Why Folic Acid Is Added to Flour (And the Health Concerns)
Most people have no idea that nearly every loaf of bread, tortilla, muffin, or bagel they buy contains added synthetic folic acid.
While this government policy may have started with good intentions, the health consequences of widespread synthetic nutrient fortification are becoming harder to ignore. Similar to the synthetic iron shards I discussed in my last post, adding isolated nutrients back into refined foods may not be as harmless as it once seemed.
But first, how did we even get to this point?
In the early 1900s, we made a massive shift in how wheat was processed. Instead of small-scale, local milling of whole grains, the food system moved toward industrial, centralized milling. This process strips the wheat kernel of its bran and germ, the parts that contain most of the grain’s vitamins, minerals, and beneficial compounds like polyphenols. What’s left is refined white flour: a shelf-stable starch that has lost much of its original nutrition.
To compensate, manufacturers began adding back a handful of isolated synthetic nutrients, a process called enrichment. Today, refined flour is fortified with synthetic iron and several B vitamins before it’s packaged or used to make bread, muffins, cookies, pizza dough, and countless other processed foods.
The idea sounds reasonable at first: replace what was lost during processing. But it’s somewhat comical to think we can recreate the complexity of a whole food matrix by sprinkling a few isolated nutrients back into refined starch. Whole foods contain thousands of interacting compounds that work together in ways we still don’t fully understand.
Attempting to mimic the nutrition of whole foods with isolated synthetic compounds may also come with unintended consequences.
And it raises an important question:
How can a single standardized vitamin level possibly be appropriate for an entire population? Could this approach increase the risk of overconsumption, especially when multiple fortified foods are eaten every day?
I’ve previously written about the potential concerns surrounding synthetic iron fortification (in this blog post), including its potential to accumulate in the body, contribute to oxidative stress, and disrupt gut health.
But today, I want to focus on another nutrient that’s quietly added to nearly every refined grain product you buy: folic acid.
Folate is Essential
Vitamins and minerals are essential compounds your body needs to run metabolism, the process that produces energy and the molecules required for every system in the body to function properly.
And folate, also known as vitamin B9, is one of these essential nutrients. Folate is required for DNA and RNA synthesis, neurotransmitter production, and amino acid metabolism. It plays a critical role in cell division, red blood cell formation, neurological function, and fetal development. Folate is also central to methylation, a process where the body adds small chemical tags (called methyl groups) to molecules to regulate gene expression, detoxification pathways, and brain chemistry.
Natural folate occurs in foods such as leafy greens, eggs, liver, and legumes.
But folic acid is not the same thing as folate.
Many people assume folic acid is simply a vitamin naturally found in food, but folic acid does not occur naturally in nature. It was first synthesized in a laboratory in the 1940s and is now widely used in dietary supplements and food fortification.
Today, folic acid is commonly added to enriched flour and many processed grain products.
Note: this doesn’t mean every product in these categories contains folic acid. However, many commercially produced breads, cereals, pastas, and baked goods do, because they are made with enriched flour. As a result, most foods served in restaurants also contain folic acid since restaurants typically rely on commercially produced ingredients. There are exceptions. Some smaller brands and certain organic products may not include folic acid if they use unenriched or whole-grain flours. This is why it’s always important to read ingredient labels carefully.
However, these images document how many fortified products people are exposed to on a daily basis.
In 1998, the U.S. government mandated that folic acid be added to enriched wheat flour and cornmeal (products labeled as ‘enriched’. Note, this does not include organic products since organic does not allow synthetic nutrients).
Because enriched flour is used in so many foods, this meant folic acid was added to a large portion of the processed food supply, including bread, pasta, cereal, cookies, muffins, pizza dough, and more.
In 2016, the FDA approved a rule allowing manufacturers to add folic acid to corn masa flour, the flour used to make tortillas, tamales, and other traditional foods, though this remains voluntary at the federal level. But recently, some states have gone further. Beginning in 2026, California requires folic acid fortification of most corn masa flour used in tortillas, and Alabama has passed a similar law. Other states are now considering comparable policies.
These policies were proposed because corn tortillas are a staple food for many people (particularly within Hispanic and Latin American communities) who may consume fewer wheat-based products and therefore were not receiving folic acid through the original fortification program. So the goal was to extend folic acid exposure to a larger portion of the population.
