Vitamins Flashcards
what are vitamins?
Vitamins are micronutrients (organic compounds) required by the body to carry out a range of normal functions
what are factors that determine the amount of vitamin that are readily available?
– Source (animal vs. plant)
– Sunlight
– Moisture
– Growing conditions
– Plant’s maturity at harvest
– Packaging and storage
what are reasons why we wouldn’t get enough vitamins?
- dietary interactions
- drug interactions
- physiological state
- disease
- genetic
- food processing
what is a provitamin?
a substance that may be converted within the body to a vitamin (is the inactive form)
what are the water-soluble and the fat-soluble vitamins?
- water: B1, B2, B3, B5, B6, B7, B9, B1, C
- fat: A, D, E, K
differences in absorption of water-soluble and fat-soluble vitamins.
fat:
- are solubilized by bile salts (make micelles)
- released at enterocyte brush border membrane
- incorporated into chylomicrons
- secretion into lymphatics and ultimate uptake by the liver (can accumulate in body)
water:
- can go through enterocytes
- go to blood vessels
- doesn’t stay long since it secreted in urine
what are the active and precursors of vitamin A?
- active: retinoids
- pre: carotenoids
vitamin A is important for:
- Vision: night and day
* Becomes part of the retina
* Keeps eye surface healthy
* Allows night and color vision - Immune function
* Produce immune cells to fight microorganisms - Cell Production and differention
* Regulates production of enzymes, blood carrier proteins,
And structural
Proteins (like those in the skin) - Skin
* Needed to replace epithelial cells of your skin - Reproduction
* Keep reproductive tracts healthy
* Women:maintain fertility; Men:Sperm production
* Embryo development - Bones
* Helps produce bone cells
* Required For bone remodeling a increase In osteoclasts
how does vitamin A affect vision?
- is a precursor of rhodopsin, the photopigment
found in rods within the retina of our eye that helps us to see at night. - Without vitamin A, “night blindness” occurs
what are sources of vitamin A?
- fruits and vegetables (carrot and sweet potato very high)
- liver
- oat/bran
- milk
what are the effects of vitamin A deficiency?
- eyes: Xerophthalmia (blindness)
- skin: hyperkeratosis
- immune: vulnerable to infection
- other: Growth retardation, bone deformations, defective teeth, and kidney stones
what are the effects of vitamin A toxicity?
- symptoms: Fatigue, vomiting, abdominal pain, bone and joint pain, loss of appetite, Skin disorders, headache, blurred or double vision, and liver damage
- is a teratogen
- causes skin discoloration
- acne treatment
how is vitamin D activated?
by liver and kidney
what are the functions of vitamin D?
- Essential for bone health (important for calcium absorption)
- Helps regulate Insulin formation and secretion
what are sources of vitamin D?
- exposure to sunlight
- fortified foods (milk, cereals)
- oily fish, egg yolk, liver
- supplements
what happens with vitamin D deficiency and toxicity?
- deficiency: rickets in children, osteomalacia and osteoporosis in adults
- toxicity: hypercalcemia
what are the different forms of vitamin E?
- 8 similar compounds but only alpha-tocopherol required for humans
what are the functions of vitamin E?
- antioxidant (protect cell membrane form free radicals)
what is the recommended daily intake of vitamin E?
- 15mg/day for adult
- 19mg/day for breastfeeding
what are food sources of vitamin E?
-nuts/seeds
- vegetable oil
- whole grain/wheat germ oil
- fruits and vegetables
- animal products
when does vitamin E deficiency occurs? what about toxicity?
- deficiency: occurs with fat malabsorption or rare genetic disorders
- toxicity: nontoxic and adverse effects have not been found, but can interfere with blood clotting and causes lung injury when inhaled
what are the forms of vitamin K?
K1 and K2
what are the functions of vitamin K?
- blood clotting (necessary for the synthesis of thrombin)
- bone health
what are the dietary recommendations of vitamin K?
- men: 120 mg/day
- women: 90 mg/day
what are the food sources of vitamin K?
- green vegetables
- plant oils
- intestinal bacteria
what happens with vitamin K deficiency and toxicity?
- deficiency: rare in healthy people, newborns at risk
- toxicity: rare, can interfere with anticoagulant medications
what are the functions of thiamin (B1)?
- coenzyme in energy metabolism
- part of the coenzyme thiamin pyrophosphate (TPP): helps break down glucose, make RNA/DNA, helps power protein, help synthesize and regulate neurotransmitters
what is the name of vitamin B1?
thiamin
what are dietary recommendations of thiamin (B1)?
