What Happens When You Have Too Little Folate?

November 28, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), many women of childbearing age do not get enough folic acid, the synthetic form of folate. This critical B vitamin is essential for producing red blood cells and creating DNA, meaning a deficiency can lead to a wide range of serious health problems. Understanding what happens when you have too little folate is crucial for prevention and early treatment.

Quick Summary

A lack of folate, or vitamin B9, in the body can cause megaloblastic anemia, fatigue, and weakness. Severe deficiency may lead to serious complications including birth defects, cognitive issues, and fertility problems. A balanced diet and supplements can help address the issue.

Key Points

Megaloblastic Anemia: A shortage of folate impairs red blood cell production, causing abnormally large, ineffective red blood cells and leading to fatigue and weakness.
Pregnancy Risks: During pregnancy, a folate deficiency dramatically increases the risk of neural tube defects like spina bifida and anencephaly, which affect the fetal brain and spine.
Neurological Issues: Severe or long-term deficiency can cause serious neurological symptoms, including memory loss, confusion, and peripheral neuropathy.
Diverse Causes: Low folate can result from poor diet, increased bodily demand (e.g., pregnancy), malabsorption diseases, excessive alcohol use, or certain medications.
Masking a B12 Deficiency: Treating folate deficiency with supplements alone can mask an underlying vitamin B12 deficiency, potentially worsening irreversible nerve damage.
Reversible with Treatment: Most cases are easily treated with folic acid supplements and dietary changes, but underlying causes must also be addressed.

What is Folate and Why is it Essential?

Folate, also known as vitamin B9, is a water-soluble vitamin vital for numerous bodily functions. It plays a critical role in producing red blood cells and helps form DNA and other genetic material. Because the body stores only a small amount of folate, a diet lacking in this vitamin can lead to a deficiency in just a few months. Its synthetic counterpart, folic acid, is often added to fortified foods and used in supplements because it is more easily absorbed by the body.

The Early and Common Signs of Folate Deficiency

Many of the initial symptoms of low folate are related to the development of megaloblastic anemia, a condition where red blood cells are abnormally large and immature. As a result, they cannot carry oxygen effectively throughout the body, leading to a host of noticeable symptoms.

Fatigue and Weakness: A primary symptom, leaving individuals feeling unusually tired, drained of energy, and weak.
Oral Symptoms: These can include a sore and red tongue, mouth ulcers, and a reduced sense of taste.
Pale Skin: A noticeable paleness can occur due to the reduced number of healthy red blood cells.
Irritability and Mood Changes: Emotional and psychological changes, such as irritability and depression, can signal a folate deficiency.
Gastrointestinal Issues: Diarrhea and weight loss are also common symptoms.

Serious Consequences of Untreated Low Folate

While the initial symptoms can be a nuisance, a prolonged deficiency can escalate into more severe and sometimes irreversible health issues.

Neurological Complications: Without enough folate, the nervous system can be affected. Severe deficiency may result in confusion, memory loss, and difficulty with judgment. Some research also links low folate to an increased risk of dementia.
Cardiovascular Disease: Elevated levels of homocysteine, an amino acid, are associated with low folate. This can increase the risk of heart disease.
Fertility Issues: Folate deficiency can lead to temporary infertility, which typically resolves with proper treatment.
Cancer Risk: Some studies suggest that long-term folate deficiency may increase the risk of certain cancers.

The Critical Role of Folate During Pregnancy

Perhaps the most well-known risk of low folate is its effect during pregnancy. Folate is crucial for the healthy development of a fetus's brain and spinal cord during the first few weeks of gestation, often before a woman is even aware she is pregnant.

Neural Tube Defects (NTDs): An inadequate folate intake during pregnancy drastically increases the risk of serious birth defects like spina bifida and anencephaly.
Placental Abruption: A deficiency can also heighten the risk of placental abruption, a serious condition where the placenta detaches from the uterine wall.
Other Complications: Low folate is also linked to premature birth and low birth weight in infants.

