Should I Take Folic Acid and Vitamin D? A Comprehensive Guide

October 11, 2025 •

5 min read

According to the NHS, women who could become pregnant should take a daily folic acid supplement to help prevent birth defects. But the question, "Should I take folic acid and vitamin D?" applies to more than just prospective parents, influencing general health for many individuals.

Quick Summary

This guide provides an overview of why and when folic acid and vitamin D supplements are recommended, their distinct roles in the body, and who may need them. It details specific populations who can benefit and the importance of consulting a healthcare professional.

Key Points

Folic acid prevents birth defects: Women who are pregnant or may become pregnant should take a daily folic acid supplement to prevent neural tube defects like spina bifida.
Vitamin D supports bone health: All adults, especially in winter or with limited sun exposure, should consider a vitamin D supplement to help the body absorb calcium for healthy bones.
Intake amounts vary by need: The recommended folic acid intake can vary, and different amounts may be necessary for some individuals with specific risk factors.
High amounts can be harmful: Excessive folic acid can mask a vitamin B12 deficiency, potentially leading to nerve damage. Vitamin D toxicity can cause dangerously high calcium levels.
Consult a professional: Always speak with a doctor or qualified healthcare provider to determine the appropriate amount and suitability of these supplements for your individual health needs.
Folic acid is for more than pregnancy: It also helps prevent anemia and lower high homocysteine levels, which is linked to heart disease.
Sunlight is a key source of Vitamin D: The body produces vitamin D when skin is exposed to sunlight, but during darker months or for those with darker skin, supplements are often required.

Understanding the Roles of Folic Acid and Vitamin D

Folic acid and vitamin D are two critical nutrients, each playing a vital, yet distinct, role in maintaining health. Folic acid, the synthetic form of folate (vitamin B9), is essential for cell growth, DNA synthesis, and red blood cell formation. Vitamin D, sometimes called the "sunshine vitamin," is crucial for bone health by helping the body absorb calcium and phosphate. While a balanced diet can provide many nutrients, supplements are often necessary to ensure adequate intake of these two. A common scenario for needing both supplements is during pregnancy, but there are other reasons to consider them.

Folic Acid's Function and Recommendations

Folic acid is perhaps most recognized for its role in preventing neural tube defects (NTDs), such as spina bifida, during early pregnancy. The neural tube develops into the baby's brain and spinal cord in the first month of pregnancy, often before a person even knows they are pregnant. This is why public health bodies recommend that all women of childbearing age take a daily folic acid supplement. While a common recommendation is to take a specific amount daily for many individuals, some individuals with higher risk factors, like a family history of NTDs or diabetes, may need a different amount, prescribed by a doctor. Folic acid is a water-soluble vitamin, meaning the body does not store it and requires daily replenishment through diet or supplements.

Beyond pregnancy, folic acid helps manage other health issues. It is effective in lowering high levels of homocysteine in the blood, which has been linked to a higher risk of heart disease and stroke. It can also help treat folate deficiency anemia, leading to fatigue and weakness. Folate occurs naturally in foods like leafy greens, citrus fruits, and beans, but synthetic folic acid from supplements and fortified foods is more easily absorbed by the body.

Vitamin D's Function and Recommendations

Vitamin D is a fat-soluble vitamin primarily produced by the body when skin is exposed to sunlight. It is critical for regulating calcium and phosphate levels, which are vital for strong bones, teeth, and muscles. A deficiency can lead to bone-softening conditions like rickets in children and osteomalacia in adults.

Because sun exposure varies by season and location, many health organizations recommend vitamin D supplementation. In many parts of the world, a daily supplement is advised during the autumn and winter months. For those with limited sun exposure due to lifestyle (spending a lot of time indoors) or skin tone (darker skin produces less vitamin D from sunlight), year-round supplementation may be necessary. A commonly recommended daily intake for most adults, including pregnant and breastfeeding women, is a specific amount.

When You Might Need Both Folic Acid and Vitamin D

Certain situations increase the necessity for taking both supplements simultaneously.

