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Nutrition > Unit 5: Vitamins > Flashcards

Unit 5: Vitamins Flashcards

(71 cards)

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1
Q

What are the two classes of vitamins?

A

Fat soluble and water soluble

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2
Q

What are the fat soluble vitamins?

A

A,D, E and K

Needed in periodic doses (weekly or monthly) because body can draw on its stores

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3
Q

Where are fat soluble vitamins stored?

A

Can be stored in the liver or with other lipids in fatty tissues and can build up to toxic amounts.

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4
Q

What are the functions of vitamin A?

A

Versatile.

Gene expression, vision, cell differentiation, reproduction and growth, immunity

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5
Q

How much vitamin A can the body store?

A

One year’s supply

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6
Q

What does vitamin A deficiency cause?

A

Preventable blindness in children.
Keratin is produced instead of epithelial cells (keratinization)
More susceptible to infection due to drying and hardening of salivary glands
Takes about a year for symptoms to appear due to storage capacities

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7
Q

What happens during vitamin A toxicity?

A

Occurs from supplements
Chronically, can weaken bones and contribute to hip fractures.
Malformations of fetus in pregnant women.
Children are most sensitive

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8
Q

What is vitamin A’s role in vision?

A

Helps maintain a healthy, crystal clear cornea

Participates in light detection in the retina

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9
Q

What is night blindness?

A

A symptom of vitamin A deficiency

Difficulty adapting to changing light levels

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10
Q

What are some sources of vitamin A and beta-carotene?

A 
1 cup fortified milk
1/2 cup carrots, sweet potato, spinach, bok choy
3 apricots
3 oz beef liver 
for 10% or more daily value
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11
Q

How is vitamin D formed?

A

UV light from the sun converts a cholesterol compound on the skin into a precursor that is directly absorbed into the blood. The liver and kidneys then finish converting it to active vitamin D.

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12
Q

What are the functions of vitamin D?

A

Hormone

Plays a role in regulating blood calcium and phosphorous levels to maintain bone integrity, bone growth

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13
Q

Research shows that low vitamin D levels may be linked to what problems?

A

High blood pressure, cancer, type 1 diabetes, heart disease, rheumatoid arthritis, inflammatory bowel disease and MS.

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14
Q

What can vitamin D deficiency cause?

A

Rickets (children) where bones fail to calcify normally causing growth retardation and skeletal abnormalities (bendy bones, bowed legs)
Osteomalacia (adults) in which there is poor mineralization of bones
Osteoporosis

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15
Q

How does vitamin D raise blood concentrations of bone minerals?

A

When diet is insufficient, it can enhance absorption from the GI tract, reabsorption by the kidneys and mobilization from the bones into the blood.

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16
Q

What are some factors that contribute to vitamin D deficiency?

A

Dark skin, breastfeeding without supplementation, lack of sunlight and not using fortified milk

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17
Q

Which vitamin is most likely to have toxic effects when consumed in excess?

A

Vitamin D

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18
Q

What are the effects of vitamin D toxicity?

A

Excess calcium concentration in the blood which tends to precipitate in soft tissues and form stones (kidneys)
Can also calcify blood vessels
Caused by supplements

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19
Q

Is sunlight a risk factor for vitamin D toxicity?

A

No. Prolonged exposure to sunlight degrades the vitamin D precursor in the skin, preventing its conversion to active vitamin.

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20
Q

What are some food sources of vitamin D?

A

Fortified milk and margarine and soy beverages, eggs, butter and some fatty fish.

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21
Q

When is vitamin D supplementation recommended?

A

For breast fed infants because breast milk is a low source of vitamin D.
Infant formula is fortified with vitamin D

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22
Q

What are the functions of vitamin E?

A

Acts as an antioxidant, one of the body’s main defenders against oxidative damage
Important in red blood cells and lungs
Protect LDL from oxidation and reduce inflammation (protecting against heart disease)

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23
Q

Why is vitamin E deficiency rare?

A

It’s found in many foods.
The body stores enough to last a long time.
The cells recycle their working supply.

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24
Q

When may vitamin E deficiency occur?

A

In premature infants born before the transfer of vitamin E from mother to baby.

