What foods are high in folate, and what are its benefits?

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Folate, or vitamin B9, occurs naturally in a variety of foods. Sometimes, manufacturers fortify foods with folate’s synthetic form — folic acid.

The richest naturally occurring sources of folate include:

• beef liver
• vegetables, especially Brussels sprouts, dark leafy greens, and asparagus
• fruits and fruit juices, especially oranges and orange juice
• beans, peas, and nuts, such as kidney beans, black-eyed peas, and peanuts

Foods that companies often fortify with folic acid include:

• fortified corn masa flour, which is used to make tortillas and tamales
• fortified cereals
• enriched bread flour, pasta, rice, and cornmeal

The body’s ability to absorb and use folate varies from one food to another and is difficult to measure. There are also many forms of folate, and some break down during cooking or processing.

Folate deficiency can cause a wide range of symptoms. These may include:

• muscle weakness
• problems with judgment, memory, and understanding
• fatigue
• paresthesia, or pins and needles
• a red, sore tongue
• ulcers in the mouth
• vision problems
• depression and confusion

Because folate deficiencies usually occur alongside other nutritional deficiencies, such as B12 or iron deficiency, people may also have symptoms of these other conditions.

Most people in the United States get enough folate, but some are more at risk of not getting enough. These include people with:

• alcohol use disorder
• a mutation in the MTHFR gene, which impairs the conversion of folate into its active form so the body can use it
• conditions that interfere with nutrient absorption, such as inflammatory bowel disease or celiac disease
• eating disorders

Folate deficiency is more common among females, affecting around 19% of female adolescents ages 14–19 years and 17% of female adults ages 19–30 years. The rate among non-Hispanic Black females is higher, at 23%.

At present, researchers are not sure why folate levels are lower among Black females, but some believe it is due to social determinants of health, such as the availability of fresh food or difficulty accessing healthcare.

Folate is a form of vitamin B9, and it occurs naturally in various foods. Folic acid is also a form of vitamin B9, but it does not occur naturally in food. Companies add folic acid to foods to make them more nutritious. Both types are nutritionally valuable, and most people have no trouble absorbing either form.

Companies use folic acid in foods because, unlike folate, it remains stable when exposed to heat and light. This makes it ideal for adding to foods people cook, such as bread.

According to the Centers for Disease Control and Prevention (CDC), folic acid is the only form of vitamin B9 that is proven to reduce the risk of neural tube defects in fetuses. For this reason, people who are pregnant or trying to conceive should take 400 micrograms (mcg) of folic acid per day.

Folic acid and the MTHFR gene

Some people have a polymorphism in the MTHFR gene. That means this gene contains a mutation that reduces how effectively the body converts folic acid or folate into its active form, methylfolate. The body needs to be able to do this in order to make full use of this nutrient.

MTHFR gene polymorphisms affect:

• 25% of Hispanic people
• 10% of white and Asian people
• 1% of African Americans

Despite having a reduced ability to convert folic acid and folate into their active form, people with these polymorphisms can still consume either nutrient safely. People who are pregnant and have an MTHFR gene polymorphism should still take the recommended amount of folic acid.

Some people with this genetic difference may find it beneficial to take supplements that contain methylfolate itself, so the body does not have to convert it. However, studies on how effective this is have been inconclusive.

The recommended daily allowance (RDA) of folate differs depending on age. The RDA for various ages are as follows:

• 0–6 months: 65 mcg
• 7–12 months: 80 mcg
• 1–3 years: 150 mcg
• 4–8 years: 200 mcg
• 9–13 years: 300 mcg
• 14 years and older: 400 mcg
• during pregnancy: 600 mcg
• during lactation: 500 mcg

Folate is necessary for many bodily functions. Its health benefits include:

Lower risk of neural tube defects

An adequate amount of folic acid is essential during pregnancy to help prevent neural tube defects. This issue occurs when the neural tube, which forms the early brain and spinal cord, does not close properly. This happens in early pregnancy and can result in conditions such as spina bifida or anencephaly.

Lower risk of stroke

According to the National Institutes of Health (NIH), researchers have found that folic acid supplements lower levels of the amino acid homocysteine. High levels of this amino acid are linked to a higher risk of cardiovascular disease and stroke.

While studies have not proven that folic acid reduces the risk of cardiovascular disease, several have found that higher intake is associated with a lower risk of stroke.

Possible reduced risk of cognitive decline

Homocysteine is also associated with a higher risk of dementia. While studies have not shown that taking folic acid reduces the risk of dementia in otherwise healthy people, those who are at risk of cognitive decline in older age may benefit from taking it. Evidence suggests that it may help preserve memory and executive function in at-risk groups.

Folate and cancer

Research on the link between folate and cancer has produced varied results. Some studies, such as one from 2017, suggest that folate may offer protection against certain cancers. Low folate levels are associated with an increased risk of certain cancers, such as lung, breast, cervical, and stomach cancers.

However, other studies have not found an association between the vitamin and cancer.

In moderate amounts, folate is not dangerous to most people. However, in large amounts, folate may pose certain health risks. Depending on the situation, this could include:

• Masking vitamin B12 deficiency: People with vitamin B12 deficiency may develop megaloblastic anemia, which can cause neurological damage if left untreated. As folate can help treat certain symptoms of anemia, but not the neurological damage it can cause, folate could mask symptoms until the consequences of the true deficiency become irreversible.
• Preneoplastic lesions: These lesions consist of altered cells that are more likely to become cancerous than regular cells. High folic acid intake has been linked to faster progression of these cells, which may increase the risk of certain cancers, such as colorectal cancer.
• Unmetabolized acid: If a person has more folic acid than the body can metabolize and transform, it could affect the immune system. Some scientists have also suggested there may be a link between unmetabolized folic acid and cognitive impairment in older adults. However, there is not much research on this, so the risk is unknown.
• Medication interaction: Folate supplements may interact badly with various medications, including epilepsy medications, methotrexate, and sulfasalazine.

Before taking any dietary supplement, it is important to speak with a doctor to check that it is safe and there are no other deficiencies or conditions that need to be addressed.

Folate is a naturally occurring form of vitamin B9, which people get from their food. Dark leafy greens, beef liver, and oranges are all good sources of folate. People can also get another form of B9, folic acid, from fortified foods. Some common examples include cereals, breads, and pasta.

Most people get enough folate from a balanced diet, but others may need extra help getting enough. A folate deficiency can cause fatigue, mouth ulcers, and a low mood. It is more common in females and those with conditions that affect folate absorption.

If someone is concerned they may have a nutritional deficiency or are trying to conceive, they should speak with a doctor.