What can low folate cause? Understanding Deficiency and Its Health Impacts

January 7, 2026 •

4 min read

The body stores only a small amount of folate, meaning a diet lacking this B vitamin can lead to a deficiency within just a few months. Understanding what can low folate cause is critical for preventing serious health issues, as this vitamin plays a crucial role in cell growth, DNA synthesis, and red blood cell production.

Quick Summary

A lack of folate can result in megaloblastic anemia, severe birth defects, neurological issues like depression, and an increased risk of heart disease. It affects overall cellular function and impacts multiple body systems, particularly during periods of rapid growth.

Key Points

Anemia: Low folate is a common cause of megaloblastic anemia, leading to large, abnormal red blood cells and symptoms like fatigue, weakness, and paleness.
Pregnancy Complications: Deficiency before and during pregnancy significantly increases the risk of serious neural tube defects in the fetus, such as spina bifida and anencephaly.
Mental Health: Inadequate folate levels are linked to a higher risk of depression, anxiety, cognitive impairment, and more severe depressive symptoms.
Cardiovascular Disease: Folate deficiency can elevate homocysteine levels in the blood, an independent risk factor for heart disease and vascular issues.
Neurological Symptoms: Beyond mental health, a lack of folate can cause physical neurological symptoms like numbness, muscle weakness, and problems with memory and judgment.
Diet and Absorption: Common causes include poor diet, excessive alcohol use, certain medications, and malabsorption disorders like Crohn's disease.

The Fundamental Role of Folate

Folate, or vitamin B9, is a water-soluble vitamin essential for a wide range of bodily functions. Its synthetic form, folic acid, is often added to fortified foods and supplements. Your body needs folate to create and repair DNA, produce red and white blood cells, and synthesize vital proteins. When a deficiency occurs, these processes are disrupted, leading to a cascade of health problems that can range from mild fatigue to serious, long-term complications.

Key Health Consequences of Low Folate

Low folate levels have a systemic impact, affecting multiple organ systems due to its fundamental role in cellular health. Some of the most significant consequences include blood disorders, developmental issues, and neurological problems.

Megaloblastic Anemia

One of the most common outcomes of a folate deficiency is megaloblastic anemia, a condition where the body produces abnormally large, immature, and fewer red blood cells. These large red blood cells, known as megaloblasts, do not function properly and often have a shorter lifespan, leading to reduced oxygen transport throughout the body.

Symptoms of folate-deficiency anemia can include:

Extreme fatigue and weakness
Pale skin
Shortness of breath
Dizziness or lightheadedness
Headaches
Irritability
Racing or pounding heartbeats

Severe Complications During Pregnancy

Folate is especially critical during periods of rapid growth, such as pregnancy. An adequate intake of folic acid before and during early pregnancy is vital to prevent severe birth defects of the baby's brain and spine, known as neural tube defects (NTDs). These can include:

Spina bifida: A condition where the spinal column doesn't fully close, leaving the spinal cord exposed and often causing lifelong disabilities.
Anencephaly: A fatal condition where major parts of the brain and skull fail to develop. In addition to NTDs, low folate can increase the risk of other pregnancy complications like premature birth, low birth weight, and placental abruption.

Neurological and Mental Health Issues

Folate plays a role in the synthesis of neurotransmitters that regulate mood, such as serotonin and dopamine. Consequently, low folate levels are strongly linked to psychological problems, including:

Depression and anxiety
Difficulty with memory, understanding, and judgment (cognitive impairment)
Confusion and, in severe cases, dementia
Irritability and mood swings Some research even suggests that low folate levels may contribute to increased suicidal behavior in individuals with depressive disorders.

Cardiovascular Health Risks

Folate is necessary for the metabolism of the amino acid homocysteine. A deficiency disrupts this process, leading to elevated homocysteine levels, or hyperhomocysteinemia. High homocysteine is recognized as an independent risk factor for cardiovascular disease and atherothrombosis. Complications can include:

An abnormally fast heartbeat (tachycardia)
Heart failure in severe anemia cases
Increased risk of heart conditions and vascular dysfunction

Comparison of Folate Deficiency vs. Vitamin B12 Deficiency

Low levels of both folate and vitamin B12 can cause similar symptoms, making a proper diagnosis crucial. Here is a comparison of their key differences:


