Are folate and folic acid the same
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Understanding the Differences Between Folate and Folic Acid
Introduction to Folate and Folic Acid
Folate and folic acid are terms often used interchangeably, but they are not the same. Both are forms of vitamin B9, essential for DNA synthesis, repair, and methylation, as well as amino acid metabolism. However, their chemical structures, sources, and bioavailability differ significantly.
Chemical Structure and Sources
Folate is the naturally occurring form of vitamin B9 found in various foods such as leafy greens, fruits, and legumes. It exists in multiple forms, including tetrahydrofolate (THF) and (6S)-5-methyltetrahydrofolic acid (5-MTHF), which are biologically active and readily utilized by the body 12. On the other hand, folic acid is a synthetic form of vitamin B9, commonly used in dietary supplements and food fortification. It is more stable than natural folates, which makes it suitable for these purposes .
Bioavailability and Metabolism
The bioavailability and metabolism of folate and folic acid differ markedly. Natural folates from food are absorbed and converted into their active forms in the small intestine. In contrast, folic acid requires initial reduction and methylation in the liver to become biologically active. This process can be less efficient, especially at higher intake levels, leading to unmetabolized folic acid circulating in the bloodstream 12.
A study comparing the bioavailability of natural food folates with folic acid and (6S)-5-methyltetrahydrofolic acid found that the increase in plasma folate concentration was higher when natural folates were consumed compared to folic acid. Specifically, the relative increase in plasma folate concentration was 31% for folic acid and 39% for (6S)-5-methyltetrahydrofolic acid, indicating that natural folates and (6S)-5-methyltetrahydrofolic acid are more efficiently utilized by the body .
Clinical Implications
The differences in bioavailability and metabolism have significant clinical implications. Folic acid is widely used in supplements and fortified foods to prevent neural tube defects and other folate deficiency-related conditions. However, the potential for unmetabolized folic acid to accumulate in the bloodstream raises concerns about its long-term safety and efficacy 12.
Moreover, the use of (6S)-5-methyltetrahydrofolic acid as a reference folate in dietary intervention studies is recommended over folic acid. This is because (6S)-5-methyltetrahydrofolic acid more accurately reflects the bioavailability of natural food folates, thereby providing more reliable data on folate status and health outcomes .
Conclusion
In summary, while folate and folic acid are both forms of vitamin B9, they are not the same. Folate is the natural form found in foods, whereas folic acid is a synthetic form used in supplements and fortification. Their differences in bioavailability and metabolism have important implications for dietary recommendations and clinical practices. Understanding these differences is crucial for optimizing folate intake and improving health outcomes.
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