Folic Acid Fortification and a Better Way for Folate Intake

Folic acid fortification is a preventative measure that governments have undertaken for almost three decades to reduce the incidence of neural tube defects (NTDs) such as spina bifida. 

Folic acid is added to everyday foods such as flour and cereals during the manufacturing process to increase dietary folate intake in women of childbearing age, including those who are not planning to get pregnant and whose nutritional intake may be otherwise inadequate. 

This decision is based on studies from the early 90s which showed that folic acid (pteroylmonoglutamic acid) supplementation prior to conception and during the first 12 weeks of pregnancy reduced the incidence of neural tube defects (NTDs) by almost 80%.¹

Research suggests that more than half of women of childbearing age do not consume the recommended daily intake required to reduce the risk of NTDs.²

The US Public Health Service recommends that women of childbearing age consume at least 400 μg of folic acid daily to prevent NTDs, but no more than 1,000 μg/day because of the unknown health effects of excessive folic acid.³

The foods most commonly fortified with folic acid are wheat flour, maize (corn) flour and rice. This typically includes: 

• Enriched breads
• Flours
• Pasta
• Rice
• Cornmeal
• Fortified corn masa flour
• Fortified breakfast cereals

In the US and Canada, a minimum of 140 μg of folic acid is added per 100 g of cereal grains (150 μg in Canada), but some brands include up to 400 mcg per single serving.⁴ These levels were expected to provide roughly 100-200 μg of additional folic acid per day in women of childbearing age.

Globally, more than 80 countries have passed legislation or regulations to mandate fortification of food sources with folic acid on the basis of information from the Global Fortification Data Exchange, UN Food and Agriculture Organization and WHO.⁵ This includes the US, Canada, Australia, New Zealand, many South American countries and several countries in Africa.

Mandatory folic acid fortification was first implemented in the United States and Canada in 1998, followed by many countries in subsequent years.

Currently, folic acid fortification is only voluntary in the United Kingdom and Europe, but mandatory folic acid fortification of non-wholemeal wheat flour in the United Kingdom will be required by law from the end of 2026.⁶

Concerns about folic acid intake have increased in recent years.

Research has highlighted the negative effects of high folate intake, particularly in regards to folate masking B12 deficiency. High folate levels can appear to improve symptoms of anemia even while B12 is deficient, which can mean B12 deficiency is undetected. Prolonged B12 deficiency can lead to neurological impairment and other health complications.⁷

Studies have also shown the potential effects of folic acid intake on increasing cardiometabolic risk and the higher rates of diabetes in children in countries where B12 deficiency is common.⁸

Another major concern involves people with MTHFR mutations. The methylenetetrahydrofolate reductase (MTHFR) gene produces the enzyme that helps convert folate into its active form (methylfolate) which can then convert homocysteine into methionine. Without methylfolate, homocysteine builds up in the body, impairing the production of important neurotransmitters such as serotonin and norepinephrine. Increased homocysteine is also linked to cardiovascular disease, stroke and dementia.

People with a mutation in the MTHFR gene have a decreased ability to metabolize folic acid. If unmetabolized, folic acid can build up in the blood, which has been linked to potential health risks. Animal studies suggest that excessive folic acid exposure may influence embryonic development and gene expression, but the relevance to humans is not fully established.⁹

Earlier studies have suggested that around 40% of older adults in the US have persistent unmetabolized folic acid (UMFA), which has been linked to an increased risk of cancer.¹⁰

The safe and effective alternative to folic acid is methylfolate, the active form of folate. Multiple studies have shown that risks associated with folic acid fortification can be eliminated by substituting folic acid with 5-methyltetrahydrofolate (methylfolate), which does not require further conversion in the body, including in those with MTHFR genetic mutations.¹¹