Search icon


23rd Jul 2015

Why standard supplements may not meet your folic acid needs

Folic acid is vital for a healthy pregnancy, but are you taking the right type?

In recent years there has been an increase in the numbers of babies born with neural tube defects. As a result, doctors have been reissuing their advice that all women of child-bearing age should supplement with folic acid, even where conception is not being planned.

I wholeheartedly support this advice, but for a percentage of women, the standard folic acid supplements may not offer enough protection.

A few months ago I had an interesting discussion with a new couple I was consulting with. The woman was very concerned about her fertility potential and specifically, the risk of birth defects to any potential offspring because there was a history of birth defects in her family. Her cousin had a baby with cleft palate and her aunt had a baby with Down’s Syndrome. However, it was the information she shared about her sister that was especially interesting.

“My sister has had two babies with spina bifida. On the first baby, she had been taking the recommended daily dose of folic acid so the consultant told her that she would need to take 5mg, instead of the usual 400 micrograms per day in the lead up to the conception of her second baby. Yet, in spite of this, she still had another baby with spina bifida. How is that even possible? I thought folic acid was supposed to prevent that from happening.”

I explained to my patient that it was possible that her sister (and indeed, her other family members) had a problem with converting the standard form of folic acid into the bio-available form for use within the body. In these cases, high dose folic acid is not very helpful because the body can’t convert the folic acid for proper use within the body.

MTHFR- the little known enzyme with a big impact on fertility

Some women who have difficulty conceiving or repeated miscarriages may be familiar with this genetic variant. The form of MTHFR that appears to have the biggest impact on the conversion of folic acid into methylfolate is the c677t polymorphism.

If a woman tests positive for 1 copy (heterozygous) of this genotype, she would have about a 30% reduction in her capacity to properly metabolise folic acid. If she is unlucky enough to have two copies of the c677t variant, her ability is reduced by up to 70%.

What this means is that for a woman with a single copy (or worse again two copies) of c677t, supplementing with standard folic acid will not offer proper protection from neural tube defects.

Folic acid vs Methylfolate

The type of folic acid that we get in most supplements is not the same as the dietary folate you get when you eat leafy green vegetables. That said, it is not advisable to depend solely on green leafy vegetables for your folate needs, especially when you are trying to conceive, because there is no way of knowing how much you are getting. If your digestion is poor, you may not be absorbing it properly from your food.

The best supplement to take is one that contains L-Methylfolate (aka 5-MTHF or (6S)-5-MTHF) because this is the form of folate that is metabolically active and may be used instantly by the body. Research has also shown that supplementing with this form of folate was more effective at increasing red blood cell concentrations of this vital nutrient.

Even better again would be to take a supplement that also contains the bio-available form of B12 (look for methylcobalamin on the supplement label) because B12 works closely with Folate within the body.

If you suspect that genetic issues may have a part to play in your own fertility issues then be sure to mention it to your attending consultant. It could make all the difference to your chances of maintaining a healthy pregnancy.