IS TONGUE TIE CAUSED BY FOLIC ACID?
I am frequently asked this question by families attending our Tongue Tie Centre and this is often followed by whether they can prevent tongue tie for a future child by taking a folate supplement instead of folic acid.
The bottom line is that there is no published study that compares folic acid to folate and the incidence of tongue tie, but to understand what may be best for you we need to look at why folic acid supplementation is recommended and what the difference is between folic acid and folate.
WHY IS TAKING FOLIC ACID RECOMMENDED BEFORE AND DURING PREGNANCY?
Studies from the 1970’s showed an association between maternal folate deficiency and an increased risk of spina bifida. The studies that followed in the 80’s and 90’s showed the reduction of this risk by supplementing with folic acid. These studies are why worldwide there is a recommendation to take folic acid before becoming pregnant and during early pregnancy. There been studies since which also suggest a reduction in other abnormalities including ventricular septal defect, gastroschisis and hypospadias.
SO WHY IS THERE FORTIFICATION OF FOOD IN SOME PARTS OF THE WORLD?
There is a protective effect against spina bifida that is related to maternal folate levels during early pregnancy. Spina bifida occurs because of failure of the neural tube to fuse which leaves an area of the spinal cord open. This occurs very early in pregnancy, in the first 4 to 6 weeks following the mother’s previous menstrual period. So by the time a mother realises that she is pregnant the child could already have spina bifida. Therefore, folate supplements are recommended prior to conception. However, given that the timing of about 50% of pregnancies are not planned, pre-conception folate is not going to be of benefit in these pregnancies. The other option is to improve the folate status of the whole population by supplementing foods that we commonly eat such as bread and cereal. This is reported to have reduced the rate of spina bifida by about half. Food fortification however does not replace the need for pre-conception folic acid as it is not possible to give the recommended amount of folic acid needed in pregnancy to the whole population.
WHAT IS THE DIFFERENCE BETWEEN FOLIC ACID AND FOLATE?
There is a lot of confusion about the differences between folic acid and folate, and indeed the terms are often used interchangeably. Folate tends to be used as the overarching term and natural folate refers to that derived from natural dietary sources, and folic acid the synthetic form. Folate is also known as Vitamin B9.
Folic acid is the form used for fortification of food and the most common version found in supplements. It is more tolerant of heat than the other forms of folate and so it can be added to food products that need to be cooked such as bread and breakfast cereals. Folic acid is very well absorbed and needs to be converted in the body by enzymes to the active form 5-methyltetrahydrofolate (5MTHF).
The folate that we get from our diet, such as in green leafy vegetables and pulses, also needs to be converted to 5MTHF. Typically we only absorb about 50% of the folate consumed. This is also not as temperature tolerant so large quantities of raw green leafy vegetables need to be consumed, or even larger quantities if they are cooked, to meet the demands during pregnancy hence the needs for supplements.
The final step in the conversion to 5MTHF is performed by the enzyme 5,10-methlylenetetrahydrofolate reductase (MTHFR). There is genetic variation in this enzyme, that is commonly seen both globally and in the Irish population, and this can affect how efficiently this enzyme works. There are many claims about the benefits of taking 5MTHF to avoid the enzyme steps. The studies show that red cell folate, which is marker of total body folate, can be increased by supplementation with 5MTHF or folic acid irrespective of MTHFR polymorphisms.
SO WHY DO WE NEED FOLATE?
Everyone needs folate as we cannot manufacture it, so it is an essential component of our diet. Folate is involved in making the building blocks of our DNA, methylation of compounds including DNA and in the process that removes homocysteine from the body; Vitamin B12 is also needed for this process. Elevated maternal homocysteine levels have been associated with spina bifida. Folate is used by cells which turnover quickly and this is why folate deficiency can be a cause of anaemia, especially in pregnancy.
SO WHAT IS THE LINK BETWEEN TONGUE TIE AND FOLIC ACID?
Tongue tie is often discussed as part of a group of conditions known as ‘midline defects’. This group includes spina bifida and cleft palate. The importance of folic acid and folate in spina bifida has been discussed above.
There are mice studies that show tongue abnormalities in the offspring of mice whose mothers had a folate deficient diet. One study from 2005 found reduced thickness of the tongue epithelium (surface layer) with folate deficiency. It has been postulated that a plentiful or high level of folic acid might produce increased thickness of the epithelium and if the same were to happen to the tongue frenulum it may be thicker or fail to ‘die back’ (apoptosis) as part of normal embryological development. Whilst this hypothesis may be correct, at the moment this is only a theory, we would need a study that explores the effect of levels of folic acid on the tongue frenulum to answer this question.
This theory is, in part, based on the fact that we are now seeing higher rates of tongue tie division and as folic acid supplementation is a significant population-based change that has happened within this timeline this may be the cause. One problem with this theory is that we do not have any data on the rate of tongue tie in the population prior to folic acid supplementation.
During the 1970’s and 80’s there was a move against the routine division of tongue tie in infants and eminent Paediatricians at the time spoke out against this practice. It is only since the start of this millennium that recognition and division of tongue tie in infants has been more common practice again. This change appears to follow increasing breastfeeding rates.
What we observe in our clinic is how many of the parents of infants with tongue tie have issues with sleep disordered breathing, sleep apnoea, underwent extraction retraction orthodontics, have jaw pain or speech difficulties. When examined they usually have a short, restricted tongue frenulum. Therefore, from my experience, I propose that tongue tie was prevalent during this period but frequently not recognised.
A study from Mexico, published in 2018, examined the mouths of newborn infants for intra-oral pathology on the first day of life. There was a good sample size (2216 infants) and 25% of the mothers had taken no folic acid supplementation. The rate of tongue tie was reported as 1.5% but no difference was found in the rate of tongue tie between the infants whose mothers had folic acid supplements and those who had not. The reported rate of tongue tie in this study is low compared to to other studies but they don't state what their definition of tongue tie is. The article is available here: https://www.e-cep.org/upload/pdf/kjp-2017-06177.pdf
In a study published in January 2020, a group from Israel compared 85 infants diagnosed with tongue tie to 140 infants without tongue tie and compared their mother’s consumption of folic acid. They found that there was a 3 fold increase in risk of tongue tie, which was statistically significant, for those whose mothers reported they took folic acid every day. There was an increase risk for those reporting they took folic acid ‘most days’ or ‘any intake’ but the difference was not statistically significant. This article is available here: https://www.sciencedirect.com/science/article/pii/S0306987719311259
These two studies have conflicting conclusions, although they have explored the question in different ways, further research is required to see if any difference is seen in larger studies. Fortification of flour occurs in both Mexico and Israel at a level of 150micrograms/100grams so the above comparisons are of periconception folic acid supplementation.
Currently, we have no data to determine whether there is any difference between folic acid or 5MTHF supplementation on the of risk of tongue tie.
The studies looking at folic acid and tongue tie discussed above offer opposing conclusions so further studies are needed to determine if peri-conception folate supplementation has an effect on the rate of tongue tie and also if there is any difference between folic acid and 5MTHF.
What we do know is that folic acid reduces the risk of spina bifida. The best effect is seen when food fortification and peri-conception supplementation are combined. My opinion is that folate supplementation should always be taken regardless of a previous history of tongue tie.