1.5.4.g. Vitamin B9 (Folate)

Pteroylglutamic acid (PGA)

What is the chemical name of folic acid?

Tetrahydrofolate (THF; tetrahydrofolic acid)

What is the principal active coenzyme form of folate?

It comes from the Latin folium, meaning leaf, reflecting its original isolation from leafy material.

What does the name folic refer to?

Free folate and conjugated folate

What are the two forms of folate naturally present in food?

Conjugase

What enzyme converts conjugated food folate into an absorbable free form?

Polyglutamate (conjugated) form

Most naturally occurring food folate exists in what form?

About 25%

About what percentage of food folate occurs as the readily digested free form?

Synthetic folic acid

What form of folate is commonly used for supplementation and food fortification?

Milligrams (mg) or micrograms (µg)

In what units is folic acid measured?

Transfer of one-carbon (C₁) units

What is the major biochemical role of folate?

Donors and acceptors of one-carbon units

Folate coenzymes act as what during one-carbon metabolism?

Amino acid and nucleotide metabolism

What major cellular processes require folate-mediated one-carbon transfer?

Thymine and purines

Which DNA-related compounds require folate for synthesis?

It is required for DNA synthesis through purine and thymine formation.

Why is folate essential for rapidly dividing cells?

Methionine and choline

Folate participates in methyl-group transfer involving which compounds?

Erythropoiesis

What blood-forming process requires folate together with vitamins B₁₂ and C?

Neural tube defects, such as spina bifida

What important congenital defect is prevented by adequate folic acid intake around conception?

400 µg/day

How much folic acid does the text recommend daily for women capable of becoming pregnant?

Small intestine

Where is folic acid primarily absorbed?

Yes

Can intestinal bacteria synthesize folate?

Relatively unstable; sensitive to heat and light

How stable is folate during food preparation?

Boiling and frying

Which cooking methods can cause substantial folate destruction?

As a protein conjugate

How is folate transported in the body according to the text?

Liver

Where is a small reserve of folate stored?

Mainly through the urine, with some through the feces

How is excess folate excreted?

Aminopterin, tetrahydroaminopterin, and pteroyl-aspartic acid

Which compounds are identified as folic acid antagonists in the text?

Megaloblastic macrocytic anemia

What type of anemia is classically associated with folate deficiency?

Megaloblasts

What abnormal precursor cells are characteristic of folate-deficiency anemia?

Glossitis and stomatitis

What oral manifestations may occur with folate deficiency?

Gastrointestinal disturbances

What gastrointestinal manifestation may occur with folate deficiency?

Sprue and other gastrointestinal disorders

Which conditions can predispose a person to folate deficiency according to the text?

Alcoholism

What lifestyle factor increases folate requirements?

Growth, pregnancy, and lactation

Which periods increase folate requirements?

Folate can improve the megaloblastic blood picture, but it does not correct the neurologic effects of vitamin B₁₂ deficiency.

Why can folic acid improve the anemia of vitamin B₁₂ deficiency without fully treating the disease?

Vitamin B₁₂ deficiency

Which deficiency should be ruled out before treating unexplained megaloblastic anemia with folic acid alone?

Megaloblastic macrocytic anemia

Folate deficiency and vitamin B₁₂ deficiency can both cause what type of anemia?

Neurologic manifestations are characteristic of vitamin B₁₂ deficiency

What major feature distinguishes vitamin B₁₂ deficiency from isolated folate deficiency?

400 µg DFE/day

What Philippine RNI for folate is listed for older children, adolescents, and adults?

600 µg DFE/day

What is the folate requirement listed for pregnancy?

500 µg DFE/day

What is the folate requirement listed for lactation?

Dietary Folate Equivalent

What does DFE mean in folate recommendations?

Green leafy vegetables, liver and other glandular organs, legumes, and cereals

What are the best general food sources of folate?

Milk, eggs, poultry, and fruits

Which foods are considered relatively poor folate sources according to the text?

Chicken liver

Which organ food listed has a particularly high folate content?

Lentils, soybeans, and green peas

Which legumes listed are rich sources of folate?

Spinach/dark green leaves and broccoli

Which vegetables listed are particularly good folate sources?

Orange juice

Which fruit or fruit product listed contains a relatively high amount of folate?

THF — tetrahydrofolate

Folate → active coenzyme?

One-carbon transfer

Folate → principal biochemical job?

Purines + thymine

Folate → DNA synthesis?

Erythropoiesis

Folate → blood formation?

Megaloblastic macrocytic anemia

Folate deficiency → classic anemia?

Megaloblasts

Folate deficiency → characteristic abnormal cells?

Prevention of neural tube defects

Folate during pregnancy → major preventive role?

600 µg DFE/day

Folate + pregnancy RNI?

Folate may correct the anemia while neurologic damage from B₁₂ deficiency persists

Folate + vitamin B₁₂ deficiency warning?