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The Dangers of Artificial Folic Acid

By Dr. Marc Bubbs ND, MSc, CISSN, CSCS
November 23, 2016
Figure 1 – Conversion of dietary folate into methylene tetrahydrofolate3
Figure 1 – Conversion of dietary folate into methylene tetrahydrofolate3

(Recently Dr Cordain talked about the issues with folic acid and why it’s not the same as folate on The Paleo Diet podcast. We recommend listening to the entire episode to get the full science, but if you want a shorter explanation in clear lay terms including recommendations for your diet, then please read on!)

The advent of synthetic folic acid was considered a god-send for expecting moms. That’s why in 1998, the USDA started “fortifying” all wheat containing products like bread, pasta, wraps, and bagels to help prevent the neural tube defects seen in mother’s who had low levels of dietary folate in their body.

At that time (and likely still today,) the majority of the population consumed bread on a daily basis, making fortifying bread a great way to supplement the general population with folic acid. However, in nutrition the devil is in the details and synthetic folic acid is not the same thing as folate, the vitamin found naturally in food like some vegetables and organ meats.

While the intentions were good, the implications and potential adverse effects of this fortification project are quire profound.

Pregnancy and Folic Acid Supplementation
By Loren Cordain, Ph.D.

What Is Folic Acid and Why Does the U.S. Require Supplementation?

Folic acid is a man-made synthetic vitamin first produced in the late 1940s. Folic acid, which doesn’t exist naturally in food, is much more stable than folate, which means it won’t spoil when added to package and processed foods. And it was discovered that the body can convert folic acid to the active form of folate in the body called methylene tetrahydrofolate (MTHR).

Researchers decided the more stable folic acid was ideal to add to breads, cereals, bagels, wraps, cookies, etc. to ensure the general population (expecting mothers in particular) would have adequate levels of folate in their blood. There was evidence that fortifying wheat products would prevent neural tube defects like spina bifida and anencephaly.1 Folate also protects the heart by lowering pro-inflammatory homocysteine levels in the body, which has been associated with increased risk of heart disease.2

Figure 1 – Conversion of dietary folate into methylene tetrahydrofolate3
Figure 1 – Conversion of dietary folate into methylene tetrahydrofolate3

What’s The Problem With Folic Acid?

If we look at this synthetic vitamin from an evolutionary perspective, significant concerns arise about its health merits. Since early man first roamed the earth 250,000 years ago until 70 years ago, folic acid didn’t exist. The compound was first synthesized in 1947.

North Americans have gone from no exposure to this synthetic vitamin for hundreds of millions of years to chronic over-exposure of folic acid with their morning toast or cereal, sandwich at lunch, and pasta for dinner (not to mention multi-vitamins.) Could this be detrimental to our health? The research seems to say… yes.

The enzyme that converts folic acid to MTHF has limited capacity, meaning overconsumption of folic acid leads to spillover into the bloodstream. While previous research in the 1990s didn’t see any concerns with this excess, new research is unveiling potential major adverse effects.4,5,6

Excess Folic Acid & Disease

Expecting mothers with low blood folate levels should be consuming more dietary folate to meet their needs (or a supplement more closely related to the natural form of folate, known as 5-MTHF, rather than folic acid).7 Too much folic acid is harmful to the nervous system and recently at the 2016 International Meeting for Autism Research in Baltimore experts highlighted a small but increased risk of autism in mothers with high blood levels of folate due to excess supplementation or exposure.4

Further, too much folic acid supplementation (or processed foods like breads) may increase the risk of colorectal cancer and heart disease. In 2009, the Journal of the American Medical Association (JAMA) found that folic acid supplementation was associated with increased cancer outcomes and all-cause mortality in heart disease patients.5 This study is interesting because it was performed in Norway, where there is no mandatory fortification of folic acid in foods, unlike in the USA and Canada.

Dietary Sources of Folate

If you eat “real food”, the hallmark of a Paleo approach, it’s actually easy to achieve the recommended daily intake of 400mcg per day.8 Leafy greens are chock-full of natural occurring folate with spinach at the top of the list providing 130mcg per half cup. Romaine yields 65 mcg and mustard greens 50mcg. Cruciferous veggies like asparagus (90mcg per 4 spears), Brussels sprouts (78 mcg per ½ cup) and broccoli (52 mcg per ½ cup) are also high in natural folate.

What other foods are rich in folate? More Paleo diet staples… organ meats and avocadoes. A 3-oz. serving of beef liver provides a whopping 215 mcg of folate, while tasty chicken liver pate is a great source at 82mcg per two tablespoons. Avocadoes provide 52 mcg per ½ cup. Finally, if you enjoy seafood, blue crab (44 mcg per 3 oz.) and fish roe (92 mcg per 3 oz.) are also great sources.

Folic acid is a synthetic, man-made supplement that was not part of our evolutionary past. For hundreds of thousands of years our bodies and cells have evolved to process folate and not folic acid. Today’s standard American diet is loaded with fortified folic acid that could potentially contribute to significant adverse health outcomes, such as increased risk of heart disease, cancer, and perhaps even autism. Upgrading your diet to include more natural folate rich foods will provide the ideal platform for optimal health and longevity.

(Note - Expecting mother’s should talk to their doctors about using the 5-MTHFR version of supplemental folate, rather than folic acid.)

Dr. Marc Bubbs ND, CISSN, CSCS


[1] Pitkin R. Folate and neural tube defects. Am J Clin Nutr. 2007 Jan;85(1):285S-288S.

[2] Ganguly P, Alam SF. Role of homocysteine in the development of cardiovascular disease. Nutr J. 2015; 14: 6.

[3] Folate and B12 Deficiency – Retreived from - //

[4] International Meeting for Autism Research in Baltimore. Retrieved from - //

[5] Ebbing M, et al. Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12. JAMA. 2009;302(19):2119-2126.

[6] Cole, B.F., et al., Folic acid for the prevention of colorectal adenomas: a randomized clinical trial. JAMA, 2007. 297(21): p. 2351-9.

[7] Scaglione, F. and G. Panzavolta, Folate, folic acid and 5-methyltetrahydrofolate are not the same thing. Xenobiotica, 2014. 44(5): p. 480-488.


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