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The adverse effects of an excessive folic acid intake


Folate is a vital component of a healthy diet, being essential for numerous bodily functions. Deficiency of folate is common, with studies suggesting prevalence of deficiencyas high as 85.5% as was shown in women between the ages of 16 and 49, living in the UK. Causes of folate deficiency range from diet and lifestyle, to pathological and pharmacological processes. Because of the well-known role of folate in prevention of neural tube defects, numerous countries have implemented strategies to increase folate intake, with programs such as mandatory grain fortification. As a result, the intake of folate in these countries is often higher than the recommended dietary allowance for many groups of people. Although folate is believed to be non-toxic, the potential adverse effects of excessive intake of folic acid (synthetic form of folate) have not been highlighted well by authorities to people taking supplements; despite this, many studies have addressed this issue. However, the results of these studies provide discrepant results, leading to confusion as to whether mandatory folic acid fortification should be introduced in other countries. The purpose of this review was to provide a summary of evidence related to high folic acid ingestion and to look at the unwanted effects it may have on the certain groups within the general population.

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We thank Mrs Renata Gorska (The Nutristasis Unit, Viapath) for preparation of the figure. We also thank the reviewers for their helpful comments. All of the information in this review is of original research and has not been published or submitted for publication to other journals.

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Correspondence to K R Patel.

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Patel, K., Sobczyńska-Malefora, A. The adverse effects of an excessive folic acid intake. Eur J Clin Nutr 71, 159–163 (2017).

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