The original reason for folic acid fortification was to reduce the risk of neural tube defects. The scientific literature is well established that adequate folate status during early pregnancy does reduce the risk of neural tube defects. (ref)
But adequate folate status is not the same thing as consuming synthetic folic acid. Neural tube development depends on a network of nutrients involved in DNA synthesis and methylation, including vitamin B12, choline, riboflavin (B2), vitamin B6, and zinc.
Yet instead of focusing on overall maternal nutrition, public health policy has largely centered on adding one synthetic nutrient to the food supply.
And increasingly, research suggests that chronic exposure to high levels of folic acid may come with unintended health consequences.
Folate vs. Folic Acid: They Are Not the Same
While folic acid is often described as a supplemental form of folate, there is an important distinction between these compounds that leads to real differences in how they behave in the body.
The image below highlights the difference between folate (natural forms) and folic acid (synthetic), they are not the same molecule!
Natural folate in foods commonly exists as 5-methyltetrahydrofolate (5-MTHF). This form contains a methyl group (CH₃) and is considered biologically active, meaning it can readily participate in the body’s methylation pathways and donate its methyl group for important biochemical processes.
Folic acid, on the other hand, is a synthetic, oxidized compound that lacks this methyl group. Before the body can use it, folic acid must first be converted through several enzymatic steps into active folate forms like 5-MTHF.
Natural folate delivered through whole foods comes packaged within a complex whole-food nutrient network, where vitamins, minerals, enzymes, and cofactors work together to support metabolism. Folate metabolism relies on several key nutrients, including Vit B12, Vit B6, Vit B2, and Choline. These nutrients interact within the body’s one-carbon metabolism and methylation pathways, helping regulate DNA synthesis, neurotransmitter production, and cellular repair.
Synthetic fortification, however, isolates a single compound and adds it back into refined foods without this broader nutritional context/package. This difference may help explain why folate from whole foods and folic acid from fortified foods do not always produce identical biological effects.
Folic Acid Accumulation
Because folic acid is a synthetic compound, the body must first convert it into biologically active folate before it can be used. This conversion requires several enzymatic steps, and one of the key enzymes involved is dihydrofolate reductase (DHFR), which begins the process of converting folic acid into active folate forms.
The problem is that DHFR works relatively slowly in humans (ref) Research suggests that the enzyme becomes saturated once folic acid intake exceeds a certain threshold (~200 mcg (ref)). When intake exceeds this metabolic capacity, the excess folic acid cannot be fully converted and instead circulates in the bloodstream as unmetabolized folic acid (UMFA). (ref)
In other words, once the body’s processing capacity is exceeded, folic acid begins to accumulate.
Several studies have reported the presence of unmetabolized folic acid in the blood following the consumption of folic acid supplements or fortified foods. (ref)
In fact, detectable levels of UMFA have been found in a large majority of the U.S. population (over 95%). (ref)
This accumulation is likely driven by the modern food environment. Because folic acid is added to enriched flour and many processed foods (and is also present in multivitamins and prenatal supplements) daily intake can easily exceed the amount the body can efficiently metabolize.
Estimates suggest the average American adult consumes 600–800 mcg or more of folic acid per day (ref), 3-4X the level at which the DHFR enzyme may begin to saturate (200 mcg).
The low activity of DHFR in the human liver, combined with high folic acid exposure from fortified foods and supplements, may therefore result in unnaturally elevated levels of unmetabolized folic acid entering systemic circulation.
Another complicating factor is vitamin B12 status. Folate metabolism relies on adequate B12 levels, and low B12 can impair the normal use of natural folate from foods. Synthetic folic acid can sometimes temporarily improve blood markers by masking symptoms of B12 deficiency (ref), without correcting the underlying problem.
Variations in the MTHFR gene, which affect how efficiently folate is converted into active forms, are common in the population. For individuals with these variants, high intake of synthetic folic acid may further disrupt normal folate metabolism.
Taken together, these factors suggest that widespread exposure to synthetic folic acid, far above levels historically present in the human diet, may create metabolic conditions the body was not designed to handle.
Health Risks Linked to Excess Folic Acid Exposure
When folic acid accumulates in circulation as unmetabolized folic acid (UMFA), researchers have raised concerns that it may interfere with normal folate metabolism. Some evidence suggests UMFA may compete with natural folate forms for cellular transport and receptors, potentially affecting how folate is delivered to tissues such as the brain.
