Folic Acid: friend or foe?

Folate (vitamin B9) is a generic term for a naturally occurring family of B- group vitamins. It is essential for human health, and it is found naturally in food such as green leafy vegetables, pulses, orange juice, yeast extract. Folic acid is a synthetic, cheap to produce, very stable form of vitamin B9, commonly used in the form of supplement. Folates are required for the body to make DNA and RNA, for cell division, and, along with vitamin B12, for the production of healthy red blood cells.

However, folate is mainly known from its crucial role in the development of an unborn baby’s spinal cord. It has been proven, by numbers of studies, that folic acid supplementation before and during early pregnancy can markedly decrease the incidence of most common spina bifida as well as other neural tube defects (NTDs)

NTDs are a group of serious birth defects that affect the developing nervous system. Although they are not very common, frequency approx. 1/1000, the severity of the problem is extreme. The impact of having a baby with a NTD is profound emotionally, spiritually and financially.

There are currently over 70 countries that implement mandatory fortification with folic acid. UK, was considering for a while whether to replace the existing policy (voluntary food fortification together with supplementation) and mandate the fortification of white wheat flour with folic acid. And last month they decided to do so…and it is a decision that potentially push a significant number of the population above the guideline upper limit for folic acid and exposure to an increased intake of this synthetic vitamin raises questions about its safety.

Evidence of folic acid having a protective effect against NDTs is overwhelming and led to mandatory food fortification in many countries. Although seen by many as the safe action, others continue to raise scientific concerns that it may have adverse effects. Additionally, introducing mandatory food fortification is an ethical and technical challenge

The scientific world continuously explores the impact of regular intake of folic acid on human body. The main concern around the topic is the association of a high intake of folic acid with masking B12 deficiency , common among older people, that may lead to dangerous condition of neural system. Neurological harm from long term exposure exists from doses between 0.5- 1mg and not as was thought earlier from does over 1mg only.

Studies carried out in Chile, where mandatory fortification is in force since 2000 provide evidence of an association between regular folic acid intake and colon cancer. Although fortification reached the target of decreasing NTDs (by about 50%) the prevalence of colon cancer increased by 25%.

Folic acid has a dual effect on cancer. It appears to be protective against cancer initiation but may promote tumour progression. A number of studies looked at the connection between folic acid and other cancers, such as breast cancer or prostate. Results of those studies show evidence for the existence of such connection. Although in countries such as USA or Canada the prevalence in NTDs since mandatory fortification was introduced decreased dramatically, up to 40% cases remain nonresponsive due to

MTHFR genetic polymorphism affecting the folic acid metabolic pathway . In fact, in Spain the prevalence of MTHFR has doubled since folic acid in the form of supplements was introduced in 1982.

In US, some of the fortified products were found to include doses of folic acid, even 2 times higher than the amount listed on the label, what can led to high or even toxic intakes among population.

Additionally, there is evidence that folic acid may interact with a number of medicines, for example those treating patients with epilepsy or malaria.

Despite of a number of studies presenting clear evidence of the potential harm of folic acid most health and nutrition organizations promote the opinion that

fortification with folic acid is safe and food fortification should be mandatory to reduce NTDs prevalence and socio- economic inequalities in NTDs prevalence. The media follows the same attitude toward fortification. It is well known that public opinion greatly depends on how media portray the issue. So a massive number of newspapers articles show only one side of the argument and people believe this is the only side...

However, from the medical viewpoint it is not usual to claim that treatment is safe only because it is effective in treating or preventing one condition.