Understanding the Causes of Low Folic Acid in Your Diet

According to the CDC, mandatory fortification of grains with folic acid has dramatically reduced deficiency rates in many developed countries, yet deficiency can still occur. So, what is the main cause of low folic acid? The answer is often a combination of factors, but it most commonly stems from an inadequate diet that lacks folate-rich foods.

Quick Summary

This article explores the primary drivers behind low folic acid, detailing how inadequate dietary intake, impaired absorption from gastrointestinal conditions, certain medications, and increased physiological needs contribute to deficiency. Learn about the symptoms and discover strategies to prevent and manage low folate levels effectively.

Key Points

• Inadequate Diet: Not eating enough folate-rich foods like leafy greens, citrus fruits, and legumes is the most common cause of low folic acid.

• Malabsorption Issues: Conditions like celiac disease, Crohn's disease, and surgical procedures can impair the intestine's ability to absorb folate.

• Certain Medications: Drugs such as methotrexate, some anticonvulsants, and sulfasalazine can interfere with folate absorption and metabolism.

• Increased Physiological Needs: Pregnancy, lactation, and certain chronic illnesses like hemolytic anemia significantly increase the body's demand for folate.

• Genetic Factors: Inherited gene variants, particularly in the MTHFR gene, can reduce the body's efficiency in converting folic acid to its active form.

• Overcooking Foods: Since folate is water-soluble and sensitive to heat, overcooking vegetables can destroy a large percentage of their folate content.

• Excessive Alcohol: Chronic heavy alcohol use disrupts folate absorption and increases its excretion from the body.

• Masked Deficiency: High doses of folic acid can mask a coexisting vitamin B12 deficiency, potentially leading to irreversible neurological damage if not correctly diagnosed.

What is the primary cause of low folic acid?

For most people, the primary cause of low folic acid is an insufficient intake of folate-rich foods. Folate, the naturally occurring form of the vitamin, is water-soluble, meaning the body does not store it for long periods and requires a consistent daily supply from the diet. If a person's diet is lacking in fresh fruits, vegetables, legumes, and fortified grains, their folate stores can become depleted in just a few weeks. This is particularly common in individuals who consume an unhealthy or restrictive diet, or who regularly overcook their vegetables, as heat can destroy up to 95% of the natural folate content.

Dietary factors contributing to folate deficiency

• Low consumption of fresh produce: Diets lacking in leafy green vegetables, citrus fruits, and legumes are a direct route to deficiency.
• Overcooking food: Prolonged cooking with high heat can degrade a significant portion of the natural folate in vegetables. Steaming or microwaving can help retain more nutrients.
• Alcohol consumption: Excessive alcohol intake interferes with the absorption and metabolism of folate, and people with chronic alcohol use disorder often have poor overall nutrition.
• Restrictive or unbalanced diets: People following certain fad diets or those with general undernourishment may not receive the necessary daily folate intake.

Medical conditions that impair absorption

Even with a diet rich in folate, certain medical conditions can prevent the body from properly absorbing or utilizing the vitamin, leading to deficiency. These are often related to the digestive system, where folate is absorbed.

Malabsorption disorders

• Celiac disease: An autoimmune disorder where consuming gluten damages the small intestine lining, impairing nutrient absorption.
• Crohn's disease and other inflammatory bowel diseases: Inflammation of the digestive tract can reduce the body's ability to absorb folate.
• Bariatric surgery: Surgical procedures that alter the digestive tract, such as gastric bypass, can interfere with normal nutrient uptake.
• Hereditary folate malabsorption (HFM): A rare genetic disorder caused by a mutation in the SLC46A1 gene, which severely impairs the body's ability to absorb folate from the intestines and transport it into the brain.

Medications and genetic factors impacting folate levels

Several other non-dietary factors play a significant role in causing low folic acid. These can interfere with the vitamin's metabolism and absorption or increase the body's need for it.

Medications that lower folate

Many medications can interfere with folate metabolism, causing or exacerbating a deficiency. This is often monitored by doctors, who may prescribe supplements to counteract the effect.

• Methotrexate: A drug used to treat cancer and certain autoimmune diseases like rheumatoid arthritis, it functions by blocking the enzyme that activates folate.
• Anticonvulsants: Medications such as phenytoin and phenobarbital, used for seizures, can decrease folate levels.
• Sulfasalazine: Used for ulcerative colitis and rheumatoid arthritis, it interferes with folate absorption.
• Trimethoprim: An antibiotic that can also affect folate metabolism.

Genetic variations affecting folate use

Some individuals have a genetic variation that affects how their body processes folic acid.

• MTHFR gene variant: A mutation in the methylenetetrahydrofolate reductase (MTHFR) gene can reduce the body's ability to convert synthetic folic acid into its active, usable form, 5-methyltetrahydrofolate (5-MTHF). While a common variant, the Centers for Disease Control and Prevention (CDC) still recommend folic acid supplementation for pregnancy, regardless of MTHFR status. However, some doctors may recommend 5-MTHF for those with this mutation.

