Folic acid (vitamin B9): benefits, uses and why it's so important during pregnancy

Folic acid (vitamin B9) is one of those vitamins that dissolves in the body as soon as it's absorbed. The body doesn't build up its own reserves of folic acid – which is precisely why it's so important to obtain it through your diet and, at times, through supplements.

But what does this have to do with pregnancy, and how does it help your baby? And if it's so beneficial, when and why might it have adverse effects? In this article you'll discover how a folic acid deficiency develops, what the consequences are, and why taking folic acid during pregnancy is recommended.

What is folic acid

Nature provides plenty of foods containing B vitamins. The sources range from plant-based foods (broccoli, spinach, kale, citrus fruits) to animal-based ones (eggs, liver and so on). This natural form of vitamin B9 is known as folate.

Because the body sometimes doesn't take in enough vitamin B9 through diet alone, it needs support from supplements. Vitamin B9 is also added to foods such as flour, breakfast cereals and bread. So we also need a synthetic form of this B vitamin – and that form is called folic acid.

Folic acid is the synthetic form of the water-soluble vitamin B9, found only in supplements. It's an essential nutrient for your body, contributing to optimal bodily function and helping to prevent complications caused by a folic acid deficiency.

 The role of folic acid

One of folic acid's principal jobs is to help build and repair DNA and RNA within the body – particularly when cells and tissues are growing rapidly. That's why it is recommended above all for babies, adolescents and during pregnancy.

Together with vitamin B12, folic acid supports the formation of red blood cells and the optimal use of iron, helping to prevent anaemia. Other important functions include:

• Energy production
• Formation of certain types of protein
• Carbohydrate metabolism
• Growth, division and optimal function of cells
• Regulating the function of the nervous system
• Preventing certain birth defects in the foetus

Conversely, low folic acid levels can lead to a range of health problems, including anaemia, an increased risk of heart disease and disruptions to foetal development during pregnancy. This is exactly why folic acid supplementation is so important for pregnant women.

Folic acid – the key benefits

Folic acid is frequently recommended in supplement form to support various bodily functions.

These preparations contain both synthetic folic acid and folate (naturally occurring folic acid). Although both are forms of vitamin B9, the body metabolises them differently and they may therefore produce different beneficial effects.

If you're wondering what folic acid is good for, here are the most important benefits.

Folic acid helps prevent birth defects and pregnancy complications

Folic acid is recommended during pregnancy to support the normal, complication-free development of the foetus, and also to avoid health risks for the mother. Folic acid supplementation during pregnancy can help prevent:

• Congenital foetal abnormalities: in particular neural tube defects such as spina bifida (where the baby's brain, meninges or spine fail to develop fully) and anencephaly (where the baby's skull and bones don't form completely before birth).
• Complications during pregnancy: such as pre-eclampsia (high blood pressure and excessive protein in the urine after the 20th week of pregnancy).

 Treating folate deficiency

A shortage of folic acid in the body – in other words, folate deficiency – can have numerous adverse consequences. Anaemia, declining mental performance, a weakened immune system, depression and disruptions to foetal development during pregnancy are among the most common.

Taking folic acid can regulate folate levels in the body, restore balance and prevent complications.

 Folic acid keeps the brain healthy

Since folate deficiency is linked with a higher risk of dementia and impaired mental performance, folic acid supplements can support brain health. Statistics show that an optimal folate intake may even offer protection against Alzheimer's disease.

Folic acid helps in the treatment of mental health disorders

Folate deficiency has also been associated with schizophrenia, depression and other mental health disorders, as it impairs the production of neurotransmitters. Recent studies suggest that taking folic acid can ease the symptoms of conditions such as:

• Bipolar disorder
• Schizophrenia, including in combination with antipsychotics
• Postnatal depression,  including in combination with antidepressants

 Folic acid lowers risk factors for heart disease

One of folic acid's well-known benefits is that it lowers blood levels of homocysteine – an amino acid which in turn raises the risk of heart disease. Low folic acid levels frequently go hand in hand with elevated homocysteine levels.

