Vitamins (C) Flashcards
How many known vitamins are there?
13
Which chronic malabsorption disease can cause deficiencies of fat-soluble vitamins?
Cystic fibrosis, celiac disease, and Crohn’s disease
What is the name for vitamin compounds that have different chemical forms but the same purpose?
Vitamers
When are fat soluble vitamins lost?
When mineral oil is ingested
What are the functions of vitamin A?
Maintain vision, bone growth, reproduction, cell division, and a healthy immune system
What are the names of carotenoids?
Beta-carotene, lutein, lycopene, zeaxanthin
What are good sources of carotenoids?
Orange and green vegetables (Carrots, sweet potatoes, spinach, broccoli, pumpkin, squash, mango, canteloupe)
What are good sources of retinol?
Fat-containing animal foods
Which effect of carotenoids is not shown to be achieved with supplements?
Anti-cancer effects
What is a retinol equivalent?
3.33 IUs. 1 mcg retinol or 6mcg beta-carotene
What are the signs and symptoms of hypervitaminosis A?
Birth defects, hair loss, dry skin, liver damage, headaches, and nausea
What are the signs and symptoms of vitamin A deficiency?
Night blindness, dry skin, weakened immune system, xerophthalmia
Where is vitamin D2 (ergocalciferol) found?
In plants
How is vitamin D3 (cholecalciferol) made?
Synthesized through cholesterol in the skin
What is vitamin D classified as?
Prohormone
What are the functions of vitamin D?
Promotes calcium and phosphorus absorption/bone and tooth mineralization, and prevents tetany. Also plays a part in cell growth, immune and neuromuscular function, and reduces inflammation
Where is vitamin D absorbed and converted?
Absorbed in intestines, changed in the liver and kidneys
How much vitamin D does cow’s milk provide?
100IU per cup
What is the DRI for vitamin D?
600 IUs / 15 mcg
What are the signs and symptoms of hypervitaminosis D?
Calcium deposits in soft tissue, kidney and heart damage, and bone fragility
What is the TUL for vitamin D?
4,000 IUs
What is the vitamin D requirement for children ages 0-12 months?
400 IUs
What is the vitamin D requirement for seniors older than 70?
800 IUs
What are the signs and symptoms of vitamin D deficiency?
Inhibited calcium and phosphorus absorption, rickets, osteomalacia and osteoporosis
Who is most at risk for vitamin D deficiency?
Breastfed infants
What percent of the US population is deficient in vitamin D?
40-75%
What is the optimal blood level for vitamin D?
> .30 mg/dL (previously thought to be >.20 mg/dL)
What compounds are classified as vitamin E?
Tocopherols (alpha, beta, delta, and gamma), and tocotrienols
Which is the most bioactive form of vitamin E?
alpha-tocopherol
What is vitamin E classified as?
An antioxidant (helped by vitamin C and selenium, boosts immune system)
What carries vitamin E through the blood?
Lipoproteins
When vitamin E levels are low, red blood cells become vulnerable to what?
Higher rate of hemolysis (destruction)
What does vitamin E prevent in infants?
Hemolytic anemia
What is the commercial use of vitamin E?
Prevent spoilage (antioxidant)
What are good sources of vitamin E?
Vegetable oils, wheat germ, nuts, and leafy greens
Vitamin E requirement increases with increased intake of what?
Polyunsaturated fat
Who is at risk for vitamin E deficiency?
Premature, underweight infants and those with fat malabsorption
What are the signs and symptoms of vitamin E deficiency?
Neurological defects in children– takes 5-10 years to show for adults
Where is vitamin K1 (phylloquinone) found?
Leafy greens and meat
Where is vitamin K2 (menaquinone)
Meat, and synthesized in intestine by bacteria
What is synthetic vitamin K called?
Menadione
What is vitamin K destroyed by?
Light and alkalies
What protein does vitamin K form?
Prothrombin (properly clots blood)
Newborns not given vitamin K are at risk for what?
Intracranial hemorrhage
Which milk is the best source of vitamin K?
Cow’s milk
When may vitamin K be given?
With fat malabsorption, after extensive antibiotic therapy, or to treat hemorrhage/anticoagulant overdose
How often must vitamin K be ingested?
Daily (used immediately)
What are water-soluble vitamins are easily destroyed by what?
Light, air, and cooking
What systems does beri-beri effect?
Nervous, cardiovascular, and GI
What are the symptoms of beri-beri?
Heavy legs, burning feet, atrophy, irritability, headaches, constipation, tachycardia, edema, and heart failure
Thiamine is classified as what?
Coenzyme
What is thiamine lost to?
Water, and partially to heat and alkalies
What are the functions of thiamine?
Metabolizes carbs and some proteins and is essential to nerve and muscle function
What are good sources of thiamine?
Grains, pork, liver, nuts, seeds, and legumes
When does the DRI for thiamine increase?
With increased calorie consumption
What are the symptoms of thiamine deficiency?
Anorexia, fatigue, irritation, and constipation
Who is at risk for thiamine deficiency?
Alcoholics, dialysis patients and those who have undergone bypass surgery, and those on a diet of all or mostly rice
What food contains thiaminase (inhibits thiamine absorption)?
Raw fish
What is riboflavin lost to?
Light and irradiation, and unstable in alkalies
What are the functions of vitamin B2 (riboflavin)?
Metabolizes macronutrients and maintains lip and eye health.