Increased physiological demand

During certain life stages or due to particular medical conditions, the body's need for folate increases dramatically, potentially leading to a deficiency if not properly supplemented.

Pregnancy and lactation

• Rapid cell division and growth during pregnancy and fetal development require a significantly higher intake of folate. A deficiency in early pregnancy is linked to a higher risk of neural tube defects like spina bifida.
• Lactating women also have an increased need to support breast milk production.

Chronic health issues

• Chronic hemolytic anemia: The rapid destruction and turnover of red blood cells significantly increase the body's need for folate.
• Kidney dialysis: This treatment for kidney failure can lead to folate loss, necessitating supplementation.
• Exfoliative dermatitis and other skin disorders: Conditions involving heightened cell regeneration increase the body's demand for folate.

Comparison of major causes of low folic acid

Cause Category	Primary Mechanism	High-Risk Groups	Prevention/Treatment Approach
Inadequate Diet	Insufficient intake of folate from foods like leafy greens, legumes, and fortified grains.	Individuals with poor nutrition, unbalanced diets, heavy alcohol users, people who overcook vegetables.	Increase consumption of raw or lightly cooked folate-rich foods and fortified grains. Reduce alcohol intake.
Malabsorption	Conditions affecting the digestive tract, preventing proper nutrient absorption.	Those with celiac disease, Crohn's disease, inflammatory bowel disease, or who have had bariatric surgery.	Treat the underlying medical condition. May require oral supplements or injections under medical supervision.
Medications	Certain drugs interfere with the absorption or metabolism of folate.	Patients taking methotrexate, some anticonvulsants (e.g., phenytoin), or sulfasalazine.	Regular monitoring by a doctor; may require folic acid supplementation alongside medication.
Increased Physiological Need	The body's demand for folate is higher than normal due to rapid cell growth.	Pregnant women, lactating women, people with chronic hemolytic anemia, and those on kidney dialysis.	Folic acid supplementation to meet increased requirements.
Genetic Factors	Inherited gene variants, like MTHFR, affect the conversion of folate to its active form.	Individuals with MTHFR gene variants, particularly those who are homozygous for the C677T mutation.	Folic acid supplementation is generally effective, but some individuals may benefit from the active form, 5-MTHF, as advised by a doctor.

Conclusion

While inadequate dietary intake remains the most common and often easiest-to-address cause of low folic acid, a variety of other factors can also be at play. Medical conditions that hinder absorption, certain prescription medications, increased physiological needs during life stages like pregnancy, and genetic predispositions can all contribute to a deficiency. Understanding these underlying causes is crucial for effective prevention and treatment. For most, ensuring a balanced diet rich in leafy greens, legumes, and fortified grains is key. However, for those with specific health issues, working with a healthcare provider to determine the best course of action, which may include targeted supplementation, is the most appropriate approach. This personalized strategy helps correct the deficiency and mitigates potential health complications, reinforcing the vital role of folate in overall well-being. For more detailed information on folate metabolism, the NIH provides extensive resources.

Frequently Asked Questions

What is the fastest way to raise folic acid levels?

The fastest way to raise folic acid levels is through oral supplements, which are more readily absorbed by the body than folate from food. In severe cases, a doctor might recommend intramuscular injections. Always consult a healthcare provider to ensure it does not mask an underlying vitamin B12 deficiency.

Which foods should I eat to increase my folate intake?

To increase folate intake, focus on leafy green vegetables like spinach and kale, legumes such as lentils and chickpeas, citrus fruits like oranges, and fortified grain products like bread, cereal, and rice.

Can I have low folic acid even if I eat a healthy diet?

Yes. While an inadequate diet is the most common cause, conditions like celiac disease or Crohn's disease, certain medications, or genetic variations can prevent your body from absorbing or using folate efficiently, even with a healthy diet.

How does alcohol affect folic acid levels?

Excessive alcohol consumption can lead to low folic acid levels in two ways: it often replaces a healthy diet, leading to poor intake, and it interferes with the absorption and metabolism of folate in the body.

What are the symptoms of low folic acid?

Symptoms of low folic acid, which can lead to megaloblastic anemia, include fatigue, weakness, mouth sores, a sore and red tongue, irritability, and in severe cases, diarrhea and depression.

Is it true that cooking can destroy folate?

Yes. Folate is a water-soluble vitamin that is sensitive to heat. High-temperature and prolonged cooking, especially boiling, can destroy a significant percentage of the natural folate in foods. Steaming or eating raw vegetables can help preserve the content.

What is the connection between MTHFR and folic acid deficiency?

A common genetic mutation in the MTHFR gene can make it harder for the body to convert synthetic folic acid into its active form. While most people with this variant can still process folate, some may benefit from a supplement with the active form, 5-MTHF.