Checking folate levels

New methods to analyse the essential B vitamin folate, both in foods and in blood products, are being developed by scientists to help in setting recommended folate levels.

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 'family' of folates includes folic acid, which is the major synthetic form of folate used by food processors to fortify foods. Evidence shows that the risk of birth defects drop if mothers-to-be consume sufficient folic acid.

Microbiological and protein-binding assays have commonly been used to analyse the total folate in foods. But those methods do not measure the individual folates separately, according to the US Agricultural Research Service researcher James Harnly at the Food Composition Laboratory in Beltsville, Maryland.

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-labelled 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 analyse folate. The 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.

More information on the research can be found from the ARS​.