The prevalence of folate deficiency in Australians has significantly reduced since the introduction of mandatory fortification with folic acid of wheat flour used in breadmaking, according to a study published in the Medical Journal of Australia.

Researchers from the Institute of Haematology at the Royal Prince Alfred Hospital in Sydney determined the impact of mandatory fortification with folic acid on the blood folate levels of Australians since its introduction in September 2009.

The researchers conducted a retrospective analysis of serum and red blood cell (RBC) folate levels in 20,592 blood samples collected between April 2007 and April 2010. Between April 2009 and April 2010, there was a 77 per cent reduction in the prevalence of low serum folate levels and an 85 per cent reduction in the prevalence of low RBC folate levels. Overall, there was a 31 per cent increase in the mean serum folate level.

Dr Ross Brown, Principal Hospital Scientist, said that since 2009, Australian millers had been required to add folic acid to wheat flour for breadmaking in an effort to reduce the incidence of neural tube defects in newborn infants.

"While increased folic acid intake can reduce the incidence of neural tube defects, it cannot prevent all cases," Dr Brown said.

"An RBC folate level of 906 nmol/L is considered to significantly reduce the risk of neural tube defects.

"In our group of Australian patients, 64 per cent of women had an RBC folate level of greater than 906 nmol/L in April 2010.

"The impact of mandatory fortification on the incidence of neural tube defects has still not been evaluated," Dr Brown said.

The Medical Journal of Australia is a publication of the Australian Medical Association.