The Science Behind… Vitamin B9, Folate & Folic Acid


It is well-known that balanced intake of vitamins and minerals is essential to a healthy diet, and multiple sources of these vitamins exist, to cater for all dietary needs. Despite this, education regarding vitamin requirements in pregnancy and in everyday life may not be as widespread as the medical world would prefer. As a result, the benefits of key molecules such as vitamin B9 (which can also be known as folate or folic acid) often remain a mystery to those who have not had the chance to obtain essential information regarding such nutrients. 

Vitamin B9 is an essential vitamin found in legumes, eggs, leafy green vegetables, and bananas. It plays a significant role in the body, as it ensures the methylation of molecules such as DNA [1] – without this occurring, regular metabolism and genetic processes cannot occur properly [2]. As a result, vitamin B9 is essential to the continued maintenance of the body’s metabolism, as well as in the creation of cells such as those in the blood (i.e., red, and white blood cells). A deficiency in vitamin B9 will lead to a condition known as megaloblastic anaemia, which is a serious condition that can lead to life-threatening symptoms, if not corrected rapidly.  


Are folate and folic acid the same thing? 

For clarification, vitamin B9 is also known as folate, or folic acid, depending on the source of the vitamin’s creation. As a general rule, folate is the name given to vitamin B9 that is naturally found in dietary sources, whereas folic acid is the name given to the man-made version of vitamin B9 that is added to foods and supplements to improve dietary health in specific groups of people. They are hence essentially the same functional molecule, with differing names. 


Folate and folic acid 

The main group of people likely to have heard about the importance of vitamin B9/folate/folic acid will be couples who have had discussions with their doctor about preconception and pregnancy. This is because folate/folic acid is a crucial nutrient during the entire pregnancy process, owing to the well-recognized role it plays in reducing the occurrence of neural tube defects in children [3-5]. The reason behind this effect is due to the influence vitamin B9 has over ensuring correct rapid cell division during neuronal development, as well as in DNA synthesis, methylation, and repair [2].  

Doctors hence recommend a daily intake (through supplements) of 400 µg of folic acid for pregnant women and couples in the preconception process. As such, couples should make it a priority to maintain appropriate levels of vitamin B9 throughout a pregnancy, in accordance with medical advice. 


Folate, folic acid, and brain development 

Folic acid supplementation has also been linked to a reduced risk of autism spectrum disorders (ASDs) which potentially originate in early pregnancy [6]. A prospective population-based study of 85,176 children showed that there was a 39% reduction in risk of autism in children of mothers that consumed appropriate levels of folic acid during pregnancy, when compared to children of mothers who did not consume appropriate levels of folic acid [6]. Conversely, the same study also found no association between maternal folic acid status and conditions such as Asperger’s syndrome, though statistical power was limited for such disorders [6]. 

Results have also been published that support folic acid supplementation in reducing the risk of severe language delay [7], and in oral cleft and fetal growth restriction [8]. In the latter study, it was also highlighted that a high dose of folic acid (4mg/d) had no additional benefits in fetal growth and oral cleft incidence to the regular dose of folic acid (400μg/d) [8], reinforcing the fact that following recommended daily intake guidelines and medical advice is always the best option in such matters. 

There may also be added benefits to an unborn baby through the maintenance of maternal vitamin B9 levels throughout a pregnancy, as seen in a 2019 study that examined the effect of folic acid supplementation in pregnancy on cognitive performance in children at a later time [9]. In the UK-led study, it was observed that children who obtained higher IQ and language scores had mothers who maintained appropriate folic acid supplementation throughout pregnancy [9]. 

Vitamin B9 also appears to influence clinical depression, as noted in multiple publications [10-12]. A consistent finding throughout research into clinical depression has been that patients appear to have lowered levels of vitamin B9 in their blood [10-12], though a conclusive link as to how this deficiency influences clinical depression is not yet available. Interestingly, vitamin B9 supplementation to correct the deficiency is often considered as a co-treatment to standard pharmaceuticals, as patients with vitamin B9 deficiency do not often respond well to these commonly prescribed medicines [11, 13]. As an aside, it is worth noting that vitamin B9 alone has not been conclusively linked to the reversal of clinical depression. 


Folate, folic acid, and cardiovascular health 

Maintaining balanced levels of vitamin B9 has been linked to a reduction in the risk of stroke and cardiovascular disease in general  [14, 15], suggesting that optimal folate or folic acid levels may play a part in protecting the vasculature. However, in the same instance, an imbalance leading to either low or high levels of vitamin B9 seems to instead lead to a greater risk of developing cardiovascular disease [15, 16], particularly in the case of patients with high blood pressure. As such, it is worth considering maintaining optimal concentrations of folate through consumption of the recommended daily intake, to avoid either too much or too little folate in the diet and the body, though such action should always be in accordance with advice from a medical professional. 


Folate, folic acid, and cancer 

The effects of folate levels in the blood and any correlation to changes in cancer risk have also been studied extensively [16-20]. In these studies, it has been observed that low folate in the blood may increase the risk of multiple types of cancers [18]; conversely, too high levels of folate in the blood may increase the risk of prostate cancer [18, 19] and colon cancer [16]. However, appropriate folate intake appears to be beneficial with respect to prevention of cancer development, in that consumption of optimal levels of folate may proportionally decrease the risk of breast cancer [17] and may also act as a preventative substance to combat skin cancer [20]. So, as noted previously, maintaining balanced levels of vitamin B9 by adhering to the recommended daily intake guidelines (and medical advice) appears to be the most practical way to gain all the benefits vitamin B9 has to offer. 



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