By metabolising this amino acid and improving the function of resistance vessels, folic acid supports heart health. According to studies, it reduces the risk of stroke by 10% and the risk of other cardiovascular conditions by 4%.

 Folic acid may help keep blood sugar at an optimal level

In people with diabetes, folate and folic acid supplements can help balance blood sugar levels and reduce insulin resistance. Women with diabetes are advised to take a higher dose of 5 mg of folic acid (on prescription) from before conception until week 12 - speak to your GP.

Folic acid supplements reduce inflammation

There are numerous theories suggesting that folic acid reduces inflammation – some of which have been confirmed by studies. Vitamin B9 supplements can lower inflammatory markers such as CRP (C-reactive protein) in women with PCOS (polycystic ovary syndrome).

Folic acid helps reduce medication side effects

Methotrexate, for example, is a medicine that suppresses immune system activity in order to treat conditions such as psoriasis or rheumatoid arthritis. Because folic acid supports key bodily functions, it can soften the side effects of such medicines.

Folic acid helps reduce renal insufficiency

Homocysteine can accumulate when the kidneys aren't working optimally and fail to filter the blood sufficiently. This is precisely why around 85% of people with chronic kidney failure have raised blood homocysteine levels.

In these individuals, folic acid can help lower homocysteine and prevent heart disease.

Causes of folic acid (vitamin B9) deficiency

A folic acid deficiency can have various causes. This B vitamin is water-soluble and dissolves in the body, so no reserves are stored. Folate and folic acid must therefore be supplied to and absorbed by the body continuously – through a balanced diet and sensible supplementation.

The absence of such a balanced diet is one of the main causes of vitamin B9 deficiency, alongside factors such as:

Too low an intake of folate-rich foods

Pregnancy and breastfeeding

Dialysis

Haemolytic anaemia

Achlorhydria (absence of stomach acid) or hypochlorhydria (insufficient stomach acidity)

Surgery or conditions that impair the body's ability to absorb folate (e.g. gastric bypass surgery or coeliac disease)

Medicines that reduce folate absorption (e.g. methotrexate or sulfasalazine)

Excessive alcohol consumption

Symptoms of folic acid deficiency

When there isn't enough folate in the body, a deficiency develops that can cause megaloblastic anaemia – in other words, a shortage of red blood cells. This is the main symptom of the deficiency and shows itself through complaints such as:

• Fatigue
• Difficulty concentrating
• Headaches
• Weakness and breathlessness
• Weight loss
• Irritability
• Palpitations
• Pain inside the mouth and on the tongue
• Changes in skin, nail and hair colour
• Low mood
• The onset of certain allergies
• Memory loss

How to take folic acid (vitamin B9) – the recommended dosages

Although a balanced, folate-rich diet is important, it has been confirmed that the body absorbs folic acid better from supplements and from foods fortified with vitamin B9. Both sources therefore matter, and the recommended total intake is:

65 mcg: for babies aged 0 to 6 months

80 mcg: for babies aged 7 to 12 months

150 mcg: for children aged 1 to 3 years

200 mcg: for children aged 4 to 8 years

300 mcg: for children and adolescents aged 9 to 13 years

400 mcg: for adolescents aged 14 to 18 years

400 mcg: for adults aged 19 and over

400–800 mcg: during pregnancy

500 mcg: while breastfeeding

In theory, studies confirm that a folic acid dose of no more than 1 mg a day is generally safe for healthy people. In practice, however, it's always wise to follow your doctor's advice – all the more so for babies, children, during pregnancy and in the postnatal period.

Adverse effects can occur if the dose of 1 mg per day is exceeded. Some studies suggest that excessively high folic acid doses taken over a prolonged period, for example 0.8–1.2 mg a day, may increase the risk of cancer or heart attack in people with heart problems. Folic acid can also interact with various medicines. Always seek advice from a specialist before taking such supplements.

