Folate

Question 1

Folate

Answer 1

• Needs to be digested into folic acid
• reduced form of folic acid
• food form
• fortified in all commerical food items in 1998

Question 2

Factors affecting folate digestion

Answer 2

• zinc deficiency
• chronic alcohol ingestion
• conjugase inhibitors ( decrease digestion)
• —LEntils and cabbage
• heart and pH sensitive

Question 3

Folate absorption

Answer 3

• inside intenstional cell
• folic acid reduced to THF
• -Dihydrofolate reductase
• • 4 additional H ions added at 5-8
• —5-methyl THF
• -Tetrahydrofolate

Question 4

Folate food sources

Answer 4

green leafy vegetables, orange juice, strawberries, legumes and fortified foods since 1998

Question 5

Bioavailability of folate

Answer 5

food folate = 50 %

folic acid = 85% (1.7x) used as fortificant

Question 6

Functions of folate

Answer 6

1) conversion of HCY to methionine

2) important for DNA synthesis and making new cells

Question 7

Disease Risk associated with Folate

Answer 7

1) neural tube defects
2) CVD
3) megoblastic anemia

Question 8

Neural tube Defect

Answer 8

fails within first 23 days
effects 1/1000 births
intake of more than 400mg/day decrease risk by 75%
1) anencephaly -absence of cerebral hemisphere
2) spine bifida -defective closure of vertebral column

Question 9

CVD

Answer 9

defect in breaking down cystine (accumulates in blood to cause heart prob.)
HCY increase =20% increase in risk
mechanism-
-increase LDL oxidation
-increase thrombosis (increase blood clots)
- toxic effect on endothelial cells

Question 10

Megoblastic anemia

Answer 10

detected by kidneys
decreased DNA synthesis
cells in marrow fail to divide
large, immature cells

also occurs in b12 deficiency

Question 11

Relationship with v B12

Answer 11

• Methyl trap hypothesis
• -THF is not regenerated
• -Thymidine synthesis decreased
• -RBC decreased their ability to carry O2

Question 12

Folate RDA

Answer 12

• 400 mcg/d for adults of child bearing age
• 1 DFE= 1 mcg food folate
  0. 6 mcg fortified w/food
  0. 5 mcg supplement on empty stomach

Question 13

Folate enrichment

Answer 13

-140 mcg folic acid/100g of flour
-200 mcg acid per day for average diet
NTD dropped by 25%

Question 14

Population at risk

Answer 14

elderly 
alcoholics
achlorhydria
IBD
pregnant/lactating 
medications = phenytoin, cholestryamty

Question 15

Folate Toxicity

Answer 15

UL= 1,000 mcg/d
V-b12 mask- deficiency mask
-feeds cancers
-delays diagnosis of b12 deficiency by correcting anemia

Question 16

Assessment

Answer 16

FIGLU excretion
histidine load test =5-10 mg=norm
–not a good test because of variation