Folate, also known as vitamin B9, is an essential water-soluble vitamin naturally found in various foods and available as a dietary supplement. Understanding “What Is Folate Good For” is crucial because it plays a vital role in numerous bodily functions, including DNA synthesis and cell growth. This article provides a comprehensive overview of folate, its benefits, sources, and potential health implications.
Understanding Folate: Types and Functions
Folate encompasses several forms, including naturally occurring food folates and folic acid, a synthetic form used in supplements and fortified foods. Food folates are typically polyglutamates, while folic acid is the monoglutamate form. Some supplements also contain 5-MTHF (methylfolate), another monoglutamyl form.
Folate acts as a coenzyme in single-carbon transfers, which are critical for:
- DNA and RNA Synthesis: Folate is essential for building nucleic acids, the building blocks of our genetic material.
- Amino Acid Metabolism: Folate participates in the breakdown and utilization of amino acids, the building blocks of proteins.
- Homocysteine Conversion: Folate converts homocysteine to methionine, a crucial process for producing S-adenosyl-methionine, a significant methyl donor.
- Cell Division: Folate supports proper cell division through DNA methylation. Deficiency can lead to megaloblastic anemia.
Folate is naturally present in a wide variety of foods, including vegetables such as spinach.
Folate Absorption and Metabolism
When we consume food folates, they are broken down into the monoglutamate form in the gut before being absorbed. Folic acid, on the other hand, is absorbed through both active transport and passive diffusion. After absorption, the enzyme dihydrofolate reductase converts folate into its active forms, tetrahydrofolate (THF), methyl, or formyl forms. The main form of folate found in plasma is 5-MTHF.
It’s important to note that the activity of dihydrofolate reductase varies between individuals. When the enzyme’s capacity is exceeded, unmetabolized folic acid can be found in the blood. The biological activity and significance of unmetabolized folic acid are still under investigation.
Folate is also produced by the gut microbiota, but the extent to which it contributes to overall folate status remains unclear. The body’s total folate content is estimated to be 15 to 30 mg, with roughly half stored in the liver.
Assessing Folate Status
Healthcare professionals use several methods to assess folate status:
- Serum Folate Concentration: A level above 3 ng/mL is generally considered adequate. However, this indicator is sensitive to recent dietary intake.
- Erythrocyte Folate Concentration: A level above 140 ng/mL offers a longer-term measure of folate status.
- Plasma Homocysteine Concentration: Elevated homocysteine levels can indicate folate deficiency. However, homocysteine levels can be influenced by other factors, such as vitamin B12 deficiency and kidney dysfunction. A homocysteine cutoff of 10 micromol/L has been proposed for population assessments.
Recommended Dietary Intakes (RDAs)
The Food and Nutrition Board (FNB) has established Dietary Reference Intakes (DRIs) for folate, which include Recommended Dietary Allowances (RDAs) and Adequate Intakes (AIs). RDAs are expressed as mcg of dietary folate equivalents (DFEs) to account for the higher bioavailability of folic acid compared to food folate.
- 1 mcg DFE = 1 mcg food folate
- 1 mcg DFE = 0.6 mcg folic acid from fortified foods or supplements (taken with food)
- 1 mcg DFE = 0.5 mcg folic acid from supplements (taken on an empty stomach)
The RDAs for folate vary by age, sex, and life stage:
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| Birth to 6 months* | 65 mcg DFE* | 65 mcg DFE* | ||
| 7–12 months* | 80 mcg DFE* | 80 mcg DFE* | ||
| 1–3 years | 150 mcg DFE | 150 mcg DFE | ||
| 4–8 years | 200 mcg DFE | 200 mcg DFE | ||
| 9–13 years | 300 mcg DFE | 300 mcg DFE | ||
| 14–18 years | 400 mcg DFE | 400 mcg DFE | 600 mcg DFE | 500 mcg DFE |
| 19+ years | 400 mcg DFE | 400 mcg DFE | 600 mcg DFE | 500 mcg DFE |
*Adequate Intake (AI)
Sources of Folate
Folate can be obtained from various sources:
Food Sources
Folate is naturally abundant in many foods, including:
- Dark green leafy vegetables (e.g., spinach, kale)
- Fruits and fruit juices (e.g., oranges, strawberries)
- Nuts and beans
- Peas
- Seafood
- Eggs
- Dairy products
- Meat and poultry
Dark green leafy vegetables, fruits, nuts, beans, peas, seafood, eggs, dairy products, meat, and poultry all contain Folate.
Fortified Foods
Since 1998, the FDA has required manufacturers to add folic acid to enriched grains, such as breads, cereals, flours, and pastas, to reduce the risk of neural tube defects. This fortification program has significantly increased folic acid intakes in the United States.
Dietary Supplements
Folic acid is available in multivitamins, prenatal vitamins, B-complex vitamins, and stand-alone supplements. Doses range from 680 to 1,360 mcg DFE (400 to 800 mcg folic acid) in supplements for adults and 340 to 680 mcg DFE (200 to 400 mcg folic acid) in children’s multivitamins.
Folate Intakes and Status in the United States
Data from the National Health and Nutrition Examination Survey (NHANES) show that most people in the United States consume adequate amounts of folate. However, certain groups, such as women of childbearing age and non-Hispanic Black women, may be at risk of insufficient folate intakes.
Approximately 35% of adults and 28% of children in the United States use supplements containing folic acid. Measurements of erythrocyte folate levels also suggest that most people have adequate folate status.
