What Are Folate and Folic Acid?
Before determining which form of vitamin B9 is better, it's essential to understand the distinction between folate and folic acid. Folate is the general term for the naturally occurring forms of vitamin B9 found in various foods. In nature, folate exists as polyglutamates, which must be broken down by digestive enzymes before absorption. Good food sources include dark leafy greens, legumes, and liver.
On the other hand, folic acid is the synthetic (man-made) form of vitamin B9. It is a more stable compound than natural folate, making it ideal for use in dietary supplements and food fortification programs, such as enriched breads, cereals, and pasta.
How Folate and Folic Acid are Processed
One of the most significant differences lies in how the body processes each form. Natural folate from food is converted into its active form, 5-methyltetrahydrofolate (5-MTHF), primarily in the intestine. Folic acid, however, is not immediately converted and must be metabolized by an enzyme called dihydrofolate reductase (DHFR), mainly in the liver.
This conversion of folic acid is often slow and can be inefficient for some individuals. As a result, unmetabolized folic acid (UMFA) can build up in the bloodstream. While more research is needed, some evidence suggests high levels of UMFA could have potential health implications. This conversion issue is especially relevant for people with a genetic variation affecting the methylenetetrahydrofolate reductase (MTHFR) enzyme, which is involved in folate metabolism.
The MTHFR Gene and Folate Metabolism
The MTHFR gene produces the enzyme required for the final step of converting folate into its active 5-MTHF form. For individuals with a variant in this gene, the conversion process is even less efficient. This can result in lower active folate levels, even with adequate folic acid intake. For these people, taking a supplement with L-methylfolate (the active form) may be a more effective strategy to increase their active folate status.
However, it is important to note that the Centers for Disease Control and Prevention (CDC) states that folic acid supplements are effective at increasing blood folate levels, even in people with MTHFR variants, and that folic acid is the only form of folate shown to help prevent neural tube defects (NTDs). Consulting a healthcare provider is recommended for personalized advice, especially during pregnancy.
Natural Folate vs. Folic Acid Comparison
| Feature | Natural Folate (from food) | Folic Acid (synthetic) |
|---|---|---|
| Source | Found naturally in foods like leafy greens, legumes, and liver. | Man-made, used in supplements and fortified foods. |
| Bioavailability | Lower and more variable (around 50-80% of folic acid), as it's bound to food matrix. | High (about 85% from fortified foods, higher from supplements taken on empty stomach). |
| Absorption | Processed primarily in the small intestine after de-conjugation. | Absorbed directly and metabolized in the liver via the DHFR enzyme. |
| MTHFR Interaction | Does not require the specific conversion step impacted by the MTHFR variant. | Conversion process is less efficient for individuals with the MTHFR variant. |
| Stability | Unstable and easily destroyed by cooking, heat, and light. | Highly stable, which is why it is used in food fortification. |
| Potential Risks | Very difficult to get excessive amounts from diet alone. | High doses can mask a vitamin B12 deficiency and potentially lead to unmetabolized folic acid (UMFA) buildup. |
Getting Enough B9: Food Sources and Supplements
Incorporating both natural folate-rich foods and, when necessary, fortified foods or supplements is a comprehensive approach to meeting B9 requirements. For most healthy adults, a balanced diet is sufficient.
Rich sources of natural folate include:
- Dark leafy green vegetables (spinach, kale, romaine lettuce)
- Legumes (beans, peas, lentils)
- Asparagus
- Brussels sprouts
- Beef liver
- Citrus fruits (oranges, grapefruit)
Fortified foods containing folic acid:
- Enriched bread and pasta
- Fortified breakfast cereals
- Rice
The Verdict: So, is natural folate better than folic acid?
There is no single answer to the question of whether natural folate is better than folic acid, as the optimal choice is highly individual. Folic acid has been instrumental in public health campaigns to reduce neural tube defects due to its stability and high absorption rate. For women who are pregnant or planning to become pregnant, folic acid supplementation is strongly recommended based on robust scientific evidence.
However, natural folate from a diverse diet offers a broader range of nutrients and doesn't carry the risk of UMFA buildup, making it ideal for general health. For those with the MTHFR gene variant or specific health concerns, L-methylfolate (the active form) may be a more readily usable alternative, though folic acid is still effective for raising blood folate levels. Ultimately, a balanced approach combining a folate-rich diet with an appropriate supplement tailored to individual needs and health status, under the guidance of a healthcare professional, is the best strategy. For women of childbearing age, the CDC and other health organizations have a clear recommendation.
This article is for informational purposes only. You should consult with a healthcare professional before making any changes to your diet or supplement regimen. National Institutes of Health (NIH)
Potential Concerns with High Folic Acid Intake
While safe within recommended dosages, excessive intake of folic acid, primarily from supplements and fortified foods, can present a few risks. High levels of UMFA in the blood, particularly in individuals with inefficient DHFR activity, is one area of concern that needs more study. Additionally, high folic acid intake can potentially mask the neurological symptoms of a vitamin B12 deficiency, which can be a serious issue if left untreated. This is why it's important to monitor B12 levels and discuss your supplementation strategy with a doctor, especially with higher doses.
Conclusion
The choice between natural folate and folic acid isn't a simple 'better or worse' decision. Each form serves a vital role, and a person’s genetic makeup and life stage are key determinants in which is most appropriate. A diet rich in natural folate is always beneficial, providing B9 along with other important vitamins and fiber. For those planning a pregnancy, the documented benefits and stability of folic acid make it the go-to supplement. For individuals with the MTHFR gene variant or specific health considerations, the active form, methylfolate, may offer a more direct pathway for absorption and utilization. Always prioritize dietary sources and discuss your specific needs with a healthcare provider to ensure safe and effective supplementation.
