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Clinical research into folates and folic acid supplementation continues to highlight its vital role in safe pregnancy and infant health.

The benefits of folate supplementation during pregnancy have been well researched, with clinical trial evidence for its efficacy mounting over the years. The first inklings that deficiency in certain vitamins may affect pregnancy outcomes was in the 1960s, when Dr Richard Smithells and Dr Elizabeth Hibbard discovered that women who gave birth to children with serious birth defects — particularly neural tube defects (NTDs) — displayed abnormal formiminoglutamic acid excretion. 

Fast-forward to 1983, when the ‘MRC Vitamin Study’ trial was conducted to assess the effects of vitamin supplementation — or lack thereof — among a large group of pregnancies. The final results were not published until 1991 and showed that approximately 80 per cent of NTDs could be prevented by taking 4mg of folic acid before pregnancy. This laid the groundwork for subsequent, more refined and more informed clinical trials to elucidate the benefits of folate supplementation in pregnancy. In the modern public health sphere, ongoing research has also spawned debates around the potential need for mandatory fortification of flour with folic acid. 

As folate cannot be stored in the body, daily dietary intake or supplementation is required, according to the HSE. The Executive recommends that women need 400 micrograms of folate each day. However, women and teenagers who may become pregnant within the next year need an extra 400 micrograms of folic acid as a supplement every day. This should be combined with a healthy diet and lifestyle. 


Research shows that approximately 50 per cent of pregnancies are unplanned, therefore it is recommended that all women who could become pregnant should take a daily supplement, whether or not they intend to become pregnant. The HSE also notes that women do not get sufficient folates from their diet, therefore a daily folic acid supplement is also recommended. 

Safefood further recommends that people with a chronic medical condition such as diabetes, or those who are overweight or have a history of NTDs in their family or their partners, may need to take a higher dose and should seek the advice of a healthcare professional in this regard. Wholegrains, green leafy vegetables, peas, and lentils, for example, provide nutrition with folic acid, and it is recommended that all adults require 200 micrograms of folic acid each day. However, it is not possible for women of childbearing age to get an extra 400 micrograms from their diet, so they require a supplement. Safefood notes that currently, one-third of women are not getting enough folic acid to protect their babies against NTDs. 

Since the days of the early research, it has become clear that our bodies require folate to make DNA and other important genetic material. Folate is also required to help the body’s cells to divide and is especially important in unborn babies, as it helps their nervous system to develop. In the very first weeks of pregnancy, the neural tube closes and fuses, which is one of the reasons supplementation prior to conception is necessary — the neural tube later becomes the baby’s brain and spinal cord. 


As research into folic acid evolves and becomes more nuanced, studies have been published to highlight the benefits of folic acid in other areas of human health. A 2020 study by the Irish Longitudinal Study on Ageing (TILDA) researchers at Trinity College Dublin suggests that having higher folate levels seems to be associated with better cognitive function in older adults. Among the top-line findings was that cognitive performance was not worse in older people with low vitamin B12 combined with who have high folate levels. Study participants with normal vitamin B12 levels and high folate levels performed better cognitively than the others in the trial, but the use of folic acid-containing supplements was uncommon. There were higher rates among women than men, but less than 4 per cent overall were taking supplements. 

New research published this year has investigated the independent and collective effects of maternal folic acid supplementation or dietary folate intake on the risk of low birth-weight (LBW). “Our study results indicated that folic acid supplementation was associated with a reduced risk of LBW, and there was no interaction between folic acid supplements and dietary folate intake on LBW,” wrote the authors. 

As research into folic acid intake continues to expand and evolve to assess its relevance to the wider population, the years ahead will shed more light on the importance of this supplement and enhance knowledge around its benefits and applications.