If you're planning to fall pregnant or are already pregnant, chances are your doctor or gynaecologist would have emphasised the importance of folic acid supplementation.
Folic acid is a synthetic form of vitamin B9, commonly known as folate. It aids in the prevention of foetal neural tube defects (NTDs) in pregnancy.
NTDs are birth defects that involve the brain and spinal cord, resulting in conditions like spina bifida, wherein a baby's spine and spinal cord fail to develop properly, leading to lifelong complications and difficulties. NTDs may also cause anencephaly, a birth defect wherein a baby is born without parts of the brain and skull and usually dies within a few hours or days of birth. These types of birth defects are believed to occur in approximately 260,000 pregnancies a year worldwide, resulting in the termination of 50% of these1.
The mere thought of these types of defects is enough to make any informed woman who is contemplating pregnancy reach for folic acid supplements. However, not everyone is well-informed about the importance of this vitamin in a baby's early development, especially within the first month of gestation. In addition, many pregnancies are unplanned, often leaving little time for adequate supplementation, especially since most women only discover they're pregnant after the first month.
As such, in March of 1996, the US government ordered all food manufacturers to fortify grain products with 140 micrograms of folic acid per 100 grams of food. The compliance deadline was set for January 1998. The implementation of this plan effectively doubled the blood folate levels of women in their childbearing years and lowered the number of babies born with neural tube defects2. A total of 81 countries across the globe currently require the manufacturers of grain products to fortify these with folic acid.
A recent study whose results were published in JAMA Psychiatry this week aimed to investigate whether the increased foetal folic acid exposure as a result of food fortification was associated with any clinically significant changes in postnatal brain development. Their findings are the first ever to reveal that gestational exposure to folic acid improves brain health throughout childhood and show these effects.
A closer look at the study
The retrospective, observational clinical cohort study, entitled 'Association of Prenatal Exposure to Population-Wide Folic Acid Fortification With Altered Cerebral Cortex Maturation in Youths3', was conducted by researchers from Massachusetts General Hospital in Charlestown, USA.
It examined 292 youths aged between eight and 18 years of age who were born between January 1993 and December 2001, to determine the associations between folic acid exposure in the womb and development of the brain's cortex as well as the risk of developing mental illness in adolescence (as this phase of development occurs directly before the period of greatest risk in the development of mental health disorders).
By including participants born within these date ranges, researchers ensured that their sample of subjects were born prior to the formulation of a mandatory folic acid food fortification policy, as well as during and after the implementation of this mandate, which was essential for comparative purposes. Participants were grouped accordingly into non, partial and full exposure groups.
Participants underwent Magnetic Resonance Imaging scans (MRIs) between January 2005 and March 2015. Researchers also studied the data obtained from two other independent cohort studies which took place before and after folic acid food fortification was implemented in order to compare and assess their results for clinical accuracy.
The results showed differences in the thickness of the cerebral cortices of the various participants which correlated with their level of folic acid exposure in the womb. Those born after the full implementation of folic acid food fortification exhibited a thicker cerebral cortex and delayed thinning of this structure over time.
The significance of cerebral cortex thickness
When it comes to human intellectual ability, brain structure and the thickness of the cerebral cortex (the thin, outer layer of nerve cell tissue that covers the brain) are thought to play a significant role4. Once the brain has developed, the cortex, which plays an integral role in cognitive functions including language, memory, perception and consciousness, begins to selectively thin.
The rate of change at which thinning of the cortex occurs is associated with a person's change in IQ5. Higher intelligence is generally associated with delayed thinning of the cortex, while rapid thinning has been linked to the development of psychiatric disorders like schizophrenia and autism.
The slower thinning of the brain in participants who were fully exposed to folic acid during pregnancy showed a lowered risk of developing psychosis (mental illness).
What these results mean for the greater public
One of the study's senior authors, Dr Joshua L. Roffman concluded that these results demonstrate that prenatal folic acid consumption may, in addition to aiding in the prevention of neural tube defects, provide added protection and have far reaching effects on a child's overall brain health.
He added that even if the benefit of folic acid proves to be limited, due to the fact that this supplementation is safe for both a mother and her developing baby, affordable and accessible, these findings may promote wider use.
How much folic acid should you be consuming?
It is generally recommended that women in their childbearing years consume 400 micrograms (0.4mg) of folic acid per day, whether through fortified food or supplements in order to lower the risk of a foetus developing a neural tube defect in pregnancy6. Consuming amounts in excess of this does not necessarily further lower the risk of NTDs. A medical professional may, after a consultation recommend higher dosages.
If you choose to get the daily folic acid requirement from the food you eat, it is important to obtain folate from a variety of sources to ensure that adequate quantities are ingested. Supplementation in pill form is often a preferred choice as one can be confident that adequate amounts are being ingested.
References
1. US National Library of Medicine National Institutes of Health. February 2018. Estimates of global and regional prevalence of neural tube defects for 2015: a systematic analysis. Available: https://www.ncbi.nlm.nih.gov/pubmed/29363759 [Accessed: 06.07.2018]
2. US National Library of Medicine National Institutes of Health. October 2005. Changes in the birth prevalence of selected birth defects after grain fortification with folic acid in the United States: findings from a multi-state population-based study. Available: https://www.ncbi.nlm.nih.gov/pubmed/16240378 [Accessed 06.07.2018
3. The Journal of the American Medical Association Psychiatry. July 2018. Association of Prenatal Exposure to Population-Wide Folic Acid Fortification With Altered Cerebral Cortex Maturation in Youths. Available: https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2686139 [Accessed 06.07.2018]
4. ResearchGate. September 2013. Associations between cortical thickness and general intelligence in children, adolescents and young adults. Available: https://www.researchgate.net/publication/261761997_Associations_between_cortical_thickness_and_general_intelligence_in_children_adolescents_and_young_adults
[Accessed 06.07.2018]
5. McGill University. March 2014. New evidence confirms link between IQ and brain cortex. Available: https://www.mcgill.ca/channels-contribute/channels/news/new-evidence-confirms-link-between-iq-and-brain-cortex-233830 [Accessed: 06.07.2018]
6. Centers for Disease Control and Prevention. May 2018. Key Findings: Are Women Getting Enough Folic Acid? Available: https://www.cdc.gov/ncbddd/folicacid/features/kf-women-enough-folic-acid.html [Accessed 06.07.2018]