Pregnancy and Preconception: This is the most widely recognized scenario. Women trying to conceive and those in the first trimester should take a daily folic acid supplement. At the same time, because vitamin D needs increase during pregnancy for proper fetal development, a daily supplement is also recommended, especially during months with limited sunlight.
Certain Health Conditions: People with conditions that affect nutrient absorption, such as Celiac disease or Inflammatory Bowel Disease (IBD), may require both supplements to address deficiencies.
Lifestyle Factors: Individuals with limited sun exposure (due to indoor work or covering up for cultural reasons) who also follow a restricted diet may need to supplement both. Vegan diets, for instance, can be low in vitamin D, making supplementation important.
Cognitive Support: Emerging research suggests a potential link between deficiencies in these vitamins and cognitive function. One study highlighted how co-supplementation of vitamin D, folic acid, and vitamin B12 helped reverse learning and memory impairment in animal models.

Comparison of Folic Acid vs. Vitamin D


Feature	Folic Acid (Vitamin B9)	Vitamin D
Primary Function	Cell growth, DNA synthesis, red blood cell formation, prevents neural tube defects.	Calcium absorption, bone mineralization, immune function.
Source	Supplements, fortified foods (cereals, pasta), natural folate in leafy greens, citrus, beans.	Sunlight exposure, fatty fish, egg yolks, fortified milk and cereal, supplements.
Solubility	Water-soluble; not stored in the body long-term, requires regular intake.	Fat-soluble; stored in fat tissue for a longer period.
Deficiency Risks	Anemia, fatigue, weakness; increased risk of NTDs in babies.	Bone pain, muscle weakness, frequent infections, rickets (children), osteomalacia (adults).
Pregnancy Role	Critical for preventing brain and spinal cord birth defects in early pregnancy.	Essential for fetal bone and tooth development; prevents pre-eclampsia and low birth weight.

Risks and Considerations for Supplementation

While both vitamins are essential, taking excessive amounts can be harmful, and supplementation should always be managed carefully. For folic acid, high intake can mask a vitamin B12 deficiency, leading to irreversible neurological damage if not caught and treated. High folic acid intake has also been linked with other side effects, including stomach upset and potential interactions with certain medications, such as those for epilepsy. Vitamin D toxicity is rare but serious, caused by taking large amounts of supplements over a long period. This can lead to hypercalcemia, which can cause symptoms like nausea, weakness, excessive thirst, and kidney damage. It is crucial to adhere to recommended daily allowances unless otherwise directed by a healthcare provider.

Conclusion

For many, especially women of childbearing age, pregnant individuals, and those with limited sun exposure, taking both folic acid and vitamin D is a recommended strategy to support overall health and prevent serious complications. However, the decision should be personalized and made in consultation with a healthcare professional, who can assess individual needs based on diet, lifestyle, and medical history. While supplements offer a reliable way to meet nutritional gaps, they should not replace a healthy, varied diet. Prioritizing a discussion with your doctor ensures that you are taking the right amounts for your specific situation, balancing the benefits while mitigating any potential risks associated with supplementation.

[Medical Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition or before taking any new supplement.]

Frequently Asked Questions

Women who are pregnant, trying to conceive, or could become pregnant are strongly advised to take a daily folic acid supplement. It is also recommended they take a vitamin D supplement during pregnancy and breastfeeding. People with certain malabsorption issues, dark skin, or minimal sun exposure also often require these supplements.

Folic acid is essential for forming healthy red blood cells, synthesizing DNA, and promoting cell growth. Its most crucial role is preventing severe birth defects of the brain and spinal cord, known as neural tube defects, in developing babies.

Vitamin D's main function is to help the body absorb calcium and phosphate, which are vital for building and maintaining strong bones, teeth, and muscles. It also plays a role in immune function.

While some foods naturally contain folate and vitamin D, or are fortified with them, it is difficult to get the recommended amounts from diet alone, especially for high-risk groups like pregnant women. Supplements are generally recommended to ensure adequate intake.

Taking excessively high amounts of folic acid can mask the neurological symptoms of a vitamin B12 deficiency, which, if left untreated, can lead to permanent nerve damage. Other side effects can include nausea and stomach upset.

While rare, excessive intake of vitamin D from supplements can lead to vitamin D toxicity, which can cause dangerously high calcium levels (hypercalcemia). Symptoms include nausea, increased urination and thirst, weakness, and potential heart or kidney damage.

For women trying to conceive, it's recommended to start folic acid ideally at least one month before conception and continue through the first 12 weeks of pregnancy. Vitamin D is often advised during the autumn and winter months, or year-round for some individuals.