Dietary folate equivalents

Introduction

Dietary folate equivalents (DFEs) are a unit of measurement used to account for the different bioavailabilities of folate from different sources. Folate is a B vitamin found naturally in some foods and added to others. It is also available as a dietary supplement.

Naturally occurring folate in food is in the tetrahydrofolate (THF) form, which is readily absorbed by the body. However, folate can be lost during food processing and storage.

Folic acid is the synthetic form of folate used in fortified foods and most dietary supplements. Folic acid needs to be converted to THF before it can be used by the body, and this conversion is not always complete.

https://www.fda.gov/food/nutrition-facts-label/folate-and-folic-acid-nutrition-and-supplement-facts-labels

To account for these differences in bioavailability, the following conversion factors are used:

• 1 mcg DFE = 1 mcg of food folate
• 1 mcg DFE = 1.7 mcg of folic acid from fortified foods or dietary supplements consumed with food
• 1 mcg DFE = 2 mcg of folic acid from dietary supplements taken on an empty stomach

The recommended dietary allowance (RDA) for folate is 400 mcg DFE per day for most adults. However, some groups of people, such as pregnant women and women who are breastfeeding, have higher folate needs.

Here are some good sources of dietary folate equivalents:

Leafy green vegetables: Spinach, kale, collard greens, romaine lettuce

Beans and lentils: Black beans, kidney beans, chickpeas, lentils

Citrus fruits: Oranges, grapefruits, tangerines

Fortified cereals and breads: Look for cereals and breads that are enriched with folic acid

Liver: Beef liver is a particularly good source of folate

Importance of testing

Testing for Dietary Folate Equivalent (DFE) in foods is important for several reasons, especially in the context of nutritional labelling and public health. Here are some key reasons:

Regulations and Standards of Folate in Foods: FSSAI, EU, and USFDA

Mandatory and optional analyses for folate in foods

Mandatory analyses:

• Folate content: This is the essential analysis for all fortified foods and mandatory by regulations in several countries like India and the US. This analysis measures the total folate content, often reported as micrograms (mcg) of dietary folate equivalents (DFEs) per gram or per serving.
• Moisture content: This analysis is crucial for calculating the accurate folate concentration per dry weight basis, as water content can vary between different food samples.
• Particle size and distribution: This analysis is relevant for fortified foods like flour or powdered supplements to ensure even distribution of folic acid and consistent bioavailability.

Optional analyses:

Folate form differentiation: This analysis distinguishes between naturally occurring folate forms (e.g., tetrahydrofolate) and added folic acid. It can be helpful for research purposes or understanding specific absorption characteristics.

Stability testing: This analysis assesses how well the folate content remains intact over time under different storage and processing conditions. This is important for manufacturers and shelf-life determination.

Bioavailability studies: These studies directly measure the body's ability to absorb and utilize folate from the food. While not routinely required, they provide valuable information for understanding nutritional impact.

Contamination analysis: This analysis checks for potential contaminants like heavy metals or pesticides that might affect folate quality or safety. While not usually mandatory, it might be required for specific regulations or quality control measures.

Additional Considerations:

Analytical methods used for these analyses depend on the specific purpose and resources available. Common methods include microbiological assays, high-performance liquid chromatography (HPLC), and enzyme-linked immunosorbent assays (ELISA).

The specific mandatory and optional analyses might vary depending on the country, regulatory requirements, and type of food product.

Eurofins role in testing folate in foods

Eurofins, a leading provider of food and feed testing services, plays a significant role in analyzing dietary folate equivalent (DFE) in various food products. Here are some key aspects of their involvement:

Analytical Services:

• Eurofins laboratories possess state-of-the-art equipment and utilize advanced techniques like HPLC (High-Performance Liquid Chromatography) and LC-MS (Liquid Chromatography-Mass Spectrometry) to accurately measure DFE levels in food samples.
• They offer comprehensive testing services that encompass both naturally occurring folates and added folic acid, accounting for potential conversions and bioavailability differences.

Quality Control and Assurance:

• Eurofins helps food manufacturers maintain consistency in their products by testing DFE levels in raw materials and finished goods. This ensures accurate labeling and adherence to nutritional claims.
• They offer services to monitor and control factors affecting DFE content, such as processing methods, storage conditions, and fortification procedures.

Food Fortification Monitoring:

• In regions with mandatory or voluntary food fortification programs for folate, Eurofins plays a crucial role in assessing the program's effectiveness. They analyze DFE levels in fortified foods to evaluate whether targeted levels are achieved and maintained.
• This data helps monitor public health initiatives and adjust fortification strategies if needed.

Research and Development:

• Eurofins contributes to advancing knowledge about folate in food by conducting research on various aspects, including:
• Identifying better methods for DFE analysis
• Understanding the impact of processing and storage on folate stability
• Investigating the bioavailability of different folate forms in food
• Developing new strategies for food fortification

References

1. Meisser-Redeuil K, Bénet S, Gimenez C, Campos-Giménez E, Maria N. Determination of folate in infant formula and adult/pediatric nutritional formula by ultra-high performance liquid chromatography-tandem mass spectrometry: First Action 2013.13. J AOAC Int. 2014 Jul-Aug;97(4):1121-6. doi: 10.5740/jaoacint.14-055. PMID: 25145147.
2. https://www.precedenceresearch.com/folate-market
3. https://www.fda.gov/food/nutrition-facts-label/folate-and-folic-acid-nutrition-and-supplement-facts-labels

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