IZiNCG Technical Brief no. 11 is now available! The brief describes a low-tech, low-cost Polyacrylamide Gel Electrophoresis method for measuring phytic acid.
Dietary phytic acid reduces zinc absorption and is an important cause of zinc deficiency, especially for populations in low-income countries where diets rely on unrefined cereals and legumes. In order to estimate the risk of zinc deficiency or to establish dietary zinc recommendations in a population, measuring the phytate content of food is required
Phytic acid, myo-inositol hexaphosphate (IP6)
In addition to phytic acid, or myo-inositol hexaphosphate (IP6), its breakdown product IP5 can also negatively impact zinc absorption. However other, less-phosphorylated inositol phosphates (IP4 onwards) have a much lower effect. Therefore, analytical methods must have the ability to separate out phytic acid and its breakdown products.
The current gold standard for analysis of phytic acid and its breakdown products is analysis by high-performance liquid chromatography (HPLC). This method requires specialized, expensive equipment and highly trained technicians.
Polyacrylamide Gel Electrophoresis (PAGE) methods are common in many laboratories. A PAGE method has been developed that has an adequate detection level for typical levels of phytic acid in foods, provides adequate separation and quantification of phytic acid and less-phosphorylated inositol phosphates, is high-throughput, low-cost (10% of HPLC), widely available, and does not require substantial expertise or training.
This new Technical Brief provides an overview of the PAGE method in comparison to HPLC. It is also accompanied by a Practical Tips document describing the method in more detail, targeted at laboratory technicians.
Other Technical Briefs on on dietary assessment and phytic acid from IZiNCG:
Technical Brief no. 5 Preventing zinc deficiency through diet diversification and modification
Technical Brief no. 7 Tools to assess dietary zinc intake in populations
