Research has shown a pregnant mother’s vitamin D supply is transferred to the baby in her womb and helps regulate processes such as brain development. So it’s no surprise scientists from the Seattle Children’s Research Institute found higher levels of a mom’s vitamin D level during pregnancy correlated to greater childhood IQ scores.
While this observational study does not prove causation, researchers believe the findings they published in the Journal of Nutrition have important implications and should be examined further.
Study author Melissa Melough and her colleagues used data from the Tennessee CANDLE study (Conditions Affecting Neurocognitive Development and Learning in Early Childhood). The study focused on pregnant women and collected information over time related to the health and development of their children. Researchers discovered the higher the vitamin D levels during pregnancy the higher the IQ scores between the ages of 4 and 6.
"Vitamin D deficiency is quite prevalent," Melough said. "The good news is there is a relatively easy solution. It can be difficult to get adequate vitamin D through diet, and not everyone can make up for this gap through sun exposure, so a good solution is to take a supplement."
Melough saw many in the study low in vitamin D but was especially troubled by the high rate of deficiency she saw among black women. She estimates as many as 80 percent of black pregnant women may be deficient in vitamin D.
"Melanin pigment protects the skin against sun damage, but by blocking UV rays, melanin also reduces vitamin D production in the skin,” Melough said. “Because of this, we weren't surprised to see high rates of vitamin D deficiency among Black pregnant women in our study.”
Melough went on to say, "I want people to know that it's a common problem and can affect a child's development. Vitamin D deficiency can occur even if you eat a healthy diet. Sometimes it's related to our lifestyles, skin pigmentation or other factors outside of our control."
Researchers use the conservative figure of 600 IU as the recommended daily intake of vitamin D and say Americans on average consume less than 200 IU in their diet so the rest needs to be made up through sun exposure and supplementation. Missing the daily intake target for an extended period of time can lead to a serious deficiency.
“Even though many pregnant women take a prenatal vitamin, this may not correct an existing vitamin D deficiency," Melough said. "I hope our work brings greater awareness to this problem, shows the long-lasting implications of prenatal vitamin D for the child and their neurocognitive development, and highlights that there are certain groups providers should be paying closer attention to. Wide-spread testing of vitamin D levels is not generally recommended, but I think health care providers should be looking out for those who are at higher risk, including black women."