- men: 1.2 mg/day
- women: 1.1 mg/day
- pregnancy: 1.4 mg/day
- breastfeeding: 1.5 mg/day
what are the food sources of thiamin (B1)?
- pork
- legumes/nuts/seeds
- fish/seafood
- grain product
- cooking reduces content
what happens with thiamin (B1) deficiency and toxicity?
- deficiency: beriberi (overall profound muscle weakness and nerve destruction – milder symptoms include headache, irritability, depression, and loss of appetite)
- toxicity: no reports of toxicity
what is the name for vitamin B2?
riboflavin
what are the functions of riboflavin (B2)?
-coenzyme in energy metabolism
- supports antioxidants
what are the food sources of riboflavin (B2)?
- milk/dairy products
- enriched grains
- eggs
____ breaks down riboflavin which is why ___________
- light
- foods high in riboflavin are stored in opaque containers (like milk)
what happens with riboflavin deficiency and toxicity?
- deficiency: ariboflavinosis (occurs mostly in chronic alcoholism)
- skin disorders, hyperemia (excess blood) and edema of the mouth and throat, angular stomatitis (lesions at the corners of the mouth), cheilosis (swollen, cracked lips), hair loss, reproductive problems, sore throat, itchy and red
- toxicity: no reported cases
what are the functions of niacin (B3)?
- coenzyme in energy metabolism
- supports fatty acid synthesis
what is the name for vitamin B3?
niacin
what are the food sources of niacin (B3)?
- can be made from tryptophan
- whole and enriched grains
- meat, poultry, fish, nuts, and peanuts
what happens with niacin (B3) deficiency and toxicity?
- deficiency: pellagra (dermatitis, diarrhea, dementia, and death) and can worsen if also deficient in B1, B6 and iron
- toxicity: high doses used to treat high blood cholesterol (skin flushing, liver damage)
what is the name of vitamin B6?
pyridoxine
what are the functions of pyridoxine (B6)?
- PLP coenzyme in protein and AA metabolism, and gluconeogenesis
- produce non-essential AA
- produce neurotransmitters and hemoglobin
- helps to lower blood levels of homocysteine
what are food sources of vitamin B6?
- meat,fish, poultry, fortified meat substitutes
- bananas
- sunflower seeds
what happens with vitamin B6 deficiency and toxicity?
- deficiency: microcytic hypochromic anemia, heart disease (high homocysteine), damage nervous system (depression, headache, confusion, convulsion)
- toxicity: can cause subtle neurological damage, upset stomach, headache, sleepiness, tingling/prickling/burning sensation
what are the functions of folate (B9)?
- coenzyme in DNA synthesis and cell division
- coenzyme in AA metabolism
- needed for normal RBC maturation
- works with B6 and B12 to help control homocysteine levels
what is the name for vitamin B9?
folate
what are the food sources of folate (B9)?
- fortified cereals/enriched grains
- green leafy vegetables
- orange juice
- sunflower seeds
- legumes
what happens with folate (B9) deficiency and toxicity?
- deficiency: anemia and diarrhea, birth defects (spina bifida), heart disease
- toxicity: can mask vitamin B12 deficiency with folate supplements, hypersensitive people may suffer hives or respiratory distress
what is the name of vitamin B12?
cobalamin
what are the sources of vitamin B12?
- only animal foods: meats, liver, milk, eggs
- fortified foods
what are the functions of vitamin B12?
- needed for normal folate function (DNA and RBC synthesis, metabolize homocysteine)
- maintain myelin sheath around nerves
vitamin B12 absorption requires __________
intrinsic factor
what happens with vitamin B12 deficiency and toxicity?
- deficiency: can lead to pernicious anemia (resulting in nerve damage), RBCs can look enlarges
- toxicity: none
what are the functions of vitamin B5?
- component of coenzyme A
what are the food sources of vitamin B5?
- widespread in food
- reduced by freezing, canning, and refining
what happens with vitamin B5 deficiency and toxicity?
rare
what is the name of vitamin B7?
biotin
what are the functions of biotin (B7)?
- coenzyme
- AA metabolism
- fatty acid synthesis
- release of energy from fatty acids
- DNA synthesis
what are the food sources of biotin (B7)?
- cauliflower
- liver
- peanuts
- cheese
- raw egg whites binds biotin and prevents absorption
what are the functions of vitamin C?
- antioxidant
- collagen synthesis
- enhances the absorption of iron from plant foods
- make other essential compounds
what are the food sources of vitamin C?
- fruits (citrus, strawberries, kiwi)
- vegetables: broccoli, tomatos, potatoes, cabbage, leafy green, peppers
what happens with vitamin C deficiency and toxicity?
- deficiency: scurvy
- toxicity: may cause GI distress in high doses