Feature	Folate Deficiency	Vitamin B12 Deficiency
Dietary Source	Primarily found in plants like leafy greens, beans, and fortified grains.	Primarily found in animal products like meat, eggs, and dairy.
Body Storage	Body stores are small and can be depleted within a few months.	Body can store a multi-year supply, so deficiency may take longer to develop.
Red Blood Cell Effect	Leads to megaloblastic anemia with large, immature red blood cells.	Also causes megaloblastic anemia.
Neurological Damage	Associated with depression, cognitive issues, and mood changes.	Can cause more severe neurological damage, potentially permanent, including memory loss, paranoia, and nerve damage (pins and needles).
Risk Groups	Pregnant people, excessive alcohol users, people with malabsorption disorders.	Vegans, older adults, people with pernicious anemia.
Treatment Consideration	Treating B12 deficiency with folate can mask the B12 issue, potentially worsening nerve damage.	Treatment requires addressing the B12 deficit directly, possibly with injections.

Addressing and Preventing Folate Deficiency

The primary way to address and prevent low folate is by increasing your intake through a balanced diet or supplementation. The Food and Drug Administration (FDA) has required the fortification of many grain products with folic acid, which has helped reduce deficiency rates.

Dietary Sources of Folate

Incorporating a variety of folate-rich foods into your diet is an effective strategy. Good sources include:

Leafy green vegetables (spinach, romaine lettuce, mustard greens)
Legumes (black-eyed peas, kidney beans, chickpeas)
Fortified cereals, breads, rice, and pasta
Fruits (oranges, papaya, cantaloupe)
Beef liver
Asparagus and Brussels sprouts

Risk Factors and Underlying Causes

Several factors can increase a person's risk of developing a deficiency, including:

Diet: An unbalanced diet or prolonged overcooking of foods, which destroys folate.
Alcohol Use: Excessive alcohol consumption can interfere with folate absorption and metabolism.
Malabsorption Disorders: Conditions like Crohn's disease or celiac disease can hinder the body's ability to absorb folate.
Certain Medications: Some anti-seizure drugs, rheumatoid arthritis medications (methotrexate), and medications for ulcerative colitis can interfere with folate absorption.
Increased Demand: The body requires more folate during pregnancy, lactation, and infancy.
Genetics: An MTHFR polymorphism is a genetic variation that impairs the body's ability to convert folate into its active form, affecting about 10-25% of certain populations.

Conclusion

Low folate levels, though preventable, can lead to serious health problems affecting the blood, nervous system, and cardiovascular system. From the widespread issue of megaloblastic anemia to the critical developmental risks during pregnancy and potential impacts on mental health, the consequences of deficiency are significant. Fortunately, a balanced diet rich in leafy greens, legumes, and fortified grains can help maintain adequate levels. For those at higher risk, including pregnant individuals and those with malabsorption issues, supplementation may be necessary under medical guidance. If you experience persistent symptoms like fatigue or cognitive issues, it is essential to consult a healthcare provider for a proper diagnosis and treatment plan.

For more detailed information on folate recommendations and dietary sources, visit the National Institutes of Health (NIH) Office of Dietary Supplements' fact sheet on folate.

Frequently Asked Questions

The initial signs of low folate often include general symptoms of anemia, such as persistent fatigue, lack of energy, and muscle weakness. Other early indicators can be paleness, shortness of breath, and irritability.

Yes, if left untreated, low folate can lead to serious health complications. These include megaloblastic anemia, neurological problems, and an increased risk of cardiovascular disease. For pregnant women, it poses a significant risk of severe birth defects.

Folate deficiency is typically diagnosed through a blood test that measures folate levels. A complete blood count (CBC) test can also reveal abnormally large red blood cells, which is a characteristic sign of megaloblastic anemia.

Treatment usually involves increasing folate intake through dietary changes and taking folic acid supplements. For most people, consuming more folate-rich foods like leafy greens and fortified grains is sufficient, but supplements can be necessary to correct a deficiency quickly.

Yes, low folate levels have been linked to mood disorders such as depression and anxiety. Folate is involved in producing brain neurotransmitters that regulate mood, so an insufficient supply can disrupt this balance.

Excellent sources of naturally occurring folate include dark leafy greens like spinach, asparagus, and Brussels sprouts, as well as legumes such as black-eyed peas and kidney beans. Many grain products are also fortified with folic acid, the synthetic form of folate.

People most at risk for folate deficiency include pregnant women, individuals with malabsorption disorders like celiac or Crohn's disease, those who consume excessive alcohol, and people taking certain medications. Some individuals with a genetic mutation (MTHFR polymorphism) also have difficulty processing folate.