Folate: Folic Acid in Health - Page 1
by A.S. Gissen -
reprinted by permission
Folic Acid (folate) -- 200
vegetable capsules by Life Extension
Folate and the Fetus
Folates have a fundamental role in cell replication through their necessity
for nucleotide synthesis and amino acid interconversions. In 1993, the
Centers for Disease Control and Prevention (CDCP) released a recommendation
that, all women of childbearing age in the United States who are capable of
becoming pregnant should consider consuming at least 400 micrograms of folic
acid per day.
Unfortunately, the entire story is more complex than it appears. Published
data are available from randomized controlled trials, non-randomized
intervention trials, and observational studies. While this is certainly
true, the supporting evidence presented by the CDCP includes numerous studies
that utilized high doses of folic acid (5 mg/day) or a lower dose (400 mcg)
together with a multivitamin. It seems a strange coincidence that these
recommendations that were made in 1993 identically match the new 1989 US RDA
recommendation of 400 mcg/day. Prior to 1989 the US RDA recommendation was
800 mcg/day, which is more in line with the higher doses of folic acid.
They also recommend this high dose of folic acid be taken under a physicians
Sadly, the entire debate over how much folate is necessary has missed an
important point: that, research in humans and other animals has shown
other nutrient deficiencies. One of these other nutrient deficiencies
involves vitamin B12. Folate and
vitamin B12 affect similar biosynthetic pathways in the body, and supplements of
folic acid can overcome some clinical symptoms of vitamin B12 deficiency.
It is entirely possible that some or all of the positive effects of folic acid
supplementation may simply be due to partially overcoming a subclinical vitamin
B12 deficiency. Hopefully, we won't have to wait another 30 years for the
potential of vitamin B12 to be recognized.
Supplement Facts: Serving Size - 1 Capsule. Servings/Container - 200
|Folic Acid (as L-5-methyltetrahydrofolate calcium salt)
|Vitamin B12 (as methylcobalamin)
Microcrystalline cellulose, vegetable cellulose (capsule), dicalcium phosphate.
1931, the treatment for a major health problem consisted of the yeast
extract called marmite. It contains an active ingredient
subsequently isolated from spinach ten years later. This active
component is today known as folate, a member of the vitamin B
complex. A deficiency of folate results in the development of a
condition which is morphologically indistinguishable from that
associated with a deficiency of vitamin B-12. Research in the last
few decades has firmly established folic acid's role in many
physiological functions essential for health.
Chemistry and Functions
Folate is a generic term that refers to different forms of pteroyl (poly) -
glutamate(s) conjugates. In 1945 folic acid was synthesized, and this
synthetic material was found to have therapeutic activity similar to the natural
vitamin. Pteroylglutamic acid, today known as folic acid, is a naturally
occurring pteridine derivative comprising three basic parts -- a pteridine,
para-aminobenzoic acid, and glutamic acid. Folic acid is a monoglutamate,
containing one glutamic acid residue. This form does not occur in nature
where folates are always present as polyglutamates with up to eleven glutamic
acid residues. In most mammals, including humans, the transport form of
the vitamin is a monoglutamate, and this is the form found in blood plasma and
extracellular fluids. The active coenzyme forms of the vitamin, however,
are polyglutamates with between four and six glutamic acid residues.
Folic acid is an essential dietary component and has a role in a number of
reactions involved in amino acid and nucleotide metabolism. Different
coenzyme forms exist as a result of variations in the reduction state of the
pteridine ring, the C1 group attached to pteroic acid, and the number of
glutamic acid residues.
Folate Intake and Absorption
Humans are totally dependent on food as a source of folate. Although
there are folate producing bacteria in the human digestive tract, they
contribute little to folate status. Despite over fifty years of research,
the actual folate requirement for optimum health is undecided. The World
Health Organization (WHO) has suggested that adults require 400 micrograms per
day, and pregnant women should receive at least 800 micrograms per day.
This twenty-five year old recommendation coincided with the United States
Recommended Daily Allowance (RDA) until 1989, when the RDA was lowered to 200
micrograms per day for adults and 400 micrograms per day for pregnant
women. Using data from a large population survey of dietary intake, it was
found that in the United States folate intake ranges from 8 micrograms to 5
milligrams per day. The mean folate intake was 242 micrograms per day, and
half of all individuals were consuming less than 200 micrograms of folate daily.
Because food folates are present as polyglutamates of varying chain lengths in
food, whereas folates that circulate in the plasma exist in the form of
monoglutamates, deconjugation to monoglutamates is required before
absorption. Thus, in the process of assimilation, folates in the diet as
polyglutamates must be hydrolyzed to the monoglutamate form. The
hydrolysis, or digestion, of folates into their utilizable monoglutamate form
occurs predominantly in the small intestine. Because digestion of folates
to folic acid is required for utilization, the bioavailability of folates in
food varies. It is low for some foods that contain nutritionally important
amounts of folate, such as legumes, orange juice, and tomatoes. Extracts
of these foods significantly inhibit activity of the intestinal enzyme that
converts dietary polyglutamyl folates into the monoglutamyl form prior to
absorption. A review of studies on folate bioavailability from numerous
food sources showed that estimates of folate bioavailability varied
widely. Folic acid in dietary supplements, as opposed to the folates found
in food, requires no digestion prior to absorption and demonstrates excellent
(folate) Supplements - Page 2
Cut Cancer Risk With Folate, Study Finds
(folate) Supplements |
B12 methylcobalamin | Vitamin K1, K2 |
Vitamin C |
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