Vitamins Flashcards
fat soluble vitamins
A, D, E and K
Clinical significant relevance of distinguishing fat soluble vitamins and water soluble vitamins
conditions which impair absorption of fat such as digestion problems : cystic fibrosis, gull stone and intestinal disease: celiac disease, Crohn’s disease causes vitamin difficiencies
water soluble vitamins
C &B complex vitamins
what is vitamin
an essential nutrient not used for energy production
what is difference between vitamins and Minerals
Vitamins are organic molecules, complex molecules containing carbon
Minerals, are non organic
Cornea
clear membrane on the anterior aspect of the eye, transmits light to the retina
Retina
layer of nerve cells and receptors on the posterior part of the eye - detects light and turns ti into electrical signals
Cellular differentiation
process by which cells mature and become specialized for their particular function
Dietary role Vitamin A
Vision: important for function of the retina and the cornea
Epithelium: important for cellular differentiation
Bone: regulates functions of osteoclasts, which remodel bone structure
General signalling an active form of vitamin A (retinoic acid) serves as a signal that regulates the functions of a wide variety of cells (immune, skin, bone)
Forms of vitamin A
Active forms: retinol, retinal - found in animal products
Precursor forms: beta-carotene-orange pigment found in animal sources of vitamin A
Dietary source of Vitamin A
Bright orange and darck green: Carrots, pumpkin, sweet potatoes, mangoes, apricots, spinach, broccoli, bok choy
Animals: liver, daily products, fish oil, eggs
Vitamin A dificiency
Visual: retina - night blindness,
cornea- progressive drying and opacification (clouding) that can result in permanent blindness -xeropthalmia
Epithelial cracking and hardening of skin, poor development of epithelial membranes
Immune: impaired immunity, infections
Bone and growth: failure to grow, reduction of enamel, Xerophalmia
mostly aected in 3rd world in energy deficient malnutrition. Severe vitamin A dificiency - visual symptoms and diarrhea milder vitamin A dificiency - poor function of the immune system
Vitamin A toxicity
Most toxic vitamins
Acute: from ingestion of foods very high in vitamin A such as polar bear liver, nausia, vomiting, diarrhea joint pain, headache, blurry vision, muscle and abdominal pain
Chronic: from elevated supplement intake, bone loss, liver damage, hair loss, dry skin, weight loss, anemia
neurological sypoms
Excess vitamin a during pregnancy is linked to serious birth defects
Vitamin D
Act as biochemical signal
Different forms: main ones vitamin D2 (only in plants) and D3
D3 converted to calcidiol in the liver, which is convereted to calcitrial (active) in kidneys
Skin can sythesize from a steroid precursor when exposed to UV light
Vitamin D dietary role
Bone: Stimulates intestinal uptake of calcium and phosphate
Works with PTH to reduce renal loss of calcium
Other stimulates the maturation of a range of cells, including those of the immune system
Evidence is building that it reduces the risk of cardiorespiratory and autoimmune disease as well as some cancers
Vitamin D sources
Sunlight The sun transforms 7 -dehydrocholesterol into cholecalciferol
The liver stores cholecalciferol and converts it into calcidiol
The kidneys convert calcidiol to calcitriol (active form of vitamin D)
Food: found almost exclusively in animal products
Fortified milk fish, other seafood liver
Vitamin D dificiency
Rickets: childhood disease, development of softened, malformed bone
Rickets: bowed legs, beaded ribs, protruding belly
Osteomalacia: resulting in spine abnormalities, fractures and sore bones and muscles
Vitamin D dificiency contributes to osteoporosis and many others heart disease, stroke, etc.
Vitamin D toxicity
High doses of vitamin D show significant toxicity
Acute: hypertension, kidney failure, muscle weakenss, elevated serum calcium
Chronic: calcification in soft tissues, kidney failure, plus siminar to acute.
Toxicity is not caused by excessive sunlight or food, but always over prescription of D supplements
vitamin D RDA
Children 10 ug/day
Adult 15ug/day
Oder than 70 20ug/day
Has been suggested by some that higher intakes may help combat chronic disease
Tolerable upper intake
Infants 25 ug/day All others 50 ug/day
2 cups of milk or 3 oz of salmon provide a RDA. Toxic dose is 1 kg of salmon each day
Vitamin E
Part of a family of molecules konw as tocopherols
Many tocopherols exist however only one alpha tocopherol is retained by the body
Vitamin E is an antioxidant
Antioxidants
Most important : vitamin C and E
antioxidants dispose of chemicals known as free radicals. Free radicals are capable of damaging a wide range of molecules in cells
Antioxidants neutralize free radicals.
Free radical
molecule with an unpaired electron, highly reactive. Free radicals do the most damage to DNA and protein.
Vitamin E dietary role
Thought to be important in preventing oxidation of membrane phospholipids by free radicals
This proection is key for normal red blood cell, immune, nervous system, and respiratory function
Cooperate with Vitamin C to combat oxidation
Vitamin E dietary source
Widespread in vegetable foods
Significant amounts in cold pressed vegetable oil (canola, safflower, sunflower, wheat germ) 5 or so table spoon provides RDA levels
Vitamin E dificiency
Rare in health adults - symptoms include nervous system disorders (loss of coordination, imparied vision) Can be seen in premature infats, though - hemolysis of red blood cells is the prominent feature
vitamin E toxicity
Among the least toxic vitamins
Chronic high doses may increase mortality
May increase bleeding risk
high doeses of supplements slightly icrease risk of mortality
Vitamin E RDA
RDA 15 mg/day
Tolerable upper intake: 1000 mg/day
Higher levels recommended in smokers and with diets high in polyunsaturated fats
Vitamin K dietary role
Key for sysnthesis of clotting factors II, VII, IX, X
Also key for synthesis of proteins C and S, which limit clotting.
