You’re going to hear in the news how studies show that multivitamins do not really help anyone (such as this study).  You’re going to hear Dr. Paul Offit gloat about how he was correct – given this one study.  (He also has said that aluminum in good for a fetus, and that one could inject a baby with 100,000 – wait, no, 10,000 vaccines at once with no harm).

Then you’re going to hear that ONE supplement was found to be beneficial – folic acid.

But those news stories do not tell you that folic acid may contribute to health issues in a majority of people.

I’m preaching to the choir in the vaccine risk aware community about the differences between folic acid and folate.  They know that folic acid can reduce the incidence of spina bifida in pregnancies.  Those women who were deficient in folic acid in their diet decades ago and had children with spina bifida could have been helped via folic acid. Fair enough.

But here’s what happens when you take folic acid, and why you should take vitamins with folate instead:

(Image from Crider et al. 2012)
You can see from the pathway diagram that an excess of folic acid will provide negative feedback on processes that impact Methionine synthase & SAM-Mediated DNA methylation,  Thymidylate synthesis, DNA methylation and DNA synthesis.  That means that folic acid can be a limiting factor and have a negative effect (shut down) these critical genomic processes – especially for people with mutations in the MTHFR gene.
Understanding this is especially important for mutation carriers of the gene 5,10 MTHFR. But it’s likely important for all of us, as well, especially as we age.  As we get older, some of our genes (including MTHFR) acquire somatic mutations and begin to produce aberrant proteins in some of our cells.  Most of the time, the cells producing strange proteins are found by immune system and destroyed. But often, they are not.  And thus some of our cells are MTHFR-deficient.
Therefore, folate (tetrahydrofolate) is probably better for us than folic acid in the aging process as well.
Most nutrionist or biochemist would confirm that folate in the diet is probably superior than folic acid, or at least that they think there may be no significant difference in general. In fact, Crider et al. report that folate can be limiting in the pathway converting folic acid to folate – which it should, right, because that’s what we want, folate, not folic acid.  The more folate in your diet, the less likely the pathway is to convert folic acid, because it already had folate. That’s why many will likely just tell you that folate in vitamins is just more expensive than folic acid.
But folic acid also shuts down your cells ability to use the Folate you get from your diet (leafy greens, for example).  So you become increasingly dependent on folic acid, we rely less on dietary sources, were are short-circuiting the normal methylation processes.
Are folate supplements a “risk-free, magic bullet”?  No. Taking Folate in the 5-Methyl THF form (methylfolate) can have some side effects on mood.  Niacin (a B-vitamin) can relieve those side effects.  Thus, taking Folate along a source of Niacin is a better idea that taking methylfolate by itself.
Up to 60% of the population has a mutation in the MTHFR gene, making the folic acid route to folate impossible or difficult (depending on the type of mutation).  Which mutation you have matters.  We live in an increasingly toxic world in which we are subjected to ever increasing amounts and higher diversity of environmental toxins – in our food, water, air, shelter, clothing – and in our medicines. So we should give our genomes the best chance to function properly.
We should all do more to protect our brain, all of our cells from the potential damaging effects of folic acid by taking multivitamins with folate, not folic acid.
I’m going to try these pre-natal vitamins myself, from Garden of Life. I am told if there are side effects such as moodiness, I should take one every other day instead of once a day or trying tapering (building up to one a day).
For more information on side effects, visit Dr. Ben’s page MTHFR.net.
Crider et al. 2012. Folate and DNA Methylation: A Review of Molecular Mechanisms and the Evidence for Folate’s Role. Advances in Nutrition 3:21-38. doi: 10.3945/an.111.000992
Dr. Lyons-Weiler is the author of three book, the latest of which is “The Environmental and Genetic Causes of Autism”.  You can visit the book’s companion website to view over 1,000 studies cited in “Causes”, order the book online, or request it from your favorite local indie bookseller.


  1. Hi. I was just talking about this yesterday. I found out my triplets have problems absorbing folic acid and B vitamins (one has MTHFR and the other two have MTRR). The MTHFR kid is autistic, severely. The two with MTRR are showing some signs of spinal curvature (just found). They are going to be 16 in July. I now believe this has something to do with the type of vitamins I was taking when I was pregnant. The severity of things may have been much less if I’d been taking folates instead of folic acid. They could have absorbed this better. Just an observation I thought was worth mentioning. We can still heal this with supplementation and other methods, as their bones are most likely not fused yet. I think. I hope. Melissa Culhane >

  2. Before you take a supplement containing iron, it’s a good idea to check your ferritin levels (you want this under 80, even though the reference range is typically wider). For most men, increasing iron intake isn’t a good idea.

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