The importance of folic acid in pregnancy

During foetal development, the spine is one of the first parts of the body to form from the embryo. The baby's brain develops next. Too little folic acid in the mother's body can impair the development of the spine and the neural tube (brain and spine) – which is why supplementation is so important.

Folic acid also plays an important role during pregnancy in preventing premature birth and heart defects, and contributes to the normal development of the foetus. If you'd like to read more about how your baby naturally develops in each trimester of pregnancy: HERE you'll find everything you need to know.

How long should folic acid be taken during pregnancy

• general guidance

As a rule, folic acid supplementation is particularly important in the first trimester of pregnancy, and the NHS recommends a daily dose of 400 micrograms before conception and up to week 12 (5 mg on prescription if you are at higher risk)

You can start taking folic acid even before you become pregnant and continue taking it while breastfeeding at around 500 mcg a day.

This amount varies from woman to woman, however, and must be tailored to each individual's state of health. Always stick to the dosage your doctor recommends.

Foods containing folic acid

There are fortified sources such as bread, pasta, flour, breakfast cereals, biscuits and baked goods enriched with vitamin B12. In addition, foods that naturally contain folate include:

• Asparagus and artichokes
• Green beans and kidney beans
• Spinach, kale and lettuce
• Brussels sprouts
• Broccoli and cauliflower
• Peas
• Artichoke
• Avocado
• Peanuts
• Sunflower seeds
• Oranges
• Grapefruit
• Papaya
• Bananas
• Honeydew melon
• Eggs
• Beef liver

 Excess folic acid – the signs

It isn't only a folic acid deficiency that has adverse consequences; an excess does too. Taking too much folic acid can cause unmetabolised folic acid to build up in the blood, triggering a range of side effects. Such an excess shows itself through:

Weakening of the immune system

Disruption of brain function

Abdominal cramps

Diarrhoea, nausea and other digestive complaints

Sleep disturbances

Confusion and irritability

Epilepsy

Taking excessive amounts of folic acid during pregnancy can also adversely affect the foetus's brain development and increase the risk of autism.

The good news is that because vitamin B9 is water-soluble (it dissolves in water), it is easily excreted from the body in the urine. Having too much folic acid in the blood is therefore relatively rare.

Side effects and contraindications of taking folic acid

One common side effect of taking folic acid is that it can mask another deficiency – in the case of anaemia, for example. You might believe the folic acid is helping you, when in reality the anaemia has a different cause, such as an iron or B12 deficiency.

Where there's a B12 deficiency, a lack of correct treatment can lead to complications such as nerve damage. It's therefore very important to see a doctor and have blood tests carried out to establish precisely whether or not you need folic acid and other supplements.

Be careful, too, to take vitamin B9 only on your doctor's recommendation and to avoid an excess, in order to prevent the complications described above and possible interactions with other medicines.

Folic acid vs folate – what's the difference?

The essential difference lies in the type of vitamin: synthetic versus natural. Although folate and folic acid are often used interchangeably and are forms of the same vitamin (B9), they have different origins.

Folate refers to all forms of vitamin B9, including folic acid and 5-MTHF, a folic acid derivative. Folate is also the term for the natural form of vitamin B9 as found in foods such as liver, green vegetables or citrus fruits.

Folic acid is the synthetic form of folate – with a different structure and slightly different effects on the body. It's the form of vitamin B9 added to fortified foods, multivitamin preparations and other supplements.

Frequently asked questions about folic acid

 When should you take folic acid – morning or evening?

You can take folic acid at any time of day, whether morning or evening. What matters isn't the time of day but the timing in relation to meals. Vitamin B9 is water-soluble, so it's best taken with a glass of water immediately before a meal – for complete, optimal absorption.

How many folic acid tablets should you take per day?

The recommended folic acid dose depends on many factors, such as age, state of health, or whether the patient is pregnant or breastfeeding. The number of tablets recommended also depends on how much folic acid each one contains. Always take folic acid exactly as your doctor advises – in terms of both dose and duration.