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.