What are the best sources of riboflavin?
Widely distributed, but milk, meat, grains, and some green veggies
What are the DRIs for riboflavin?
1.1mg women, 1.3mg men (increases with energy expenditure)
What are the symptoms of riboflavin deficiency?
Cheilosis, glossitis, dermatitis, eye strain and fatigue
What can decrease riboflavin absorption?
Fiber laxatives
What must milk be stored inside in order to preserve B2?
Opaque containers
What is niacin (nicotinic acid and nicotinamide) classified as?
A coenzyme in energy metabolism and a cell constituent
What are the best sources of niacin?
Meats, peanuts and legumes. Dairy and eggs have tryptophan (precursor)
Niacin can be used clinically for what?
Cholesterol lowering
What are the symptoms of hypervitaminosis niacin?
Flushing due to vascular dilation, GI problems, liver damage and peptic ulcers
What are the signs and symptoms of niacin deficiency (often co-occurring with riboflavin)?
Weakness, anorexia, indigestion, and irritability. In extreme cases, pellagra: sores, diarrhea, poor memory, and death
What is B6 (pyridoxine, pyridoxal, and doxamine) sensitive to?
Light and alkalies
What are the functions of pyridoxine (B6)?
Metabolizes protein, converts glycogen to glucose, and converts amino acids (tryptophan, neurotransmitters)
What are the best sources of B6?
Poultry, fish, organs, potatoes, bananas, spinach, and whole grains
When does the DRI for B6 increase?
With increased protein intake
What medication interferes with B6 absorption?
Oral contraceptives (birth control)
Which vitamin is required to manufacture nonessential amino acids?
B6 (pyridoxine)
What are the symptoms of vitamin B6 deficiency (often co-occurring with other B vitamins)?
Irritability, depression, dermatitis; in infants, neurological and abdominal problems
Although rare, what can vitamin B6 toxicity cause?
Temporary neurological problems
Which vitamin compound contains the mineral cobalt?
B12 (cobalamin)
What are vitamin B12 (cobalamin) sensitive to?
Light and alkalies
How long is vitamin B12 stored in the body?
3-5 years
What are the functions of vitamin B12?
Metabolizes folate and maintains the myelin sheath and healthy red blood cells
Which steps of absorption does vitamin B12 follow?
Binds with glycoprotein intrinsic factor in stomach, combines with pancreatic proteases in small intestine, and binds to receptors in the ileum
Lack of the intrinsic factor necessary to absorb B12 can cause what type of anemia?
Pernicious anemia (severe and chronic)
When does the DRI for B12 increase?
With pregnancy and lactation
How are rare and congenital B12 absorption problems addressed?
Intramuscular injections
Inadequate intake of B12 can cause which type of anemia?
Megaloblastic anemia (large, juvenile RBCs)
What are the symptoms of B12 deficiency?
Nervous system damage, mouth issues, pallor, neurological upsets, and weight loss?
What are the functions of folate/folacin/folic acid?
Synthesize DNA, metabolize protein, and form hemoglobin
What cancers does folic acid prevent?
GI and cervical cancer
Folate raises blood levels of which amino acids?
Homocysteine (prevents stroke, blood vessel disease, macular degeneration, and Alzheimer’s)
What are the best sources of folate?
Fortified cereal, vegetables, legumes, sunflower seeds, and fruit
What percent of folate is lost during cooking and food production?
50-90%
The DRI for folate is higher for what demographic?
Women of child-bearing age (600mcg)
What are the symptoms of folic acid deficiency?
(Neural tube defects in pregnant) mouth inflammation, poor growth, mental issues, nerve issues, and megaloblastic anemia
What amount are OTC folate supplements limited to?
100mcg infants, 300mcg children, and 400mcg adults
What is the concern with excessive folate?
Can mask B12 deficiency and may inactivate epilepsy medication
What is biotin (vitamin H) classified as?
A coenzyme in the synthesis of fatty and amino acids
What are the best sources of biotin?
Egg yolks, dairy, lean meat, broccoli, spinach, and cauliflower
Where is biotin endogenously synthesized?
Colon (unknown amount)
What are the symptoms of biotin (H) deficiency?
Nausea, anorexia, depression, pallor, dermatitis, and increased serum cholesterol
Although it is stable, pantothenic acid is damaged by what?
Acids and alkalies
What are the functions of pantothenic acid?
Metabolizes macronutrients and forms steroids as well as acetylcholine
When produced in a lab, what were the symptoms of pantothenic acid deficiency?
Weakness, fatigue, and burning of feet
What is vitamin C (ascorbic acid) classified as?
An antioxidant
Vitamin C (ascorbic acid) is lost to what?
Heat, air, alkalies, and in water
What are the functions of vitamin C?
Prevents scurvy, forms collagen, is necessary for wound healing, and aids in nonheme iron absorption. Also forms norepinephrine, some amino acids, folate, leukocytes, and regulates immune system and allergic reactions
Where is vitamin C absorbed?
The small intestine
How does vitamin C reduce the risk of some cancers?
Reducing nitrates
When does the DRI for vitamin C increase?
In smokers (125mg) and with trauma
What are the symptoms of hypervitaminosis C?
GI problems, oxalate kidney stones, and rebound scurvy if excess is stopped abruptly
Vitamin C should not exceed what percent of the DRIs in multivitamins?
100%