What are the Common Causes of Folate Deficiency?

Deficiency can arise from several factors, often a combination of poor diet and underlying health conditions.

Inadequate Dietary Intake: The most common cause is simply not eating enough folate-rich foods like green leafy vegetables, legumes, and citrus fruits. Overcooking food can also destroy its natural folate content.
Increased Bodily Needs: Women who are pregnant or breastfeeding and people with certain blood disorders, like sickle cell anemia, have a higher demand for folate.
Malabsorption Issues: Conditions affecting the digestive tract, such as celiac disease and Crohn's disease, can impair the body's ability to absorb folate.
Excessive Alcohol Consumption: Alcohol interferes with the absorption and metabolism of folate.
Certain Medications: Some drugs, including certain anti-seizure medications and those for ulcerative colitis, can interfere with folate absorption.

Diagnosis and Treatment for Low Folate

Diagnosing a folate deficiency typically involves a physical exam, a review of symptoms, and blood tests to measure serum folate levels.

Supplements: Treatment almost always includes daily oral folic acid tablets to replenish the body's stores. In severe cases or for individuals with malabsorption issues, injections may be necessary.
Dietary Adjustments: Your healthcare provider will likely recommend increasing your intake of folate-rich foods, including asparagus, broccoli, chickpeas, and fortified grains.
Addressing Underlying Issues: If the deficiency is caused by a medical condition, that condition must also be treated.

Comparison of Folate vs. Vitamin B12 Deficiency

It's important to differentiate between folate and vitamin B12 deficiencies, as they share similar symptoms and B12 deficiency can be masked by folate treatment.


Feature	Folate Deficiency	Vitamin B12 Deficiency
Symptom Onset	Can develop within a few weeks due to low bodily stores.	Often progresses slowly over months or years.
Primary Symptoms	Fatigue, weakness, anemia, oral sores, GI issues, irritability.	Similar to folate, plus distinct neurological symptoms.
Distinguishing Factor	Typically presents with megaloblastic anemia without neurological symptoms in adults.	Can cause severe neurological issues, including numbness, tingling, and nerve damage, which can become permanent if untreated.
Masking Risk	Can mask the symptoms of a co-existing B12 deficiency if treated with folic acid alone.	Treatment requires B12 supplementation and is not masked by folate intake.

Conclusion

While a folate deficiency is often reversible with treatment, the potential health consequences—ranging from chronic fatigue and anemia to severe birth defects and neurological damage—highlight the importance of prevention. Ensuring adequate intake through a diet rich in natural folate sources, fortified foods, and supplementation (especially for pregnant women or those planning to be) is key to protecting your health. If you experience any symptoms, consulting a healthcare provider for a proper diagnosis and treatment plan is essential, and remember to always address potential B12 deficiency alongside any folate treatment. For more on recommended intake levels, you can consult the National Institutes of Health (NIH) Fact Sheet on Folate.

Frequently Asked Questions

The initial signs often include persistent fatigue, weakness, pale skin, irritability, and a sore or red tongue. These symptoms are primarily caused by the resulting anemia.

Since the body does not store large amounts of folate, a deficiency can develop relatively quickly, within a few months of insufficient dietary intake.

Yes, psychological problems, including depression and anxiety, can be associated with folate deficiency. Adequate folate is necessary for the production of neurotransmitters.

Both vitamins are crucial for red blood cell production, and their deficiencies cause similar types of anemia. It is important to check B12 levels before treating with folate, as folic acid supplements can correct the anemia but hide an untreated B12 deficiency, allowing neurological damage to progress.

Excellent food sources include dark leafy greens (spinach, kale), legumes (beans, peas), eggs, citrus fruits, liver, and fortified grain products like cereals and bread.

Women who are pregnant or planning to become pregnant are advised to take a daily folic acid supplement of at least 400 mcg, in addition to eating folate-rich foods, to prevent neural tube defects.

Conditions like celiac disease, Crohn's disease, and hemolytic anemia can interfere with folate absorption or increase its use in the body.