So should all pregnant women start taking B3 supplements? Not so fast. While this is an interesting and well-done study, the researchers didn’t actually give vitamin B3 to any humans, so we need a lot more information before we can recommend it.
What the study found
The study identified genetic causes of a rare type of birth defect called “VACTERL association”. VACTERL stands for vertebral defects, anal atresia (problems with the tissue closing the anus), cardiac defects, tracheo-esophageal fistula (an abnormal connection between the windpipe and the foodpipe), renal anomalies (kidney defects), and limb abnormalities. Affected babies have anomalies in at least three of these.
The study authors looked at the genes of 13 families affected by this type of birth defect. For the defect to be passed on to offspring it has to be present in both parents’ genes – if it’s only present in one gene the other healthy one will compensate.
They pinpointed the variations in two genes responsible for these defects in four of the families. These two genes play a role in making “nicotinamide adenine dinucleotide” or NAD, which helps cells makeenergy out of glucose. NAD also assists in repairing DNA. NAD is synthesised in the body from tryptophan, an amino acid, or from niacin, also known as vitamin B3.
Then the authors genetically engineered mice and deleted these genes. They found that without them the mice had NAD deficiency, and similar malformations in their offspring.
However, when they provided extra niacin to pregnant mice, the pups were relatively normal despite the absent gene.
What does this mean?
This does NOT mean that taking niacin/vitamin B3 in pregnancy prevents miscarriages and all birth defects.
It means that high levels of niacin in pregnancy compensates for defects in the two selected genes, and prevents mice from experiencing miscarriage and birth defects in offspring. The paper does not report on human miscarriage or on malformations in human organs. The study did not supplement pregnant women with vitamin B3, or with anything else.