Folate Deficiency: Risks and Symptoms
While isolated folate deficiency is uncommon, it can occur in conjunction with other nutrient deficiencies due to poor diet, alcoholism, or malabsorptive disorders. The primary clinical sign of folate deficiency is megaloblastic anemia, characterized by large, abnormally nucleated erythrocytes.
Symptoms of folate deficiency can include:
- Weakness and fatigue
- Difficulty concentrating
- Irritability
- Headache
- Heart palpitations
- Shortness of breath
- Soreness and ulcerations of the tongue and oral mucosa
- Changes in skin, hair, or fingernail pigmentation
- Gastrointestinal symptoms
- Elevated blood concentrations of homocysteine
Women with insufficient folate intakes are at increased risk of giving birth to infants with neural tube defects. Inadequate maternal folate status has also been associated with low infant birth weight, preterm delivery, and fetal growth retardation.
Groups at Risk of Folate Inadequacy
Several groups are at higher risk of folate inadequacy:
- People with Alcohol Use Disorder: Alcohol interferes with folate absorption, accelerates its breakdown, and increases its excretion.
- Women of Childbearing Age: Adequate folate intake is crucial to reduce the risk of neural tube defects.
- Pregnant Women: Folate needs increase during pregnancy to support nucleic acid synthesis.
- People with Malabsorptive Disorders: Conditions like celiac disease and inflammatory bowel disease can impair folate absorption.
- People with an MTHFR Polymorphism: Individuals with a genetic polymorphism in the MTHFR gene may have a reduced ability to convert folate to its active form, 5-MTHF.
Folate and Health: Exploring the Benefits
Now, let’s dive deeper into “what is folate good for” in the context of various health conditions:
Autism Spectrum Disorder
Emerging evidence suggests that periconceptional folic acid supplementation might reduce the risk of autism spectrum disorder (ASD) or mitigate the potentially increased risk of ASD from prenatal exposure to certain drugs and toxic chemicals.
Cancer
Epidemiological studies have suggested an inverse association between folate intakes and status and the risk of several cancers, including colorectal, lung, and pancreatic cancer. However, the precise nature of folate’s effect on carcinogenesis is still under investigation, and clinical trials have yielded mixed results. Some research even suggests that high doses of folic acid after preneoplastic lesions have been established might promote cancer development and progression.
Cardiovascular Disease and Stroke
While folic acid supplements lower homocysteine levels, they do not consistently decrease the risk of cardiovascular disease. However, some studies suggest they provide protection from stroke, particularly in populations without folic acid fortification.
Dementia, Cognitive Function, and Alzheimer’s Disease
Most clinical trial research has not shown that folic acid supplementation affects cognitive function or the development of dementia or Alzheimer’s disease. However, some studies have found that B-vitamin supplementation slowed cognitive decline in individuals at high risk.
Depression
Low folate status has been linked to depression and poor response to antidepressants in some studies. Supplementation with certain forms and doses of folate might be a helpful adjuvant treatment for depressive disorders, but more research is needed.
Neural Tube Defects
Adequate periconceptional folic acid consumption by women prevents a substantial proportion of neural tube defects. Since mandatory folic acid fortification began in the United States, NTD rates have declined.
Preterm Birth, Congenital Heart Defects, and Other Congenital Anomalies
Folic acid supplementation might increase mean gestational age and lower the risk of preterm birth. It may also help minimize the risk of congenital heart defects and other congenital anomalies.
Health Risks from Excessive Folate
While folate is essential, excessive intake can pose health risks. High intakes of folate supplements can mask vitamin B12 deficiency, potentially leading to irreversible neurological consequences. There are also concerns that high folic acid intakes might accelerate the progression of preneoplastic lesions, increasing the risk of colorectal and other cancers in certain individuals. The FNB has established Tolerable Upper Intake Levels (ULs) for synthetic forms of folate to minimize these risks.
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| Birth to 6 months | Not possible to establish* | Not possible to establish* | ||
| 7–12 months | Not possible to establish* | Not possible to establish* | ||
| 1–3 years | 300 mcg | 300 mcg | ||
| 4–8 years | 400 mcg | 400 mcg | ||
| 9–13 years | 600 mcg | 600 mcg | ||
| 14–18 years | 800 mcg | 800 mcg | 800 mcg | 800 mcg |
| 19+ years | 1,000 mcg | 1,000 mcg | 1,000 mcg | 1,000 mcg |
- Breast milk, formula, and food should be the only sources of folate for infants.
Interactions with Medications
Folate supplements can interact with several medications, including methotrexate, antiepileptic medications, and sulfasalazine. Individuals taking these medications should discuss their folate intakes with their healthcare providers.
Folate and Healthful Diets
A healthy dietary pattern, as described in the Dietary Guidelines for Americans, includes a variety of vegetables, fruits, grains (at least half whole grains), fat-free and low-fat milk, yogurt, and cheese, and oils. Many fruits and vegetables are good sources of folate. The diet should also include a variety of protein foods such as lean meats, poultry, eggs, seafood, beans, peas, and lentils, nuts and seeds, and soy products. Beef liver, peas, beans, nuts, and eggs also have folate.
Conclusion: Maximizing Folate’s Benefits
Understanding “what is folate good for” highlights its critical role in maintaining overall health. From supporting DNA synthesis and cell growth to potentially reducing the risk of certain diseases, folate offers numerous benefits. By consuming a balanced diet rich in folate-containing foods and, if necessary, considering supplementation under the guidance of a healthcare professional, you can ensure adequate folate levels and reap its many advantages.
