Folic acid linked to autism

PREGNANT women who take too much folic acid and vitamin B12 could increase the risk of their baby developing autism by up to 17 times, research warns.

Mothers-to-be are often told to take folate supplements as too little is bad for the developing brain and nervous system of babies.

Deficiencies have been linked to birth defects and a higher risk of the mental disorder but a study suggests that it is also possible to take too much.

Folate or vitamin B12 is found in fruit and vegetables and the synthetic version, folic acid, is used to fortify cereals and breads.

Researchers at Johns Hopkins University in the US found that taking more than four times the recommended amount of folic acid doubles the risk of babies developing the mental disorder.

High vitamin B12 levels trebled the risk and, if levels of both substances were extremely high, it could increase by 17.6 times.

However, the study authors stressed that pregnant women should not reject supplements.