Vitamins

Question 1

How does RDI and EAR differ for vitamins?

Answer 1

RDI- safety net value which is based on population distribution

EAR- more realistic values and are based on individuals

Question 2

What are some general features of water soluble vitamins?

Answer 2

less complex

not stored- excreted in urine

Question 3

What are some general features of fat soluble vitamins?

Answer 3

more complex
absorbed in ileum
stored and released when fat is broken down

Question 4

What factors affect bioavailability of vitamins?

Answer 4

efficiency of digestion
other foods consumed simultaneously
natural vs synthetic
food preparation (esp. water soluble)

Question 5

What are the water soluble vitamins?

Answer 5

Vitamin C
B vitamins:
Thiamine; Riboflavin; Niacin; Pyridoxine; Biotin; Folate; B12 (cobalamin)

Question 6

Thiamine: active form, function, primary deficiencies and source.

Answer 6

Active form: TPP (thiamine pyrophosphate)
Function: coenzyme of carb metabolism
1 Deficiencys: Wet Beri beri- thiamine deficiency that causes edema and cardiac failure; Dry Beri beri- PEM causes muscle wasting of extremities and peripheral neuropathy
2 deficiencies: alcoholism can cause deficiency; wernicke encephalopathy- alcohol related brain damage where there is language problems and walking is a struggle; korsakoff syndrome- amnesia and inability to learn
Source: whole grain cereals and legumes

Question 7

What is riboflavins major function?

Answer 7

coenzyme of carb. metabolism

Question 8

Folate: active form, function. deficiency diseases, causes, source?

Answer 8

Active form: tetrahydrofolate
Function: Methylation in DNA synthesis (B12 is coenzyme)
DD: Macrocytic anaemia, NTDs and potential incrrease in cancer
Causes: pregnancy, reduced absrption/intake
Source: leafy green vegetables, legumes and liver

Question 9

What are the fat soluble vitamins?

Answer 9

Vitamins A, D, E and K

Question 10

Vitamin A: forms, role in vision, protein synthesis, DD and toxicity

Answer 10

Forms: Vit. A animal based; B carotene plant based; retinol stored in fat; retinal for vision; retinoic acid for growth
Vision: retina cells contoin rhodopsin (contain retinal) need trans version.
PS: moitens cell membrane
DD: night blindness; keratinisation; moisten cornea
toxicity: B carotene overconsumption lead to orange skin; retinol overconsumption from supplements

Question 11

Vitamin D: names; function; DD; sources

Answer 11

Names: calciferol, D3 (plants) D2 animals,
Function: increases calcium absorption, maintains bone health
DD: rickets and osteomalacia
Source: (need sunlight), liver and fatty fish (cod liver oil)

Question 12

Who needs vitamin and mineral supplements?

Answer 12

• poor nutrient intake (elderly, diabetes, vegetarians)
• increased nutrient requirements (preganncy, children, lactation)
• increased metabolic demands (trauma, surgery)
• maldigestion or malabsoprtion