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25
When would vitamin E toxicity occur?
Rare. Most likely to come from supplements and fortified foods.
26
What are some food sources of vitamin E?
Vegetable oils, vegetables and fruits, fortified cereals/grains, meat and alternative and milk products. Heat processing and oxidation destroys vitamin E.
27
What does vitamin E deficiency do?
Erythrocyte hemolysis (the rupture of red blood cells) that causes hemolytic anemia (too few red blood cells)
28
What are the functions of vitamin K?
Help synthesize proteins (prothrombin, precursor for thrombin) that help clot the blood Synthesis of several bone proteins
29
Why is a dose of vitamin K given to a newborn?
Because they are born with a sterile intestinal tract and the vitamin K producing bacteria take weeks to establish. The dose is to prevent hemorrhage
30
What are some sources of vitamin K?
Intestinal bacteria | Dark, leafy green vegetables (spinach, coliard greens) and members of the cabbage family
31
What can cause a rare deficiency in vitamin K?
In conditions with fat malabsorption | Antibiotics kill the vitamin K producing bacteria
32
What are the water soluble vitamins?
C and B
33
What does vitamin B do?
Act as coenzymes and sometimes involved in energy metabolism
34
What is a source for the B vitamins?
Grain products fortified with B vitamins
35
What are the 5 active forms of vitamin B?
Thiamin, riboflavin, niacin, pantothenic acid and biotin
36
What are the functions of thiamin?
Energy metabolism of cells and nerve and muscle processes because it occupies a site on nerve cell membranes
37
What are some food sources of thiamin?
Legumes, enriched/whole grain cereals, sunflower seeds and pork
38
What is beriberi?
A thiamin deficiency disease characterized by loss of sensation in the hand and feet, muscular weakness, advancing paralysis and abnormal heart action
39
What is Wernicke-Korsakoff syndrome?
Severe thiamin deficiency seen in those who abuse alcohol due to impaired absorption
40
What are the functions of riboflavin?
Energy metabolism of all cells Supports vision and skin health Light sensitive
41
What are the food sources of riboflavin?
Milk products and enriched grain products
42
What is pellagra?
A niacin deficiency disease in which the diet has supplied inadequate niacin and tryptophan.
43
What is ariboflavinosis?
A riboflavin deficiency disease. (often undetected) | Will be deficient when thiamin is deficient and those symptoms will overshadow that of riboflavin.
44
What are the functions of niacin?
Energy metabolism of all cells. | Tryptophan (amino acid) is a precursor
45
What are the food sources of niacin?
Almost all protein (except corn protein) containing foods contain tryptophan and niacin
46
What is niacin flush?
Caused by niacin toxicity linked to supplements where the capillaries of the skin dilate, causing perceptible tingling.
47
How is niacin used as a medication?
As part of the treatment to lower blood lipids (cholesterol)
48
What are the functions of vitamin B6?
Participates in over 100 reactions in the body tissues | Metabolism of protein and amino acids
49
What are the food sources of vitamin B6?
Meats, fish and poultry
50
What happens in vitamin B6 deficiency?
Weakness, depression, confusion and irritability | May be linked to an increased incidence of heart disease.
51
Is vitamin B6 toxicity a thing?
Yes. Can cause numb feet, loss of sensations in hands and inability to walk. Recoverable
52
What is the function of folate (folic acid)?
Important role in cell division | Cells dividing rapidly are most vulnerable to deficiency.
53
Who is at risk of folate deficiency?
Pregnant women, elderly (medication interactions), alcoholics (decreased absorption) and smokers
54
What supplement should all women of childbearing age consume?
DRI committee advises 400 microgram/day of synthetic folate from supplements or enriched foods (grain products) in addition to what they get in their normal diet.
55
What is the problem with folate toxicity?
Can mask vitamin B12 deficiency by resolving the macrolytic anemia.
56
What are some food sources of folate?
1 cup Spinach 1/2 cup pinto beans, asparagus, avacado, lentils, beets 3/4 cups enriched cereal 3 oz beef liver
57
What are the functions of vitamin B12?
Required to activate folate Maintains myelin sheath of nerve fibres Coenzyme in energy and amino acid metabolism
58
What happens in vitamin B12 deficiency?
``` Neuromuscular dysfunction (creeping paralysis, etc) Idential anemia to folate deficiency Administration of folate clears anemia but allows vitamin B12 deficiency will remain undetected ```
59
What does vitamin B12 require for absorption?
An intrinsic factor (IF) which is made by the stomach. | Lack of absorption due to lack of intrinsic factor is pernicious anemia
60
What foods in vitamin B12 found in?
Found almost exclusively in foods of animal origin not in foods from plants. Many vegetarian foods are fortified with vitamin B12 (soy beverages, soy meat alternatives)
61
What should pregnant and lactating women be aware about vitamin B12 deficiency?
That it can occur in the infant even if the mother seems healthy and cannot be detected until the baby is born. Causes irreversible nervous system damage.
62
What are the functions of vitamin C (ascorbic acid)?
Many functions Maintains connective tissues (collagen) Antioxidant Recycled in body (100 mg/day only needed)
63
What happens when there is a deficiency of vitamin C?
Scurvy. The breakdown of collagen in the absence of vitamin C. Gums bleed, skin gets dry and scaly, wounds fail to heal
64
What is the UL of vitamin C?
2000 mg/day
65
What group of people need more vitamin C in their diet?
Smokers because smoking/tobacco introduces oxidants to our body that deplete the body's vitamin C. Or those who are around second hand smoke. Need an extra 35 mg/day.
66
What are some food sources of vitamin C?
Fresh, raw or quickly cooked fruits and vegetables as vitamin C is vulnerable to heat and destroyed by oxygen. 1/2 cup is one serving
67
What phytochemicals have the most solid evidence behind them?
Flavonoids and carotenoids
68
What are flavonoids?
A group of phytochemicals that may be powerful antioxidants that help protect against LDL oxidation, minimize inflammation and reduce blood platelet sickness (slowing atherosclerosis progression)
69
What are cartenoids?
The red and yellow pigments of plants. Lowers risk of hypertension and heart disease Ex: beta-carotene (vitamin A precursor)
70
What is lycopene?
A red plant pigment with powerful antioxidant activity. | Reduce risk of cancer
71
Where are phytoestrogens found and what do they do?
Reduce breast, colon and prostate cancer risk, lowers blood cholesterol Found in soy and soy products

Nutrition (9 decks)

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