Vitamins Flashcards
what are vitamins?
organic nutrients that are required in small quantities for a variety of biochemical functions and which generally cannot be synthesized in the body and must be supplied by the diet. 13 are universally recognized.
vitamins function in vivo as… (3 answers)
coenzymes or their precursor - components of the antioxidative defense system - factors involved in genetic regulation
what are the 13 vitamins?
A, B1, B2, B3, B6, B7, B8, B9, B12, C, D, E, K
what does vitamin restoration mean?
addition to reach the “original” concentration of nutrients
what does vitamin fortification mean?
addition of nutrients to make the item a good or superior source of that nutrient
what does vitamin enrichment mean?
addition of specific amounts of selected nutrients according to the standards of FDA
what does vitamin nutrification mean?
generic term for any addition of nutrients to foods
what is a fat-soluble vitamin?
one that can dissolve in lipid solutions, these are absorbed in the intestinal tract with the help of lipids
what is a water-soluble vitamin?
can dissolve in water solutions. these are readily excreted from the body
what is hypervitaminosis?
a condition of abnormally high storage levels of vitamins, which can lead to toxic symptoms.
which vitamins are primarily at risk in hypervitaminosis?
fat-soluble since these are stored by the body for longer period than the water-soluble vitamins
which vitamins are the least stable?
folate and ascorbic acid may be lost 100% in cooking. B1(thiamin) 80%, K, B2(riboflavin) and B3(niacin) 75%
when to tomatoes contain the most vitamin C?
just before maturation, then it decreases again
why do we need vitamin A, retinol?
it is needed by the retina (näthinna) as retinal combines with the protein opsin to form rhodopsin, a light-absorbing molecule
what is another function of vitamin A in the body?
an important hormone-like growth factor for epithelial and other cells
what role do carotenes play in vitamin A metabolism?
it is cleaved by an enzyme and converted to retinol in herbivores and omnivores. pure carnivores cannot and carotenes do not act as vitamin A in these animals
deficiency of retinol may cause
night blindness, xerophthalmia (total blindness), abnormal bone development, disorders of reproductive system
what are some sources of retinol?
cod liver oil, liver, chili, sweet potato, carrot, broccoli, butter, kale
what are the problems of hypervitaminosis A?
altered bone metabolism and altered metabolism of other fat-soluble vitamins
what causes hypervitaminosis A?
ingesting too much preformed vitamin A from foods like liver, supplements of prescription medications
why does provitamin carotenoids not cause hypervitaminosis A ?
conversion from carotenoids to the active form of vitamin A is regulated by the body to maintain an optimum level of the vitamin. carotenoids themselves cannot produce toxicity
what are possible symptoms of hypervitaminosis A?
blurred vision, decreased appetite, drowsiness, headache, skin conditions, hypercalcemia, liver damage, cracking at corners of mouth, spontaneous fractures
how is vitamin D3 synthesized?
by UV irradiation on precursors, spontaneous rearrangement occurs. in fungi and animals
why is vitamin D not synthesized in plants?
they do not have the necessary precursors
what are some sources of vitamin D?
dairy, fish, liver, egg
what is the physiological role of vitamin D?
enhancing calcium absorption, regulates mineral concentration of calcium and phosphorus, immune system, muscular function, cardiovascular function, respiratory systems, brain development
deficiency of vitamin D causes
rickets: bone softening, leading to deformity of long bones in children. bone thinning disorder, muscle weakness and bone fragility in adults, and osteoporosis (decreased bone mineralization)
hypervitaminosis D shows symptoms:
dehydration, vomiting, decreased appetite, irritability, constipation, fatigue, muscle weakness
excess of vitamin D causes
abnormally high blood concentrations of calcium, and may cause vitamin K depletion
vitamin E includes several types of compounds, which?
tocopherols and tocotrienols, determined by different short side chains
what is the physiological role of vitamin E?
protects cell membranes and tissues from damage by oxidation, aids in the formation of red blood cells and the use of vitamin K, promotes function of a healthy circulatory system
deficiency of vitamin E causes
mild anemia, reproductive disorders, fragile red blood cells, cataracts, neurological damage; muscle, liver, bone marrow and brain function abnormalities
what are some sources of vitamin E?
vegetable oils, nuts and seeds, sundried tomates
hypervitaminosis E shows as
blotchy skin, increased bleeding, increased blood fats, decreased production of thyroid hormones, decreased vitamin K activity, increased bleeding from aspirin or anti-coagulant medications
where is vitamin K found?
salad and kale greens, cheese, goose liver paté, natto
what is the physiological role of vitamin K?
play an essential role as cofactor for the enzyme gamma-glutamyl carboxylase. is also cofactor in the formation of coagulation factors. required for bone protein formation.
deficiency of vitamin K causes
reduced or enabled blood clotting, potentially bleeding, purple spots on skin caused by broken capillaries
hypervitaminosis K leads to
the true upper limit is less clear, but toxicity has not been reported. overdose could lead to liver damage.
which vitamins are fat-soluble?
A, D, E, K
which vitamins are water-soluble?
