Since 1996, neural-tube defects have decreased by over 25 percent in the United States and Canada. No decrease has occurred in Europe.

What is the reason for the decrease in the United States and Canada?

Answer: Cereals and breads in the United States and Canada are now fortified with folic acid.

Explanation:

Many countries have commanded the addition of folic acid to certain foods to reduce the possibilities of the appearance of neural tube defects, with quite successful results.

In 1998, the United States required folic acid fortification of all cereal grain products identified as enriched. That same year, Canada required fortification of white flour, enriched pasta, and cornmeal.

Costa Rica, Chile and South Africa have also experienced a decrease in neural tube defects as a consequence of the fortification process.