WELLINGTON, Aug. 14 (Xinhua) -- All non-organic bread-making wheat flour in New Zealand will be fortified with folic acid from Monday to prevent birth defects.

The measure is to prevent neural tube defects, such as spina bifida. In New Zealand, these occur in about 10.6 per 10,000 live births and are associated with lifelong disability.

With the announcement that folic acid will be added to bread-making flour, New Zealand has joined more than 70 countries that already require folic acid to be added to a food staple to prevent neural tube defects, said Kathryn Bradbury, senior research fellow at the University of Auckland's School of Population Health.

Studies have shown that folic acid supplements can reduce the occurrence of these neural tube defects during pregnancy by up to 70 percent.

Folic acid supplements must be taken before conception to be fully effective, but more than half of pregnancies in New Zealand are unplanned.

"Adequate folate intake in pregnancy is also a health equity issue," said Louise Brough, senior lecturer in Nutrition Science at the Massey University, adding Maori, Pacific people, young mothers and those on lower incomes are less likely to take folic acid supplements, especially preconception due to high levels of unplanned pregnancy.

A 2011 New Zealand survey showed only one-third of women consumed folic acid supplements prior to pregnancy.

Bread is an excellent vehicle for providing folate as it is widely consumed throughout New Zealand, with higher intakes among those on lower incomes, Brough said.

Fortification of bread with folic acid became mandatory in Australia in 2009, and it is estimated that neural tube defects were reduced by 14 percent among all women, but by 74 percent among Aboriginal Australians, she said.

There are also concerns around "mass medication" and the effects of higher folic acid intake on other population groups, Brough said. However, she said flour has been fortified with folic acid in the United States for over two decades and neural tube defect-affected pregnancies have reduced, without any demonstrable adverse outcomes in the population.

"Folate, also known as vitamin B9, is an important vitamin that many of us do not get enough of," said Associate Professor Lynne Chepulis of the University of Waikato.

There is good evidence that folic acid supplementation is still highly beneficial outside of pregnancy, such as in reducing the risk of cardiovascular disease and even some cancers, Chepulis said, adding optimal folate levels are needed throughout life, but particularly, during periods of rapid growth.

Emeritus Professor Elaine Rush of the Auckland University of Technology called for conducting a national nutrition survey to enable the fortification of bread with folic acid to reach the target consumers, such as women of childbearing age, which can also inform the fortification of other foods, such as rice.