Vitamin Lecture 1 Flashcards

1
Q

What was believed to be the four required nutritional components in the late 19th century

A

Fats, proteins, carbohydrates, and minerals

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2
Q

what were the previous observations that challenged the belief that there were only four nutritional components

A

Number of diseases not caused by infections or deficiencies in one of the four groups

During the siege of paris in 1870, many infants and toddlers died when the city was cut off from outside milk, and synthetic milk did not work

When young mice were fed milk-bread they grew but when the dough was extracted to removed non-polar molecules the mice died

Young rats fed the four groups did not grow well, when milk was added, they grew

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3
Q

Who is the father of the vitamin

A

Casimir Funk: he isolated vitamins B1 and B3, and developed formulas for vitamin A and D

Proposed the name vitamine based on their life-supporting role

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4
Q

What were the limitations of Casimir Funk’s research

A

Thought all vitamins were amines
Proposed that a vitamin worked with a single mode of action

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5
Q

Why did beriberi skyrocket

A

Disease
Rice was stripped off the outer layer in the mid 1800s
and then beriberi skyrocketed until someone found that the outer layer contained vitamin B1

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6
Q

What are vitamins? Functions? required characteristic?

A

Structurally diverse group

13 organic small molecules that play essential role in cellular metabolism and health maintenance

Most common function is coenzymes/cofactors, but also include regulators of transcription and antioxidant roles

required characteristic is that is required in the diet and cannot be made in the body in sufficient quantities

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7
Q

How are vitamins classified

A

Characterized based on the chemical property of solubility in either water or fat

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8
Q

What are the water soluble and fat soluble vitamins

A

Water-soluble: B1, B2, B3, B5, B6, B7, B9, B12, C

Fat-soluble: A, D, E, K

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9
Q

Alternate name for vitamin B7 (biotin)

A

Vitamin H

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10
Q

What happened to vitamin B4, B8, B10, B11

A

Did not fit the definition of a vitamin

Can make all of them

B10 made by bacteria in our gut

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11
Q

T/F vitamins are structurally diverse

A

True

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12
Q

What are the most common sources of vitamins

A

Fruits and vegetables except for B12

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13
Q

Vegetarians often get what deficiency?

A

B12 deficiency

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14
Q

Which diseases are caused by deficiencies: A, B1, B2, B3, B5, B6, B7, B9, B12, C, D, E, K

A
  • A – night blindness; hyperkeratosis
  • B1 – Beriberi (peripheral nerve damage)
  • B2 – lesions at corner of mouth, lips, tongue;
    dermatitis
  • B3 – Pellagra (depressive psychosis; dermatitis)
  • B5 - “burning foot syndrome” (peripheral nerve damage)
  • B6 – disorders of amino acid metabolism; convulsions
  • B7 - dermatitis
  • B9 – Neural tube defects, megaloblastic anemia
  • B12 – megaloblastic anemia with degeneration of spinal cord
  • C – scurvy
  • D – rickets (poor mineralization), osteomalacia (demineralization)
  • E – deficiency very rare; neurological dysfunction
  • K – impaired blood clotting
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15
Q

What is the biological availability of vitamins determined by

A

The extent of digestion, absorption of the digested material, and the metabolism of the nutrient which are all subject to specific factors

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16
Q

6 specific factors of biological availability

A
  1. Many vitamins are absorbed by active transport, which is saturable. Thus, a lower percentage is absorbed as the concentration gets higher.
  2. The absorption of fat soluble vitamins is affected by the lipid content of the food eaten.
  3. A number of water soluble vitamins are bound to protein, and require to be released by acidic conditions in the stomach or by specific hydrolases
  4. The total body reserves of a vitamin can affect absorption rate e.g. by affecting the synthesis of proteins that bind and transport vitamins, or by altering metabolism of vitamin
  5. Foods can have antivitamin compounds e.g. thiaminases
  6. Drugs/medications and compounds present in food can compete for absorption e.g. some
    antidepressants block riboflavin availability; natural carotenoids can compete for b-carotene for absorption
17
Q

What does a biochemical assessment of vitamin status include

A

Determination of levels in plasma and urine, in rare cases in tissues

18
Q

Four major methods used to determine vitamin requirements

A

Population studies of intake
depletion/repletion studies
replacement of metabolic loss
Examination of patients on total parenteral nutrition

19
Q

Which type of vitamins tend to show more toxicity

A

Fat-soluble vitamins
Water soluble toxicities are very rare

20
Q

Toxicities of vitamins A, D, E, K, C, B (B3 and B6)

A

A: RDA is 900ug/day and upper limit is 300ug
D: RDA is 20 ug/day and UL is 100ug
K: RDA is 125ug/day and no UL, toxicity is very rare
C: RDA 75-90mg/day and UL is 2000mg
B3: RDA is 16mg/day and UL is 2000mg
B6: RDA is 1.3mg/day and UL is 1000mg/day

21
Q

Why do people continue taking vitamin supplementation even though evidence is lacking

A

Most people want to believe that it will improve or maintain their health

Growing distrust in science

22
Q

T/F multivitamins failed to prevent cancer, heart disease, and all causes of death for all women they tracked – REGARDLESS OF HEALTHY EATING HABITS

A

true

23
Q

Do multivitamin supplementation work

A

No, except for in developing countries where there are lots of deficiencies

24
Q

what does vitamin C supplementation do

A

Helps prevent scurvy

does not prevent cancer or any chronic disease

Slightly reduce duration of a cold

25
Q

What does vitamin E supplementation do

A

Vitamin E slightly increased the risk of hemorrhagic strokes
Did not prolong life or protect against disease
slightly higher risk of lung cancer
Higher risk of prostate cancer
No evidence for alzheimer’s disease

26
Q

What are food fortifications

A

There is a list of foods that may or must be fortified with vitamins

27
Q

4 things

Policy highlights for food fortifications

A

Must fortify foods that have lost nutritional quality
Fortify foods with vitamins to prevent nutrional problems
Fortify foods to help canadians meet RDIs
Fortification cannot be permitted when no rationale can be provided

27
Q

Why is fortification not permitted when there is no nutritional rationale

A

Didn’t want to trivialize the importance of vitamins and it prevents overfortification

27
Q

Why is vitamin deficiency rare

A

Because of food fortification