Scientists Crack Mystery of How Folic Acid Protects Babies

For generations, doctors have known that folic acid prevents devastating birth defects, but they never understood why. Now, scientists from Hebrew University of Jerusalem and Universidade NOVA de Lisboa have cracked the code.

The discovery centers on how a baby's brain and spinal cord form in the earliest days of pregnancy. Before an embryo even looks human, a sheet of cells called the neural plate folds upward like origami, and its edges must meet and close like a zipper to create the neural tube.

When that zipper doesn't close properly, babies can be born with neural tube defects. Folic acid has long prevented many of these cases, but scientists couldn't explain how a simple vitamin accomplished something so complex.

The research team, led by Ph.D. student Tamir Edri, discovered that folic acid activates a gene called ALDH1L1. This gene produces an enzyme that transforms a molecule from vitamin A into retinoic acid, which acts like an instruction manual for developing cells.

Retinoic acid tells cells when to grow, what to become, where to go, and when to stop dividing. Without these precise instructions at exactly the right time, development goes wrong.

To test their theory, the researchers worked with frog embryos, which develop similarly to human babies in early stages. They created embryos with neural tube problems and treated them with folic acid, which helped many develop normally.

Then came the crucial experiment. When scientists blocked the ALDH1L1 gene, folic acid lost its protective power completely.

The team also discovered that when retinoic acid levels dropped too low, nervous system cells multiplied too quickly and the neural plate expanded abnormally. Folic acid corrected this runaway growth, but only when ALDH1L1 was functioning properly.

In another surprising twist, small amounts of vitamin A improved folic acid's effectiveness at low doses. However, the researchers strongly caution that pregnant women should not take extra vitamin A, as too much causes serious birth defects.

Why This Inspires

This breakthrough represents decades of scientific detective work finally paying off. Understanding how folic acid works opens doors to helping the pregnancies where it currently falls short.

The discovery also explains why folic acid prevents many neural tube defects but not all of them. Problems in the ALDH1L1 pathway could be one reason, giving researchers a new target for protecting even more babies.

The findings appeared in the Proceedings of the National Academy of Sciences in July 2026, marking a milestone in prenatal health. What started as a simple question about a common vitamin has revealed an elegant molecular dance that helps build healthy babies.

After decades of knowing folic acid works without knowing why, science has finally illuminated one of pregnancy's most important protective mechanisms.