A growing body of evidence links consumption of synthetic folic acid to a range of health problems, including tongue tie.  My first son was born with a severe posterior tongue tie that was not diagnosed at birth.  He suffered terrible feeding problems and needed tube feeding for 12 months and he had to have 5 surgical procedures.  He was so hungry he barely slept for years and he would scream for hours day and night.  An estimated 20 to 40% of the population have a mutation of the MTHFR gene, which means that they do not produce enough of the enzyme needed to convert synthetic folic acid into its natural form - folate.  The folic acid, that their body can't convert, prevents their body from absorbing enough folate.  This can lead to a range of birth defects, of which tongue tie is the most common.