unmetabolized folic acid

Folic acid, good or bad?

I came across this fantastic article from Dr. Ben Lynch about the side effects of folic acid recently. It's a must read so check it out.

Back in 2015, I wrote an article on this subject, and I'm reposting it here because it's really a fascinating topic. You can check out the original version on my old website and blog (pre Jennifer Caryn Brand Nutrition). Feel free to poke around on there too, I've got some recipes and other fun information!

Here's that article...

Is it true? Is folic acid detrimental to your health?

Folate (the form found in foods like broccoli, asparagus, lentils, and spinach for example) and folic acid (the form found in supplements and fortified in foods) is a B vitamin that is essential for brain function and development, and a number of other biochemical processes.

This vitamin is recommended especially for women of childbearing age and for pregnant women because a deficiency of it can result in neural tube defects (like spina bifida) in the unborn child.

Interestingly however, due to folic acid supplements and food fortification with folic acid there are large populations in the United States and around the world that have unprecedented high intake of the vitamin.

What has happened is that because of the importance of this vitamin for the prevention of congenital abnormalities, it has been added to foods it’s not naturally found in (this is fortification) for decades, and it's believed the practice has reduced the incidence of these congenital abnormalities. Researchers however have begun to look at unmetabolized folic acid in the plasma as a marker of excess folic acid intake. It is believed that unmetabolized folic acid in the plasma can have adverse effects on immune function and on overall health status. The fortification of foods with folic acid can result in an increase in unmetabolized folic acid concentration in those not even taking supplements of the vitamin [1, 2, 3].

There appears to be a connection between unmetabolized folic acid and cancer. It’s noted that a decrease in and avoidance of excess folic acid should be considered for those with a history of conditions that are risk factors for cancer. Such examples include diseases of the colon, prostate, intestines, and those with a history of cancer and/or are undergoing cancer treatment. Older folks that have high folate status and unmetabolized folic acid are at increased risk for cancer [1, 4].

There is a direct correlation between folic acid intake and unmetabolized folic acid and it is suggested that there is a level at which the enzyme DHFR (dihydrofolate reductase, which converts folic acid into its active form so the body can use it) becomes saturated (so it wouldn’t be able to continue this conversion and therefore can result in an increased concentration of unmetabolized folic acid). Other factors that affect the conversion of folic acid and its presence in the blood include age, pH in the intestines (which absolutely has to be very acidic in order to digest and absorb nutrients so your body can use them, and to prevent disease and illness), alcohol consumption, dose and duration of supplementation of the vitamin, and mutations in enzymes needed for folate metabolism [5].

Studies on this topic are mixed. Some suggest adverse effects on health due to excess folic acid intake resulting in increased concentrations of unmetabolized folic acid, and other studies note there is not enough evidence to demonstrate these adverse effects.

What’s the moral of the story? When it comes to supplements, they should never be taken willy-nilly. We are constantly bombarded by the media promoting health benefits of an infinite variety of supplements, and we frequently run out to purchase the latest panacea at the drop of a hat. So hold the phone folks! Talk to your doctor or your nutritionist before you start taking anything (and if you are already taking something, talk to your doctor or nutritionist before you stop, especially if it was something prescribed to you).

The best and safest way to get important nutrients in is through your diet. Eat whole real foods that naturally contain the vitamins (including folate) and minerals your body needs to function optimally. 

Interested in learning more? There are a variety of ways to connect with me.

For general questions >>>> click here <<<<

To schedule a strategy session to work with me >>>> click here <<<<

If you aren't sure if you're ready to dig in and commit to working with me, you can >>>> click here <<<< to schedule a pick my brain session.

If you want to create a custom diet plan (and one rich in natural folate containing foods to avoid possible complications of unmetabolized folic acid) >>>> click here <<<<


  1. Bailey, RL.; Mills, JL.; Yetley, EA.; Gahche, JJ.; Pfeiffer, CM.; Dwyer, JT.; Dodd, KW.; Sempos, CT.; Betz, JM.; Picciano, MF. (2010). Unmetabolized serum folic acid and its relation to folic acid intake from diet and supplements in a nationally representative sample of adults aged ‡60 y in the United States1–4. American Journal of Clinical Nutrition. 92:338-9.
  2. http://www.ncbi.nlm.nih.gov/pubmed/16365081
  3. http://www.fasebj.org/cgi/content/meeting_abstract/21/5/A104-d
  4. http://scholarworks.gsu.edu/cgi/viewcontent.cgi?article=1044&context=nutrition_theses
  5. http://www.ncbi.nlm.nih.gov/pubmed/22746304


 "Your nutritional needs are as unique as your fingerprint, and they are dictated by your individual biochemistry. As a functional and clinical nutritionist, I can help you interpret your body's nutrient needs and customize a plan to reach your health and wellness goals. This is personalized nutrition."
-Jennifer Caryn Brand, MPH, MS, CNS, Functional and Clinical Nutritionist

Wishing you a delicious weekend!

Functional and Clinical Nutritionist

Copyright © 2018 Jennifer Caryn Brand Nutrition, All rights reserved. 

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