Vitamin B3 Linked For the First Time to Birth Defects

A common vitamin could be the key against birth defects, and miscarriages too, during pregnancy. For the first time, a team of scientists from the Victor Chang Cardiac Research Institute linked the possibility of lowering rate of birth defects with vitamin B3 (also known as nicotinamide or niacin). This vitamin is required for the production of a molecule called NAD (nicotinamide adenine dinucleotide) which is essential to a child’s development inside a womb.

Every year, 303,000 newborns with birth defects die within four weeks of birth and the survivors carry long-term disabilities. Genetic and environmental factors are major risk factors for not-yet-born babies to develop abnormalities but few studies also point to the mother’s nutritional status during pregnancy, like excess intake of vitamin A or folate deficiency.

In 2005, the research team studied a case of a baby born with heart, backbone and ribs defects. Genetic sequencing revealed that both parents of the baby had mutations in the gene that manages the production of NAD in the body. Years later, the team encountered the exact situation with three more families. They studied the genetic data of all four families and the results were published in New England Journal of Medicine.

To prove the link between the mutation and birth defect, the team used the gene editing CRISPR technique to cut out normal NAD genes in mice. Surprisingly, the mice’s babies turned out healthy. They eventually realized that NAD can be alternatively made through nicotinamide, which is abundant in the mice’s diet. They fed another group of pregnant mutant mice, this time without the vitamin. Some of the pups died inside the womb (a version of miscarriage in mice) and those who were born showed defects similar to those of the children of the affected families.

The discovery of NAD is “the most important [one] for pregnant women since folate”, says Sally Dunwoodie, developmental geneticist and a member of the research team. While B3 can be formed naturally in the body through food intake, the study suggests that in families who carry the mutation, such birth defects might be prevented from developing during pregnancy if there is sufficient B3 in the mother’s diet. A third of pregnant women have low B3 levels during the first trimester of pregnancy while 60% have the deficiency in the third. Vitamin B3 is present in meats, eggs, cheese, fish, nuts and green vegetables and the recommended intake is 18 milligrams daily.

The results with mice are promising but researchers are still unsure if the benefits of the study can be fully translated to humans. Not too many types of birth defects are caused by nutritional B3 deficiency and most women are already getting the vitamin from food sources so supplementation might have little or no effect.

In case treatment is the viable option, it is only when a pregnant woman has problems with nutrient absorption. Only then can supplementation be recommended. The next step for researchers now is to develop a diagnostic test that can measure NAD levels to properly identify pregnant women who can actually benefit from the study’s results.