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MCT Exam 2 > Vitamins I and II > Flashcards

Vitamins I and II Flashcards

1
Q

Nutrients definition

A

things you need to bring into your body to have normal physiological function

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2
Q

Organic macronutrients

A

required in large amounts; sources of energy and structural elements; CARBS, FATS, PROTEINS

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3
Q

Micronutrients

A

required in small amounts; not used for energy or structures; VITAMINS (organic compound), MINERALS (inorganic compounds)

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4
Q

How are micronutrients acquired?

A

Must be absorbed through diet, body cannot make them

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5
Q

What are the Fat-soluble Vitamins?

A

A, D, E, K

ADE-K

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6
Q

What are characteristics of Fat-Soluble Vitamins?

A

ACT LIKE FATS; structure based on isoprene units; uptake is in small intestine along with dietary fats; stored in liver or adipose; transported throughout body in chylomicrons and lipoproteins; deficiencies can arise in people with problems absorbing fats

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7
Q

Large doses of Fat-Soluble Vitamins can be hazardous because…

A

They are stored. Stored in liver and adipose, can reach toxic levels

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8
Q

In patients with problems digesting fats (problem with pancreas [lipase] or bile production [emulsification])…

A

They will have trouble absorbing fat-soluble vitamins

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9
Q

What are the Water-Soluble Vitamins?

A 
Niacin
Riboflavin
Pantothenic Acid
Thiamin
Folate
Vit B12
Vit B6
Biotin
Vit C
(B Vitamins + C)
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10
Q

Characteristics of Water-Soluble Vitamins?

A

Taken up by diffusions or mediated transport in small intestine; little storage of these vitamins - excreted in urine; not true for B12

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11
Q

Vitamin B12 is an anomalous water-soluble vitamin because…

A

does not act like water-soluble vitamin; stored in the body; uptake is different than other WS vitamins

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12
Q

Potential causes for vitamin deficiency in developed countries

A
  • Anorexia
  • Bariatric surgery
  • Problems with digestion
  • Malabsorption (diarrhea, pancreatic problems, small intestine)
  • Increased need (pregnancy, lactation, infection)
  • Alcoholism (malnutrition or reduced thiamin)
  • Smoking (reduces Vit C and E conc)
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13
Q

Why can alcoholics be vitamin deficient?

A

Can sustain themselves with alcohol because it is high calorically;
Ethanol inhibits absorption of Thiamin;
Ethanol competes with enzymes needed by vitamin A

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14
Q

Common signs of vitamin deficiency

A
  • Dermatitis
  • Anemia
  • Neuropathy
  • Muscle weakness
  • Fatigue
  • Decreased appetite, growth, immunity
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15
Q

What are the B vitamins?

A 
Thiamin (B1)
Riboflavin (B2)
Niacin (B3)
Pantothenic acid (B5)
B6
Biotin
Folate
B12

(T1R2aiN3)

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16
Q

Coenzyme definition

A

organic molecule necessary for catalysis (apoenzyme and coenzyme = holoenzyme); required for catalysis, without the coenzyme it does not work

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17
Q

Most common function of vitamins are?

A

Acting as coenzymes

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18
Q

B vitamin coenzymes

A
  • Niacin - NADH, NADPH
  • Riboflavin - FADH2, FMNH2
  • Pantothenic acid - CoA, ACP
  • Thiamin - thiamin pyrophosphate (TPP)
  • Biotin - biotin
  • B12 - cobalamin derivatives
  • Folate - tetrahydrofolate
    B6 - pyridoxal phosphate
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19
Q

Niacin (B3)

A

Found in grains and meats but often not released during digestion.
Deficiency causes Pellagra (4 D’s - dermatitis, diarrhea, dementia, death).
Diets based on corn can cause Pellagra

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20
Q

Riboflavin (B2)

A

Part of FAD and FMN; FADH2 formed from breakdown of fuels (TCA, FA oxidation);
FMN - accepts electrons from NADH as a coenzyme in Complex 1 of ETC;
In meat, dairy, dark green veg;
Deficiency isn’t big problem, when deficient it affects tissues of mouth

21
Q

Pantothenic acid (pantothenate)

A

Found in all plant and animal based foods;
deficiency extremely rare;
Part of CoA and ACP (contains sulfhydryl group that forms high energy bonds)

22
Q

Thiamin (B1)

A 
Thiamin pyrophosphate (TPP);
TPP is part of PDH and a-ketoglutaric dehydrogenase;
found in variety of plant and animal based foods (whole grains have most)
23
Q

Thiamin deficiency diseases

A
  • alcoholics = Wernicke-Korsakoff Syndrome - combination of Wernicke’s encephalopathy and Korsakoff psychosis;
  • chronic defic = Dry beriberi -older adults, wasting/weakness in legs, peripheral neuropathies;
  • acute defic = Wet beriberi - edema and heart failure
  • infantile beriberi - death from heart failure occurs within hours
24
Q