C and the B-vitamins
where can ascorbic acid (vit C) be found in plant sources?
fruits and vegetables.
can vitamin C be found in animal sources?
yes! most animals (excluding humans, monkeys, guinea pigs and fruit bats) make their own vitamin C. It is most present in the liver and least present in the muscle.
what is the physiological role of vitamin C?
promotes a healthy immune system, helps wounds heal, maintains connective tissue and aids in absorption of iron.
deficiency of vitamin C causes
scurvy, reduced vision, weakness, anemia
vitamin C toxicity shows as…
diarrhea, iron poisoning, vomiting, headache, skin rashes. however since vit C is water-soluble, dietary excesses will be excreted in the urine.
what roles do B-vitamins generally play in the body?
either cofactor (generally a coenzyme) for key metabolic processes or a precursor needed to make one.
vitamin B1 is also called
thiamine
vitamin B2 is called
riboflavin
vitamin B3 is called
niacin
vitamin B5 is called
panthothenic acid
vitamin B6 is called
pyridoxine
vitamin B7 is called
biotin
vitamin B9 is called
folate
vitamin B12 is called
various cobalamins
thiamine plays a central role in…
the release of energy from carbohydrates. is involved in RNA and DNA production, nerve function. its active form is a coenzyme called thiamine pyrophosphate (TPP) which takes part in the conversion of pyruvate to acetyl coenzyme A in metabolism
where do humans store thiamine?
25-30 mg in skeletal muscle, heart, brain, liver and kidneys
what are sources of thiamine?
thiamine biosynthesis occurs in bacteria, protozoans, plant and fungi. whole grain, legumes, some meat and fish
deficiency of thiamine causes
beri-beri (cells cannot use energy from carbohydrates),, nerve damage, brain disorders, fatigue, headache, gut issues, muscle weakness
what could be a cause for vitamin B1/thiamine deficiency?
overconsumption of alcohol or consuming a diet low in animal products.
toxicity of thiamine causes
allergic reactions including anaphylaxis at levels 100 times over DRI. side effects are generally few.
how could thiamine be degraded in food?
sulfites may cleave the molecule, faster in acidic pH. enzymes present in raw fish and shellfish or produced by bacteria may degrade thiamine. rumen bacteria can reduce sulfate to sulfite, so high dietary intakes of sulfate can have thiamine-antagonistic activities.
what does the name riboflavin come from?
from the ribose and flavin that constitute the molecule,
what are sources of riboflavin?
animal products, legumes, salad greens, whole grain
what is the physiological role of riboflavin?
metabolism of carbohydrates, fats and proteins, immune system, antioxidant properties, nervous system, skin, hair, nails
deficiency of riboflavin causes
anemia, fatigue, night blindness, swollen tongue
riboflavin toxicity…
there is no evidence for riboflavin toxicity produced by excessive intakes, hence no upper limit level
can niacin be made in the body?
the liver can synthesize niacin from the essential amino acid tryptophan. 60 mg tryptophan make one mg of niacin.
what are dietary sources of niacin?
meat, mushrooms, potato, whole grains, seeds
what is the physiological role of niacin?
in fat, carbohydrate and protein metabolism, nerves, skin, digestive system.
deficiency of niacin causes
Pellagra, commonly regerred to as 3 D:s: dermatitis (skin inflammation) - dementia - diarrhea (can lead to death
toxicity of niacin causes
headache, stomach/intestinal problems, acute vasodilation lower blood pressure, elevating blood sugar
what is panthothenic acid (provitamin B5)
a part of CoA, which we break off, absorb and make our own CoA
what are food sources of panthothenic acid?
mushrooms, goat cheese, fish, avocado, eggs, pork
deficiency of panthothenic acid causes
disorder of the functions of the heart, kidneys, stomach, intestine - metabolic disturbance - dermatitis - coordination of movements disorder - nervous system disorder
toxicity of panthothenic acid causes
does not seem to have any maximum intake. huge doses yield mild intestinal distress.
what is the physiological role of vitamin B6 (pyridoxine)?
important in maintaining healthy brain function, formation of red blood cells, breakdown of protein, synthesis of antibodies. it acts as a coenzyme.
deficiency of pyridoxine causes
weakness, sleeplessness, dermatitis, anemia, nerve damage, seizures, loss of appetite
what are sources of vitamin B6(pyridoxine)?
animal products are the best sources but also whole grain, legumes
what is the physiological role of biotin (B7)?
metabolism of fats and carbohydrates, liver and pancreas, protects from diabetes, healthy hair and nails, normal function of blood vessels and intestinal mucosa
deficiency of biotin causes
skin peeling, hair loss, white tongue, muscle pain, high cholesterol, anemia
where is biotin found?
liver, legumes, butter, seeds and nuts
physiological role of folate/folic acid (B9)
coenzyme, needed for normal cell division. especially in pregnancy and infancy which are times of rapid growth. production of red blood cells.
what are sources of folic acid?
legumes, salad greens, asparagus, broccoli
what is the difference between folic acid and folate?
folate is natural and has higher bioavailability than the synthetic folic acid.
deficiency of folic acid causes
anemia, decreased appetite, weakness, sleeplessness. spina bifida (spinal cord displaced) in pregnancy.
health risks from excess folate
since folate is water-soluble the risk of toxicity is low. large amounts of folic acid may “mask” some symptoms of vitamin B12 deficiency until it’s too late to do anything about it
what is the physiological role of vitamin B12?
metabolism, formation of red blood cells, maintenance of CNS
vitamin B12 deficiency causes
fatigue, depression, headaches, poor memory. extreme deficiency causes neurological damage and anemia.
what are sources of vitamin B12?
it is produced by bacteria in ruminant guts, some animals eat poop since colon bacteria produce b12. animal products, enriched products
what are some conditionally essential vitamin-like compounds?
choline(included in phospholipids, human synthesis is insufficient), betaine(breakdown product of choline), carnitine (a.a. derivative, synthesized in the body but some people benefit from addition, part of fatty acid transport), coenzyme Q10 (coenzyme in mitochondria, antioxidant, synthesized in body but dietary sources may be important in cases of reduced synthesis or increased use)