As a result, a growing body of research has linked elevated folic acid exposure or circulating UMFA to several potential health concerns, including:
> Interference with natural folate transport into the brain, which may influence neurotransmitter production. (ref, ref)
> Altered neurodevelopment during pregnancy. High folic acid exposure in the womb has been associated in some studies with changes in neurodevelopment and increased autism risk. (ref, ref) The Boston Birth Cohort study (ref) measured cord blood UMFA and found that babies with the highest UMFA levels had more than double the risk of autism compared to those with lower levels.
> Disruption of sperm epigenetics. A study in men given high-dose folic acid found widespread changes in DNA methylation patterns in sperm, suggesting potential impacts on male fertility and embryonic development. (ref)
> Immune system effects. Some research suggests elevated folic acid exposure may reduce natural killer cell activity, an important component of your natural immune defense. (ref, ref)
> Potential cardiovascular effects, including associations with higher homocysteine-related metabolic disturbances. (ref)
> Increased Cancer risk. (ref, ref, ref, ref)
> Cognitive effects in older adults. (ref)
Natural folate forms found in whole foods support the body’s normal folate metabolism while also providing the broader network of nutrients required for healthy methylation and cellular function. Folic acid is processed and utilized differently.
Hitting Folate Needs Through Food
Some of the foods highest in folate (which is different than folic acid) include:
- Leafy greens such as spinach and collard greens
- Asparagus and broccoli
- Fresh parsley
- Eggs
- Liver (especially chicken liver)
- Legumes like black beans, navy beans, and lentils
- Whole wheat sourdough bread
- Oranges and other citrus fruits
And there are many ways to meet the recommended intake (RDA) of 400 mcg through whole foods. Here are just a few examples!
Example 1
- - ½ cup cooked black beans
- - ½ cup cooked spinach
- - ½ cup cooked asparagus
Total: ~408 mcg
Example 2
- - 1 oz cooked chicken liver
- - ½ cup cooked collard greens
- - ½ cup cooked asparagus
Total: ~400 mcg
Example 3
- - 1 cup cooked asparagus
- - ½ cup cooked broccoli
- - 1 large orange
- - ¼ cup fresh parsley
Total: ~406 mcg
(In addition to levels consumed in various other foods throughout the day).
Tracking your intake using tools like Cronometer can help you understand how your diet supports your nutrient needs, and if you are hitting the RDA for certain micronutrients.
If dietary intake is inadequate due to food availability or food tolerance, it may be preferable to supplement with more naturally occurring folate forms rather than synthetic folic acid. Some practitioners recommend 5-methyltetrahydrofolate (5-MTHF), L-methylfolate, or Metafolin. And avoid products that list “folic acid” as the primary folate source.
As always, consult your doctor, fertility specialist, obstetrician, or other healthcare professional before making significant changes to supplementation.
How to Avoid Folic Acid in Foods
The government fortification mandate applies only to products labeled “enriched”, which is very commonly used in the conventional food system. Manufacturers can still sell unenriched flour, which does not require folic acid fortification. But there is no way to know unless you read ingredient lists.
Many organic grain products also avoid synthetic fortification because organic standards generally prohibit adding synthetic vitamins.
Tips:
- > Read ingredient labels carefully
- > Avoid products labeled “enriched” or “fortified” flour
- > Check multivitamins and prenatal vitamins for folic acid
- > Understand that most grain products at restaurants/fast food restaurants will include it
- > Watch for folic acid in:
- breads and cereals
- pasta
- protein bars
- energy drinks
- protein drinks
- baked goods
- baby formula
- multivitamins and supplements
If the label lists “folic acid,” consider choosing an alternative product.
Consuming folic acid occasionally is not a concern. It’s the repeated, daily exposure where UMFA build up can occur over time!
Conclusion
Some people tolerate enriched flour and folic acid fortification without obvious issues.
But it’s unrealistic to assume that adding isolated synthetic nutrients to the food supply will work equally well for an entire population. Humans have different diets, lifestyles, and metabolic capacities. What works for one person may create problems for another!
And increasingly, we are beginning to see the consequences of relying on isolated compounds that were never meant to function alone. In whole foods, vitamins and minerals exist within a complex nutritional network where they work together alongside enzymes, cofactors, and other compounds that support proper metabolism.
Another important question that we haven’t studied in long term safety studies is cumulative exposure.
Many people today consume multiple fortified foods throughout the day: bread, cereal, pasta, snack bars, energy drinks, protein powders, and supplements. When these sources are combined, we may be exposing the body to a “kitchen sink” of isolated nutrients that far exceed what would naturally occur in food.
As always, the safest and most balanced way to obtain vitamins and minerals is to let nature provide them through whole foods.
