Scientists are warning that the popularity of low-carb diets could result in a sharp increase in birth defects and childhood cancers.

According to researchers at the Toronto Hospital for Sick Children, Canada, foods such as bread, pasta and citrus juices are forbidden on regimes like the Atkins diet, but are essential in providing mothers with folic acid, a B-vitamin known to prevent neural tube defects.

The hospital told the Globe & Mail newspaper that since 1998, white flour, white pasta and cornmeal in Canada have been fortified with folic acid. In turn, birth defects have fallen by 50% and occurrences of neuroblastoma - a common childhood cancer - have fallen by 60%.