Bone formation : involved in synthesis of proteins that regulate bone deposition
vitamin K sources
Dark green leafy vegetable
Food cabbage family, begetable oils (canola, olive)
Bacteria in the colon also synthesize vitamin K
Animal milk eggs and liver
Most vit. K is provided by dietary intake for bones, rather than colonic bacteria for clotting factor
vitamin K dificiency
Deficiency only common ong newborn. All infants receive vitamin K supplementation after birth
Deficiencies in adults are due to lack of intestinal bacteria (by sterilizing with antibiotics) or inability to absorb fat-soluable vitamins
Symptoms include hemorrhage, bone malformation, and increased likelihood of hip fracture (in adults).
Vitamin K toxicity
Rare, only causey overenthusiastic supplementation
Jaundice (yellowing of the skin and sclera) from hemolysis as well as release of bilirubin from the liver
Bilirubin is a by-product hemoglobin metabolism, and is sorted in the liver
Vitamin K RDA
RDA 90-120 ug/day
Tolerable upper level : not yet assigned, toxicity is very rare
Fat soluble and water soluble
Most fat soluble store in liver for months worth amount except Vitamin K
water soluble has very small body stores except Vitamin B 12 (cobalamin)
Vitamin C
AKA Ascorbic Acid usually acts as an antioxidant, but very high does can have pro-oxidant effect
Vitamin C dietary role
Anti-oxidant: regenerates other antioxidants and removes free radicals
Important in normal collagen synthesis
Invovled in synthesis of amine neurotransmitters (dopamine, norepinephrine, seotonin)
Vitamin C sources
various fruits and vegetable, citrus fruit, poppers Brussels sprouts broccoli, potatoes (sweet and regular)
Vulnerable to heat and exposure to oxygen
Vitamin C dificiency
Scurvy: lof appetite, sensitivity to touch, weakness, bleeding gums and mucous membranes loose teeth, petechiae, poor wound healing anemia
Due to problems in collagen synthesis, except for anemia (impaired iron absorption is responsible)
mega dose possibly benefit cold, cancer, cataracts, atrosclerosis
Vitamin C toxicity
toxicity is minimal, kidney stones in those with poorly functioning kidneys, indigestion dirrhea,
incredibly non-toxic
Vitamin C RDA
75-90 mg (about 40 mg higher for smokers)
Tolerable upper limit 400 mg for children, 2000 mg for adults
1 cup of orange juice 120 mg
1 cup of Brussels sprouts 100 mg
1 cup strawberries 80mg
1cup of sweet potato 40 mg
300 g of baked red potato 30 mg
Vitamin B1 Dietary role
Vit. B are coenzymes-binds with enzymes and aenzyme function
participate in energy metabolism Thiamine (B1), roboflavin (B2), niacin (B3), pantothenic acid, and biotin all participate in chemical reactions that liberate chemical energy from food
Vitamin B1 sources
Thiamine: enriched and whole wheat grains, meats, legumes, seeds
Riboflavin same as thiamine and dairy, liver and spinach
Niacin: meats enriched and whole wheat cereals
Vitamin B1 deficiency
Thiamine deficiency - hystorically known as beriberiresults in peripheral neuropathy, weakness, edema, and heart dysfunction
Niacin deficiency - known as pellagra. For D’s: diarrhea, dementia, dermatitis, and eventually death
Thiamine deficiency and niacin deficinecy often go hand in hand, typically in malnourished alcoholics. In this case, the neurological, heart and skin manifestations of disease prodominate
Vitamin B12 dietary role
Folate and B12 (cobalamin) are crucial for cell division and nucleotige synthesis.
Vitamin B6 participate in wide range of chemical reactions, including convertion of amino acids to other amino acids
Vitamin B12 sources
Folate: liver, legumes, enriched cereals, asorted vegetables, (beets, asparagus, avocado)
B12: liver, meats dairy products, relatively low levels in plants:
Vegetarians can eat soy products, fresh (from garden) veggies, enriched cereals
vitamin B12 deficiency
Folate- main complication of deficiency is anemia
B12 deficiency exhibits anemia that is indistinguishable form folate deficiency anemia. however, with time a peripheral motor and sensory neuropahy can develop, which may be irreversible.
Often folate and B12 deficiency go hand in hand. Treating a folate deficiency can mask the symptom of B12
what is mineral
an essential nutrient not used for energy production
minerals are simple chemicals, usually only one atom that exists as an ion (charged particle). Vitamins have a much more complex carbon-based structure
how are minerals categorized?
major minerals - more than 5 g present in the body
Trace minerals - less than 5 g present in the body
Which minerals are in the body?
Calcium and phosphorus are by far the most abundant minerals (1.7 kg)
Followed by potassium, sulfur, sodium, chloride and magnesium
About 2.5 kg of minerals in an adult make
