It's Time To Abandon Dangerous Folic Acid Fortification Programs and Stick To Folates
It's an embarrassing fact, but more than half of dieticians think folic acid is naturally found in foods. It isn't and never was. Only folate is found in foods such as lentils, beans, spinach and other greens. The body does not metabolize folic acid in the same way it does folate. Researchers from the Institute of Food Research and Newcastle University have confirmed that the body processes synthetically-produced folic acid differently to the natural counterpart found in vegetables. This leads to unmetabolized folic acid circulating in the bloodstream which is eventually metabolized by the liver, but the process is slow, inefficient and possibly toxic.
In countries with mandatory folic acid fortification programmes, neural tube defects such as Spina Bifida and Anencephaly, which are associated with low folate levels, have fallen by up to 46%.
Folate is a very important B vitamin, and low levels may be involved in certain carcinogenic processes. If more people could supplement their folate intake from fruits and legumes, rather than from a folic acid supplement it could condition the population to regulate from a natural source as synthetic fortification is far inferior to natural sources of folate. These foods have other cancer-fighting properties and can help protect against other chronic diseases.
We may be over-exposing our populations to folic acid One study found that three quarters of post-menopausal women had folic acid circulating in their bloodstream.
A number of studies have flagged potential problems with excess folic acid, including compromising the immune system, masking vitamin B deficiency and increasing the risk of some forms of cancer.
The study, published in PloS One, investigated whether folic acid supplementation is linked to an increased risk for the progression of established mammary tumours using a rat model after previous research suggested a link between high intakes of the B vitamin and breast cancer risk.
As the UK considers whether to follow the example of the USA, Canada and Australia and 70+ other nations in introducing mandatory folic acid fortification programmes, the researchers are urging the government to either consider using a different folate form, or further investigate the implications of excess folic acid.
Fortify with Folates
"We only carry out studies and don't make policy decisions, but we'd hope that future decisions about fortification with folic acid take into account our central finding -- that we don't metabolise folic acid in the same way as natural folates," stated research leader Paul Finglas.
"Where fortification does happen, we'd suggest the forms of methyltetrahydrofolic acid (the natural form of the vitamin in food and main circulating form in the body) could be considered as an alternate fortificant to folic acid now that more stable synthetic forms have been made available commercially."
The folate forms he is referring to are Merck's Metafolin and Quatrefolic from Gnosis, both of which have been decreed safe for use in supplements and foods by the EFSA (European Food Safety Authority). Although no long-term studies have ever been established.
Folic Acid Metabolism
The researchers reported that 86% of folic acid in the hepatic portal vein (which carries blood from the gut to the liver) was unmetabolized, whereas almost all of the natural folate was converted correctly.
"Folates are taken up by the cells lining the gut and are metabolized by an enzyme called 5,10-methylene THF into a form called 5-Methylformate (5-MTHF) -- the biologically active form," said Finglas, explaining the metabolism process.
He said the assumption, based on studies in rats, was that the gut lining could do the same with folic acid, using an enzyme called Dihydrofolate reductase (DHFR).
"However, what the study showed was that the gut lining doesn't metabolise folic acid to 5-MTHF anywhere near as efficiently as it metabolises natural folates, as we could see much unmetabolized folic acid in the hepatic portal vein. The liver becomes overloaded and unmetabolized folic acid enters the blood circulatory system," explained Finglas.
He said that although the liver does eventually metabolise the folic acid that has entered the circulatory system, the effect this has on the health is unknown.