Researchers at Lund University in Sweden have discovered that too much vitamin A negatively effects the formation of blood cells during human embryonic development, suggesting that pregnant women should avoid foods high in the vitamin.

The signal molecule, retinoic acid, is a product of vitamin A, which helps to instruct how different types of tissue are formed in a growing embryo. For the first time, Professor Niels-Bjarne Woods’ laboratory, Lund Stem Cell Center in Sweden, studied the effects of retinoic acid on how blood cells develop from human stem cells. In the laboratory model, the stem cells are exposed to specific signal molecules, spurring them to develop into blood-producing cells.
The researchers observed that increased levels of retinoic acid drastically decreased the number of blood cells that could be produced. A reduction in the retinoic acid, though, raised the production of blood cells by 300 percent.

 While the concept that retinoic acid affects blood cell development has been demonstrated in animal models, this is the first time the experiments have been done using human cells.

Researchers have long known that too much vitamin A can be harmful to a fetus, raising the risk of fetal malformation and miscarriage. Pregnant women have been advised to limit their consumption of foods that are high in vitamin A in the form of retinoids, such as liver.

Woods is trying to find ways of artificially generating blood stem cells for use in blood stem cell transplants to patients with blood disorders and cancers, who do not have access to a suitable donor.

“The current research findings increase our understanding of the complexity of the process of blood formation during embryonic development. We hope that this, together with future discoveries, will lead to the generation of blood stem cells in the laboratory, which in turn can be used to treat blood disorders and malignancies,” says Woods.

Source: Lund University