More warnings against fortifying flour with folic acid have emerged, following evidence that this could lead to increased cancer rates.Two commentaries published in this month's issue of Nutrition Reviews call for a careful reconsideration of fortification programs, since adding folic acid to the diet may benefit some consumers but cause damage to others.Scientists Young-In Kim and Noel Solomons state that the introduction of flour fortified with folic acid into common foods was followed by an increase in colon cancer diagnoses in the US and Canada."One size of dietary folic acid exposure does not fit all," wrote Solomons, Director of the Center for Studies of Sensory Impairment, Aging and Metabolism (CeSSIAM) in Guatemala City, and head of the Task-Force on Diet, Nutrition and Long-term Health of the International Union of Nutritional Sciences.The commentaries come at the same time as a new report published in the British Journal of Nutrition that claims that folic acid fortification may lead to a range of health problems.Scientists at the UK Institute of Food Research wrote that folates in the blood stream could provoke a number of complaints such as leukaemia, arthritis, bowel cancer and ectopic pregnancies in people already suffering from health problems.The emergence of such evidence casts doubts over decisions by governments worldwide to approve mandatory folic acid fortification. This occurs in some 40 countries, including the US, Canada and Chile, while the move is currently being debated by regulators in Australia, New Zealand and Ireland.Folic acid, a chemical form of a common B vitamin (folate), has been linked to a reduced rate of a specific birth defect that affected the development of the spinal cord and central nervous system.For nearly a decade, folic acid has been added to wheat flour and other grain products in the US and Canada. However, the new reviews claim that during the same period, rates of colorectal cancer in the US inexplicably began rising, even as regular colonoscopy check-ups became more common. In Canada, where folic acid supplementation was introduced a bit later, the same trend was observed."Folic acid supplementation wields a double-edged sword. It may be beneficial or harmful, depending on the timing of intervention," said Young-In Kim, Associate Professor of Medicine and Nutritional Sciences at the University of Toronto.Exposure to high intakes of folic acid in early life and young adulthood may provide life-long protection from the tendency for cancer formation in different organs, such as the large intestines, whereas such exposures later in life, when cell damage has occurred, can spur on the advance of the tumor, said the scientists.Since the risk-benefit value of fortification varies according to age, they recommend a reevaluation of the manner in which folic acid to prevent birth defects is delivered to the public. Suggestions include targeting women of reproductive age while reducing folic acid levels in foods for which fortification is optional (such as ready-to-eat cereals and commercial drinks).This is not the first time that a possible negative impact of folic acid fortification has been brought into the spotlight. Indeed, it first looked like the UK's Food Standards Agency (FSA) would issue its positive advice on fortification in summer 2006. The agency's Scientific Advisory Group on Nutrition (SACN) then said, however, that it needed more time to look at additional evidence on the risks and benefits of fortification, particularly in relation to increasing folate intake over 1mg per day. The FSA last considered mandatory fortification in 2002, but the SACN decided not to adopt it at that time because of concerns that folate consumption in excess of 1000 micrograms (1mg) per day could delay the detection of vitamin B12 deficiency (which can have severe neurological consequences) in older people. Since then, some research has indicated that B12 deficiency would be masked only with folate consumption of more than 5000 micrograms per day. When the SACN's advice was finally forthcoming, it came with the condition that there be controls on voluntary fortification, and clear guidance be given on the appropriate use of supplements containing folic acid.
