B 12 , folate helps regulate the level of the amino acid
homocysteine in the blood. Homocysteine regulation
is related to cardiovascular health. In the fetus, folate
is necessary for the proper development of the brain
and spinal cord.Description
Folate is one of eight B-complex vitamins. Its
function is closely intertwined with that of vitamins
B 6 and B 12. Folate, from the Latin wordfoliummean-
ing leaf, was discovered in the late 1930s in yeast and
later found in spinach and other green leafy vegetables
and in liver. Starting in 1998, the United States Food
and Drug Administration (FDA) required certain
foods, such as flour, corn meal, bread, cereal, rice,
and pasta, to be fortified with a folic acid. In Canada
and Chile fortification of flour is mandatory.Folate’s role in health
Folate is essential for the normal development of
the neural tube in the fetus. The neural tube develops
into the brain and spinal cord. It closes between thethird and fourth week after conception. Too little
folate at this time can lead to serious malformations
of the spine (spina bifida) and the brain (anencephaly).
Because many women do not realize that they are
pregnant so soon after conception, the United States
has included folic acid in its fortified foods program.
Adding folic acid to common foods made with grains
has substantially reduced the number of babies born
with neural tube defects in the United States.
The body also needs folate to produce healthy red
blood cells. When not enough folate is present, the red
blood cells do not divide; instead they grow abnor-
mally large. These malformed cells have a reduced
ability to carry oxygen to other cells in the body.
This condition is called megaloblastic anemia. It is
identical to the condition of the same name caused
by too little vitamin B 12. Folate also aids in the pro-
duction of other new cells. Adequate supplies of folate
are especially important in fetuses and infants because
they are growing rapidly. However, since the lifespan
of a red blood is only about four months, the body
needs a continuous supply of folate throughout life to
create healthy new replacement blood cells.
Folate acts together with vitamin B 6 and vitamin
B 12 to lower the level of homocysteine in the blood.
Homocysteine is an amino acid that is naturally pro-
duced when the body breaks downprotein. Moderate
to high levels of homocysteine in the blood are linked
to an increased risk of cardiovascular disease (e.g.
atherosclerosis, heart attack, stroke). The trio of
folate, vitamin B 6 , and vitamin B 12 lower homocys-
teine levels. However, it is not clear whether taking
large doses of these vitamins, either alone or in combi-
nation, will prevent heart disease from developing in
healthy individuals. The official position of the Amer-
ican Heart Association stated in its Diet and Lifestyle
Recommendations Revision 2006 is that ‘‘Available
evidence is inadequate to recommend folic acid and
other B vitamin supplements as a means to reduce
CVD [cardiovascular disease] risk at this time.’’
Damage to DNA appears to contribute to the
development of many different cancers. Because folate
helps protect against DNA damage, researchers have
looked at whether it can reduce the risk of developing
cancer. Results are mixed, with benefits seen for some
cancers, but not for others. The American Cancer
Society in its 2006 Guidelines on Nutrition and Phys-
ical Activity for Cancer Prevention states: ‘‘Folate
deficiency may increase the risk of cancers of the color-
ectal and breast, especially in people who consume
alcoholic beverages. Current evidence suggests that
to reduce cancer risk, folate is best obtained through
consumption of vegetables, fruits, and enriched grainFolate (Folic Acid)Recommended Tolerable Upper
Dietary Allowance Intake Level
Age (mcg) (mcg)
Children 0–6 mos. 65 (AI) Not established
Children 7–12 mos. 89 Not established
Children 1–3 yrs. 150 300
Children 4–8 yrs. 200 400
Children 9–13 yrs. 300 600
Children 14–18 yrs. 400 800
Adults 19 yrs. 400 1,000
Pregnant women 600 1,000
Breastfeeding women 500 1,000
Folate (Folic Acid)
Food (mcg)
Cereal, 100% fortified, ¾ cup 400
Beans, pinto, cooked, ½ cup 147
Turnip greens, cooked, ½ cup 135
Asparagus, cooked, ½ cup 132
Spinach, cooked, ½ cup 131
Beans, navy, cooked, ½ cup 127
Beans, great northern, cooked, ½ cup 90
Broccoli, steamed, ½ cup 85
Beets, boiled, ½ cup 68
Rice, long-grain white, enriched, cooked, ½ cup 65
Corn, yellow, cooked, ½ cup 37
Tomato juice, canned, 6 oz. 35
Bread, white, enriched, 1 slice 25
Bread, whole wheat, enriched, 1 slice 25
Raspberries, ½ cup 16
AI Adequate Intake
mcg microgram(Illustration by GGS Information Services/Thomson Gale.)Folate