tac-dung-cua-vitamin-b9-550x624Vitamin B9, also referred to its other name as folate or folic acid, is a molecule linked to one of 8 B vitamins. Folic acid intake is especially important in youth and throughout life due to its potent health benefits. A new study focused to understand the effects of folic acid concentration in a diet, found that excessive levels of folic acid is linked to nerve damage in older adults. Indeed, unlike control patient, patient who contain a genetic variant of TCN2, the gene which encodes vitamin B12 transport protein, had high concentration of folic acid and experienced nerve damage.

Folic acid is a common water soluble vitamin which is widely available as a dietary supplement. It is found in many natural foods, and sufficient intake to function properly only requires 4 milligrams per day.  Folic acid has many important properties i.e. before and during pregnancy folic acid can help prevent birth defects of baby's brain and spinal cord. Moreover, studies have shown that folic acid is also important to prevent different forms of cancers. Folic acid is known to work in conjunction with other B vitamins in order to lower homocysteine levels, which is a cause for other diseases. Deficiency in folic acid isn’t a common occurrence in developed areas. It is common in places that are still developing, where there are incidences of malnourishment.

Although folic acis is an exceptionally useful vitamin to take as part of a diet, a new study has shown this may not be ideal for all adults. According to the study by Tufts University, consumption of too much folic acid will lead to an increased risk of nerve damage in patients who suffer from a genetic variant of the gene TCN2, which is programmed for B12 protein transport. Typically, one out of six adults in the United States will suffer from this (not according for specific age or ethnical groups that are more likely to be exposed to this). The study included 171 adults aged 60 or over, and found that those who intake up to double the amount of required folic acid developed an increased rate of seven times more likely chance of nerve damage. The mechanism behind this is that increased intake of folic acid in terms of the gene variant act negatively in neurological deficits which is associated with B12 deficiency.

This data highlights the importance of proper vitamin intake, especially the correlation between folic acid and B12. Although the study found a correlation between excess folci acid and the risk of increased nerve damage in the presence of adults with TCN2 gene variant, the study does not highlight a correlation. Researchers believe that there is more happening in this occurrence, but still acknowledge the importance of folic acid rich diets and the importance of folic acid in nursing mothers, infants, and aging adults. 

COPYRIGHT: This article is property of We Speak Science, a non profit institution co-fonded by Dr. Detina Zalli (Harvard University) and Dr. Argita Zalli (Imperial College London). The article is written by Detina Zalli and Antonio Del Vecchio (Cornell University).


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  • Image adapted from: http://photos2.demandstudios.com/DM-Resize/photos.demandstudios.com/getty/article/103/6/477762134_XS.jpg?w=640&h=10000&crop_min=1&keep_ratio=1 
  • Image adapted from: http://foodandhealth.ru/wp-content/uploads/2015/12/vitamin-b9.jpg
  • https://www.sciencedaily.com/releases/2016/10/161012141654.htm
  • https://ods.od.nih.gov/factsheets/Folate-HealthProfessional/
  • http://www.cdc.gov/ncbddd/folicacid/recommendations.html
  • http://umm.edu/health/medical/altmed/supplement/vitamin-b9-folic-acid
  • https://www.ncbi.nlm.nih.gov/gene/6948