Water Soluble Vitamins (Vitamin C, Niacin, Vitamin B6, Vitamin B12, and Folic Acid)

Question 1

Bioavailability

Answer 1

extent to which a nutrient can be absorbed and utlized by the body

Affected by: genetics, nutritional status, growth and development, other nutrients, the dose of micronutrient, form of nutrient (food vs. supplement)

Question 2

Functions of Vitamin C

Answer 2

• antioxidant
• helps with regeneration of Vitamin E
• Carnitine synthesis
• Tyrosine synthesis
• Serotonin synthesis

Question 3

Population that requires higher amounts of Vitamin C than the RDA

Answer 3

smokers

Question 4

Role of Vitamin C in immunity (according to Cochrane review of clinical trials)

Answer 4

helps you get over a cold more quickly (reduces cold durations)

Question 5

Why does an all corn diet results in niacin deficiency?

Answer 5

Corn has two sources of niacin, but neither are bio available

• free niacin is bound by proteins and can’t be accessed
• has small amounts of tryptophan which synthesizes niacin (not bioavailable because Leucine uses the same carrier protein)

Question 6

Functions of Vitamin B6

Answer 6

• involved in transamination reactions

- cofactor in heme synthesis and lipid synthesis

Question 7

Active forms of Vitamin B12

Answer 7

Adenosylcobalamin

Methylcobalamin

Question 8

Best sources of Vitamin B12

Answer 8

Meat, dairy, sea food, and eggs

Question 9

Which special population might need Vitamin B12 and why?

Answer 9

• Vegans and elderly people

- Found ONLY in animal products (so vegans wouldn’t get any)

Question 10

How is Vitamin B12 absorbed?

Answer 10

• R-proteins bind to B12 in the stomach to prevent bacteria from using it
• R is dissolved and B12 binds to intrinsic factors (in the small intestine)
• The receptors take up B12 bond to intrinsic factor

Question 11

How is Vitamin B12 transported?

Answer 11

B12 is transported bound to transporters called Transcobalamin I, II, and III (TCBI, TCBII, TCBIII)

Question 12

Functions of Vitamin B12

Answer 12

• helps in DNA methylation (acts as methyl donor in production of DNA)
• helps make red blood cells

Question 13

Results of Vitamin B12 deficiency

Answer 13

• Neuropathy (nerve problems)

- Pain in extremeties

Question 14

Functions of Folic Acid

Answer 14

• methyl donor with Vit B12 (DNA synthesis)

Question 15

Results of Folic Acid deficiency

Answer 15

• nerve damage (forgetfulness, irritability, hostility)
• Buildup of homocysteine (neurotoxin and potential heart disease risk)
• inadequate nucleotide (in DNA synthesis)
• Cancers