How Low Does Your Folate Go?
By Rosalie Marion
January 3, 2003
Service scientists at the Food Composition Laboratory in
Beltsville, Md., have been developing new methods to analyze the essential B
vitamin, folate, both in foods and in blood products. Folate is important to
blood-cell makeup and for regulation of the amino acid homocysteine. Folate is
also involved in helping the body form genetic material, or DNA.
The generic term "folate" is used for a family of related
compounds that exhibit similar vitamin activity within the body. The family
includes folic acid, which is the major synthetic form of folate used by food
processors to fortify foods. Each folate is absorbed by the body at different
Microbiological and protein-binding assays have commonly been
used to analyze the total folate in foods. But those methods do not measure the
individual folates separately, according to research leader
Harnly at the Beltsville laboratory..
Newer instrumental methods for determining folates use
high-performance liquid chromatography, or HPLC. One new ARS method combines
the separating power of HPLC and the molecular identification capabilities of
mass spectrometry, or HPLC-MS. This combination, with the addition of stable
isotope-labeled folates containing five carbon-13 atoms to food samples, allows
scientists to detect and measure very low levels of specific folates. Though
expensive, this method is especially effective because the accuracy of the
analysis is not affected by normal folate loss during processing.
The ARS lab is now perfecting a less expensive, yet sensitive
and selective, method to analyze folate. This method is HPLC with fluorescence
detection, which uses light emission to measure folates--a method similar to
that of looking for blood with "black light," as used in some crime
Accuracy in measuring folate is important to experts who
establish and reexamine the nationally recommended folate levels and who
monitor the folate fortification program. Evidence showed that risks of birth
defects would drop if mothers-to-be consumed more folic acid.
about folate analysis by ARS in Agricultural Research magazine.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.