Understanding the Nutritional Link: What Vitamin Deficiency Can Cause Spina Bifida?

October 3, 2025 •

3 min read

According to the Centers for Disease Control and Prevention (CDC), sufficient folate levels in the body are crucial for preventing neural tube defects. A significant risk factor for spina bifida is a specific vitamin deficiency, which can be mitigated through proper nutrition and supplementation.

Quick Summary

A lack of folic acid, a B vitamin essential for fetal development, is the primary nutritional risk factor for spina bifida. This guide explores the roles of folic acid and vitamin B12 in prevention, along with dietary strategies and supplementation advice.

Key Points

Folic Acid (Vitamin B9) is Key: A deficiency in folic acid is the most important and preventable nutritional risk factor for spina bifida.
Start Supplementing Early: The neural tube closes within the first month of pregnancy, so supplementation should begin at least one month prior to conception.
Folic Acid vs. Folate: Folic acid, the synthetic form of the vitamin, is more easily absorbed by the body than natural folate found in foods.
Vitamin B12 is a Cofactor: Adequate vitamin B12 is necessary for the body to properly metabolize and utilize folic acid, so B12 deficiency can also increase risk.
High-Risk Individuals Need More: Women with a family history of neural tube defects or who have had a previous NTD-affected pregnancy require a higher prescribed amount of folic acid, as determined by a healthcare provider.
Consider All Risk Factors: Beyond vitamins, risk factors like genetics, certain medications, diabetes, and obesity should also be addressed to reduce the chance of spina bifida.

The Critical Role of Folic Acid (Vitamin B9)

Folic acid, the synthetic form of vitamin B9, is undeniably the most important vitamin in the context of preventing spina bifida. Spina bifida is a type of neural tube defect (NTD) that occurs very early in pregnancy, often before a woman is even aware she is pregnant. The neural tube is the embryonic structure that develops into the baby's brain and spinal cord. If this tube fails to close completely around day 28 after conception, it can result in an NTD.

Folic acid plays a vital role in cell proliferation and DNA synthesis, which are critical for the rapid growth and development of the neural tube. By ensuring adequate levels of folic acid, the risk of NTDs, including spina bifida, can be dramatically reduced. Studies suggest that taking folic acid supplements before conception and throughout the first trimester can prevent many cases of NTDs.

Folic Acid vs. Folate

It is important to distinguish between folate, the natural form of vitamin B9 found in food, and folic acid, the synthetic version used in supplements and fortified foods. While both contribute to overall B9 levels, the body absorbs folic acid more readily. For this reason, fortification of grains and daily supplementation are methods often used for ensuring sufficient intake.

The Supporting Function of Vitamin B12 (Cobalamin)

While folic acid is the main player, research also points to the importance of vitamin B12 in the prevention of spina bifida. Vitamin B12 is essential for the metabolism of folic acid, and a deficiency in B12 can interfere with the body's ability to utilize folate effectively. Low maternal vitamin B12 status has been linked to an increased risk of having a child with spina bifida, suggesting a synergistic relationship between these two vitamins. Maintaining adequate levels of both vitamins is crucial for optimal prevention.

The Vitamin B12-Folate Connection

B12 acts as a cofactor for the enzyme methionine synthase, which is necessary for converting folate to its active form. Without sufficient B12, a 'folate trap' can occur, where folate becomes metabolically inactive despite being present in the body. This metabolic issue can hinder the development of the neural tube, highlighting why both nutrients are important for fetal health.

Nutritional Strategies and Supplementation

For women of childbearing age, obtaining sufficient folic acid through diet and supplementation is paramount. Health organizations often recommend a specific daily intake of folic acid for women who could become pregnant.

Food Sources of Folate and Folic Acid

Folate-rich foods: Dark green leafy vegetables (spinach, kale, broccoli), legumes (lentils, chickpeas), citrus fruits (oranges), avocados, eggs, and liver.
Fortified foods (containing folic acid): Enriched grains like bread, pasta, rice, and breakfast cereals.

Higher Dose Considerations

Certain individuals may require a higher amount of folic acid, as prescribed by a healthcare provider. This includes women with a family history of NTDs, those who have previously had a pregnancy affected by an NTD, or women with pre-existing conditions like diabetes.

Other Contributing Risk Factors

While vitamin deficiency is a key preventable cause, other factors can increase the risk of spina bifida.


Factor	Impact on Risk
Family History of NTDs	Significantly increases risk; may require specific folic acid supplementation strategies as advised by a healthcare provider.
Certain Medications	Anti-seizure drugs like valproic acid can interfere with folate metabolism.
Diabetes	Poorly controlled blood sugar levels increase risk; requires proactive management before conception.
Obesity	Pre-pregnancy obesity is associated with an increased risk of NTDs.
Maternal Overheating	Fever, hot tubs, and saunas in early pregnancy may increase risk.
MTHFR Gene Variant	Can affect how the body processes folate, potentially necessitating a specific type of folate or adjusted intake as recommended by a healthcare provider.

Conclusion

In conclusion, a deficiency in folic acid is the most critical and well-established nutritional cause of spina bifida. The best strategy for prevention is ensuring adequate folic acid intake through supplements and fortified foods, ideally starting at least one month before conception and continuing through the first trimester. While a balanced diet rich in natural folate is beneficial, supplementation is often necessary due to the higher absorption rate of folic acid and the unpredictability of pregnancy timing. For those at higher risk, a physician-prescribed higher amount may be required. Combining this with proper management of other risk factors and adequate vitamin B12 ensures the best possible outcome for fetal neural development. For further guidance on the importance of folic acid, refer to the CDC's resources.

Frequently Asked Questions

Health organizations typically recommend a specific daily intake of folic acid for women of childbearing age. Individuals at higher risk may require a different amount, as advised by a healthcare professional.

While a diet rich in folate-containing foods is beneficial, most women do not get enough through diet alone. Because folic acid from supplements and fortified foods is better absorbed, daily supplementation is often recommended to ensure adequate intake for prevention.

The neural tube closes within the first month of pregnancy, before many women know they are pregnant. Therefore, it is critical to take folic acid supplements starting at least one month before trying to conceive and continuing through the first 12 weeks of pregnancy.

If you find out you are pregnant and haven't been taking folic acid, you should start immediately. However, the most critical period for neural tube development has passed. This is why daily supplementation for all women of childbearing age is strongly advised.

Vitamin B12 is a cofactor that helps the body metabolize folic acid. A marginal B12 deficiency can impair the body's ability to use folate, thereby increasing the risk of spina bifida, particularly when combined with low folate intake.

The MTHFR gene variant can affect how the body processes folic acid. If you have this variant and are planning a pregnancy, it is important to discuss your supplementation strategy with a healthcare provider, who may recommend a specific form of folate or adjusted intake.

Yes, many prenatal vitamins contain an amount of folic acid that aligns with health recommendations. Taking a prenatal vitamin can be a way to support consistent daily intake, especially if you are actively trying to conceive.