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How Low Does Your Folate Go?
By Rosalie Marion Bliss
January 3, 2003
Agricultural Research 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 rates.
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 James 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 investigations.
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.
Read more about folate analysis by ARS in Agricultural Research magazine.
ARS is the chief scientific research agency of the U.S. Department of Agriculture.