Vitamin D is a critical nutrient and has many important functions in the body. A pregnant woman’s vitamin D supply is passed to her baby in the womb via the placenta and helps to regulate processes including brain development. A number of studies show that vitamin D levels during pregnancy can affect the health of the child, so it is important for expectant mothers to ensure adequate levels.
Vitamin D Levels and Child IQ
A study published in the Journal of Nutrition shows that mothers’ vitamin D levels during pregnancy are linked to their children’s IQ, suggesting that higher vitamin D levels during pregnancy contribute to higher IQ scores in the children. The study also identified significantly lower vitamin D levels in black pregnant women.
Melissa Melough, the lead author of the study and a research scientist in the Division of Child Health, Behavior and Development at the Seattle Children’s Research Institute, explains that vitamin D deficiency is common in both the general population and pregnant women, albeit black women are more at risk. Melanin pigment protects the skin from sun damage, but by blocking UV rays, melanin also reduces vitamin D production in the skin. Because of this, the researchers weren’t surprised to see greater vitamin D deficiency in pregnant black women in the study.
Melough and her co-authors used data from a Tennessee cohort called the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) study. CANDLE researchers recruited pregnant women to take part in the study beginning in 2006 and collected information about their children’s health and development over time. After accounting for several other factors related to IQ, higher levels of vitamin D in pregnancy were associated with higher IQ in children aged 4 to 6 years. Although observational studies like these cannot prove causality, the scientists believe their findings have important implications and warrant further research.
Vitamin D Reduces the Risk of Childhood Eczema
According to a study by researchers at the University of Southampton, taking vitamin D supplements during pregnancy could significantly reduce the chances of babies up to a year old developing atopic eczema. The study, published in the British Journal of Dermatology, found that babies had a reduced risk of developing atopic eczema in their first year if their mothers took 1,000 international units of vitamin D from 14 weeks’ gestation until birth.
Atopic eczema is a chronic inflammatory disease that can have a major impact on sufferers, their families and public health. It is estimated that one in six children aged one to five years suffers from it. The study, from the Lifecourse Epidemiology Center of the University of Southampton Medical Research Council and the NIHR Southampton Biomedical Research Center, is the first randomized controlled trial to show evidence of a reduced risk of atopic eczema in infants born to mothers who took vitamin D supplements during pregnancy.
More than 700 pregnant women took part in the study – 352 took the supplements from week 14 until delivery, 351 took a placebo. The results showed that babies born to mothers who received supplements had a reduced risk of developing atopic eczema at 12 months, supporting recommendations for routine vitamin D supplements during pregnancy. Breastfed infants benefit even more. This could indicate that supplementation during pregnancy increases the amount of vitamin D in breast milk.
Vitamin D and ADHD
A mother’s vitamin D levels may also be linked to a child’s risk of ADHD, according to research. Research from Finland showed that children whose mothers had vitamin D deficiency during pregnancy had a 34 percent higher risk of ADHD than children whose mothers had adequate vitamin D levels in the first and second trimester. In addition to the genotype, prenatal factors such as vitamin D deficiency during pregnancy can therefore influence the development of ADHD.
The study included 1,067 children born between 1998 and 1999 diagnosed with ADHD in Finland and an equal number of matched controls. The data were collected prior to the current national recommendation in Finland for vitamin D intake during pregnancy, which is 10 micrograms per day throughout the year. Lead researcher, Professor Andre Sourander, says vitamin D deficiency is still a global problem despite recommendations. In Finland, for example, maternal vitamin D intake is insufficient in several immigrant groups.
This research provides strong evidence that low vitamin D levels during pregnancy are associated with lack of attention in the offspring. Since ADHD is one of the most common chronic diseases in children, the research results have important public health implications. The study is part of a larger research project aimed at uncovering the links between maternal health during pregnancy and ADHD in offspring. The aim is to obtain information to develop preventive treatments and measures to identify children at risk of ADHD.
According to research, low maternal vitamin D levels during pregnancy can also affect milk tooth calcification and lead to enamel defects, which are a risk factor for early childhood tooth decay. Since it is often difficult to get enough vitamin D from the daily diet alone, a dietary supplement can be recommended. The recommended daily dose of vitamin D is 600 International Units (IU). Foods higher in vitamin D include oily fish, eggs, and fortified sources like cow’s milk and breakfast cereals.