Folate (B9)

Question 1

What is the difference between folate and folic acid?

Answer 1

Folate is the general term for food sources of vitamin B9 and folic acid is the supplement form

Question 2

Which form of vitamin B9 is most potent?

Answer 2

Synthetic form (folic acid) is more potent than natural form (folate)

Question 3

Why is folic acid more bioavailable than folate?

Answer 3

Folic acid is a monoglutamate (100% bioavailable)

Folate is a poly glutamate which needs to be broken down

Monoglutamate is the absorption form

Question 4

How is folate absorbed?

Answer 4

In the monoglutamate form (folic acid form) so polyglutamates must be broken down by folate conjugase

Folic acid passively diffuses into enterocytes

Question 5

Which enzyme converts poly glutamates to monoglutamates?

Answer 5

Folate conjugase

Question 6

What is the coenzyme form of folate?

Answer 6

Tetrahydrofolic Acid (THFA)

Conversion occurs in enterocyte and liver

Question 7

In what form does folate circulate in the body?

Answer 7

5-methyl-THFA

Question 8

In what form is folate stored in the body?

Answer 8

Converted back to polyglutamate form in the cells, which traps it inside

Question 9

Where is folate stored?

Answer 9

Liver

enough to last for months

Question 10

What are the functions of folate?

Answer 10

• cell division and proliferation
• DNA synthesis and repair: THFA donates methyl group to uracil to become thyamine (very important in pregnancy)
• Conversion of homocystein to methionine with B12
• Formation of dopamine, serotonin and adrenaline

Question 11

What occurs in folate deficiency?

Answer 11

• Impaired DNA synthesis and repair (especially in rapidly dividing cells such as GIT and RBCs)
• Megaloblastic Macrocytic Anemia: large and immature RBCs (not as much oxygen carrying capacity)
• Peri-conception: neural tube defects (spina bifida)

Question 12

What are the dietary folate equivalents?

Answer 12

1μg of dietary folate equivalents
= 1μg of food folate
= 0.5μg folic acid (empty stomach)
= 0.6μg folic acid with food

Question 13

What are good food sources of folate?

Answer 13

• lentils
• black beans
• avocado

Question 14

What can cause folate deficiency?

Answer 14

• anti-cancer recurrence meds
• polymorphism of folate conjugase so decreased polyglutamates converted to mono
• alcoholism
• B12 deficiency

Question 15

What occurs in folate deficiency?

Answer 15

Can mask B12 deficiency as they have the same symptoms, but B12 has irreversible consequences

Increased carcinogens due to DNA damage

Adverse reproductive and developmental effects