Biotin

A

found in most foods;
deficiency is rare;
coenzyme for ATP-dependent carboxylases;
important for gluconeogenesis and FA synthesis

25
Q

Vitamin B12 (cobalamin)

A

Main process B12 is important for is S-adenosylmethionine (SAM) = important for methylation of lipids in myelin;
coenzyme in oxidation of odd-chain FA;
methionine synthesis for homocysteine

26
Q

Vitamin B12 is found in…

A

Only found in animal products (comes from bacteria in animals);
Can be stored in live for a significant amount of time;
Vegans/vegetarians can be deficient

27
Q

Intrinsic Factor

A

made in parietal cells of stomach; binds B12 in stomach and move together into the intestines and get absorbed together through mediated endocytosis;
No IF = problem absorbing B12

28
Q

B12 deficiency

A

can cause anemia and neurological symptoms due to absorption defects (because stomach has been removed, parietal cells fail to make IF, or problems with small intestine);
Pernicious (deadly) anemia - caused by lack of intrinsic factor due to gastritis from autoimmune attack of parietal cells

29
Q

Folate (folic acid), also found in…

A

Folate’s active form is tetrahydrofolate (FH4);
important in synthesis of purines, thymine, methionine;
green vegetables, mushrooms

30
Q

Folate (folic acid) deficiency

A

Deficiency around the time of conception causes around 50% of neural tube defects;
spina bifida - exposed spinal cord, often some paralysis;
anencephaly - reduced brain tissue;
(fortification of cereal so if a woman got pregnant there wouldn’t be a severe folate deficiency)

31
Q

T or F: 70% of methyl-tetrahydrofolate in cells needs to be converted by vitamin B12 into its active form

A

TRUE

32
Q

Deficiency in either B12 or Folate can cause…

A

Anemia;

Treatment with folate can overcome anemia from folate or B12 deficiency

33
Q

Vitamin B6 (pyridoxine)

A

coenzyme for a lot of enzymes (transfers small groups);
associated with amino acid biosynthesis and catabolism;
needed to make neurotransmitters - serotonin, epi, norepi, GABA

34
Q

Vitamin K (koagulation)

A

Green leafy vegetables, made by bacteria in gut;

newborns susceptible to deficiency (given supplement);

35
Q

Vitamin K (koagulation) coenzymes

A

coenzymes = phylloquinone, menaquinone;
Vit K dependent carboxylase = allows clotting factors to bind Ca which allows them to bind phospholipids on platelets and endothelial cells

36
Q

Vitamin K and Warfarin (coumadin)

A

patients taking warfarin need to maintain a steady amount of vitamin K in diet

37
Q

Vitamin A (retinol) found in…

A

Eggs, milk, meat;

B-carotene (provitamin A) is in green, orange, and yellow vegetables and fruits;

38
Q

Retinoic acid (active form of Vit A)

A

hormone-like molecule that promotes epithelial differentiation;
important for growth;
deficiency can cause scaly skin and keratinization of cornea

39
Q

Retinal (Vitamin A)

A

coenzyme for vision;
in rods and cones, attached to visual pigment protein;
when light hits - G protein activated, phosphodiesterase activated, cGMP decrease, channel closes

40
Q

Retinal deficiency

A

most common cause of blindness in the world;

1st night blindness (rhodopsin), corneal damage (keratinization of cornea), blindness

41
Q

Vitamin D (calcitrol) found in…

A

fish, egg yolks, fortified milk;

If exposed to enough sun, do not need to acquire through diet

42
Q

Vitamin D (calcitrol) acts …

A

Acts as a hormone when low Ca in plasma, causes intestine to absorb calcium, activates osteoclasts (PTH), and causes kidney to increase resorption of calcium (with PTH), binds nuclear vitamin D receptor

43
Q

Vitamin D (calcitrol) deficiency

A

lack of UV light and lacking in diet;
rickets (children - softening of bones, bowing of leg bones);
osteomalacia (adults - increased fragility of bones);
deficiency becoming more common (less milk consumption, less exposure to sun

44
Q

Vitamin C (ascorbic acid) found in…

A

broccoli, bell peppers, citrus fruit, spinach, tomatoes

45
Q

Vitamin C (ascorbic acid) acts as

A

Antioxidant for cytoplasm and interstitial fluid;
Boots many aspects of immune function;
important for maintenance of collagen;

46
Q

Vitamin C (ascorbic acid) deficiency

A

Scurvy - capillary fragility due to defective collagen;

bleeding gums, hemorrhages under the skin, joint pain, delayed wound healing

47
Q

Vitamin E found in

A

vegetable oils, nuts, animal fats;

deficiency is rare

48
Q

Vitamin E functions as

A

antioxidants for lipids; active form a-tocopherol

49
Q

Dietary reference intakes

A

EAR - estimated average requirement
RDA - recommended dietary allowance
AI - adequate intake
UL - upper intake level

MCT Exam 2 (8 decks)

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