needed for macronutrient metabolism:
Exposure to light causes Riboflavin to:
break
down rapidly.
Riboflavin-rich foods, (e.g. milk) should not be packaged or stored in:
clear glass containers
30 minutes of UV light will destroy:
30% of riboflavin
What happens if riboflavin is missing from the diet?
– Fatigued easily. – Inflamed tongue, sores on the edges of the lips – But deficiency is very rare.
Niacin (B3) Major Functions in the Body:
participate in at least 200 reactions, including those involved in the release of energy from macronutrients!
We can produce some small amounts of niacin using:
The amino acid is tryptophan
What happens if niacin is missing from the diet?
– Pellagra disease
– Pellagra disease:
- Dementia
- Dermatitis
- Diarrhea
- Death
prison inmates fed a low protein diet developed:
Pellagra
Is niacin found in corn?
YES
The niacin content in corn is high, but is tightly bound to:
a protein that resists digestion.
people who eat corn as their staple food are prone to develop:
pellagra.
Vitamin B-6 is essential for:
amino acid metabolism
Without vitamin B-6, all amino acids become :
essential.
what is important for conversion of the amino acid tryptophan to niacin?
Vitamin B6
What is Required for synthesis of the heme in hemoglobin?
Vitamin B6
What is required for the Conversion of toxic homocysteine, to cysteine?
Vitamin B6
Without heme, hemoglobin cannot carry:
02
If vitamin B-6 is unavailable for heme synthesis, what develops?
anemia
megadoses of vitamin B-6 are:
toxic
In the body, cells convert all forms of folate to :
folate- coenzymes .
folate-containing coenzymes are needed to:
synthesize DNA
when to we have rampant DNA synthesis?
– During embryonic development.
The two neural tube defects are:
Spina bifida
Anencephaly
ALL wheat flour is fortified with:
folic acid
abnormal RBCs called:
megaloblasts
characterized by large, immature RBCs.:
Megaloblastic anemia
Vitamin B-12 maintain:
the myelin sheaths that insulate parts of certain nerve cells.
The natural vitamin B-12 in food is bound to:
proteins that prevent its absorption.
Hydrochloric acid and pepsin in the stomach release:
B-12 from the protein
Where is Vitamin B12 absorbed?
in the ileum
A healthy liver has enough vitamin B-12 reserves to last:
up to 5 years.
We rely almost entirely on animal foods to supply:
B-12
B-12 deficiency:
• Pernicious Anemia
Functions of Vitamin C
Collagen Synthesis
fibrousproteinthatgivesstrengthtoconnectivetissue
Collagen
the water-soluble antioxidant
Vitamin C
Vitamin C also may donate electrons to another antioxidant—
vitamin E
