Vitamin D is a critical nutrient and has many important functions in the body. Photo credit: Seattle Children’s
Vitamin D is a critical nutrient and has many important functions in the body. A mother’s supply of vitamin D is passed on to her baby in the uterus and helps regulate processes, including brain development. A study published on November 2, 2020 in The Journal of Nutrition showed that maternal vitamin D levels during pregnancy were associated with their children’s IQ, suggesting that higher levels of vitamin D during pregnancy may lead to higher IQ scores in children. The study also identified significantly lower vitamin D levels in black pregnant women.
Melissa Melough, lead author of the study and a researcher in the Department of Child Health, Behavior and Development at Seattle Children’s Research Institute, says vitamin D deficiency is common in both the general population and pregnant women, but notes that black women are at higher risk. Melough hopes the study will help health care providers eliminate the differences between women with skin color and women at higher risk of vitamin D deficiency.
“Melanin pigment protects the skin from sun damage, but by blocking UV rays, melanin also reduces vitamin D production in the skin. For this reason, we were not surprised to find high levels of vitamin D deficiency in black pregnant women in our study. Although many pregnant women take a prenatal vitamin, it may not correct an existing vitamin D deficiency, ”Melough said. “I hope our work will create greater awareness of this issue, show the long-term effects of prenatal vitamin D on the child and their neurocognitive development, and highlight that there are certain groups that providers should pay more attention to. Extensive testing of vitamin D levels is generally not recommended, but I think healthcare providers should be on the lookout for those at higher risk, including black women. ”
Eliminate inequalities
According to Melough, up to 80% of black pregnant women in the US may be deficient in vitamin D. Of the women who participated in the study, approximately 46% of mothers were deficient in vitamin D and vitamin D during their pregnancy black women had lower values than white women.
Melough and her co-authors used data from a cohort in Tennessee called the Study on the Effects of Neurocognitive Development and Learning in Early Childhood (CANDLE). CANDLE researchers recruited pregnant women to participate in the study from 2006 onwards and, over time, gathered information about their children’s health and development.
After controlling for several other factors related to IQ, higher levels of vitamin D during pregnancy were associated with higher IQ in children 4-6 years of age. Although observational studies like this one cannot demonstrate a cause, Melough believes their results have important implications and warrant further research.
Lack of vitamin D.
“Vitamin D deficiency is common,” Melough said. “The good news is that there is a relatively simple solution. Getting enough vitamin D through diet can be difficult, and not everyone can make up for this gap with sun exposure. A good solution is therefore to take a dietary supplement. ”
The recommended daily intake of vitamin D is 600 international units (IU). On average, Americans use less than 200 IU in their diet. If people don’t fill that void with sun exposure or supplementation, people are likely to become deficient, according to Melough. Foods that are higher in vitamin D include fatty fish, eggs, and fortified sources like cow’s milk and breakfast cereals. However, Melough notes that vitamin D is one of the most difficult nutrients to get from our diet in sufficient quantities.
Additional research is needed to determine optimal vitamin D levels during pregnancy. However, Melough hopes this study will help develop dietary recommendations for pregnant women. Especially for black women and those at high risk of vitamin D deficiency, dietary supplements and health screening can be an effective strategy for reducing health inequalities.
The central theses
Melough says there are three key takeaways from the study:
- Vitamin D deficiency is common during pregnancy, and black women are at greater risk because melanin pigments in the skin reduce the production of vitamin D.
- Higher levels of vitamin D in mothers during pregnancy can promote brain development and lead to higher IQ scores in children
- Screening and nutritional supplementation can correct vitamin D deficiency in people at risk and promote cognitive function in the offspring
“I want people to know that this is a common problem and that it can affect children’s development,” Melough said. “Vitamin D deficiency can occur even if you eat healthily. Sometimes it’s related to our lifestyle, skin pigmentation, or other factors that are beyond our control. ”
Reference: “Maternal Plasma 25-Hydroxyvitamin D During Pregnancy Is Positively Associated with Neurocognitive Development in Offspring Aged 4 to 6 Years” by Melissa M. Melough, Laura E. Murphy, J. Carolyn Graff, Karen J. Derefinko, Kaja Z. LeWinn, Nicole R. Bush Daniel A. Enquobahrie, Christine T. Loftus, Mehmet Kocak, Sheela Sathyanarayana and Frances A. Tylavsky, November 2, 2020, The Journal of Nutrition.
DOI: 10.1093 / jn / nxaa309
