5 November 2007
Cancer Concerns From Folate Additives
Folic acid, which is sometimes added to bread and flour to prevent birth defects, may cause cancer, say researchers from the Institute of Food Research (IFR). Folic acid is a synthetic form of folate, a B vitamin found in a wide variety of foods including liver and green leafy vegetables. Folates are metabolized in the gut, whereas in a paper to be published in the British Journal of Nutrition, IFR scientists suggest that folic acid is metabolized in the liver. The liver is an easily saturated system, and fortification could lead to significant unmetabolized folic acid entering the blood stream, with the potential to cause a number of health problems.
The researchers noted that even with doses of half the amount being proposed for fortification in the UK, the liver becomes saturated and unmetabolized folic acid floats around the blood stream. "This can cause problems for people being treated for leukemia and arthritis, women being treated for ectopic pregnancies, men with a family history of bowel cancer, people with blocked arteries being treated with a stent and elderly people with poor vitamin B status. For women undergoing in-vitro fertilization, it can also increase the likelihood of conceiving multiple embryos, with all the associated risks for the mother and babies. It could take 20 years for any potential harmful effects of unmetabolized folic acid to become apparent, the study reported.
Folic acid fortification can exhibit Jekyll and Hyde characteristics, say the scientists behind the study, providing protection in some people while causing harm to others. Previous studies have confirmed that unmetabolized folic acid accelerates cognitive decline in the elderly with low vitamin B12 status, while those with normal vitamin B12 status may be protected against cognitive impairment.
Similarly, dietary folates have a protective effect against cancer, but folic acid supplementation may increase the incidence of bowel cancer. It may also increase the incidence of breast cancer in postmenopausal women. "We challenge the underlying scientific premise behind this consensus. This has important implications for the use of folic acid in fortification, because even at low doses it could lead to over consumption of folic acid with its inherent risks," said IFR's Dr Siān Astley.
Low Folate Levels Linked To Cigarette Smoke
Source: Norwich BioScience Institutes