The value of optimal vitamin D levels in the body cannot be emphasized enough, especially among pregnant women. In a Finnish study, the risk of attention deficit hyperactivity disorder (ADHD) was 34% greater in children whose mother suffered from a vitamin D deficiency during pregnancy, compared to those whose mother’s vitamin D status was sufficient in the first and second trimesters
Vitamin D deficiency has been linked to wide-ranging health consequences, from dementia and cognitive impairment to the occurrence of various types of cancers. About 1 billion people worldwide have vitamin D deficiency, while half of the population suffer from insufficiency in the “sunshine nutrient.”[i]
Contrary to conventional advice, sun exposure then takes on great value and significance considering the new data emerging on vitamin D‘s importance. A mountain of studies can vouch for the benefits of vitamin D, including in the area of maternal health and child nutrition.
In Finland, a nationwide population-based case control study covering 1,067 attention deficit hyperactivity disorder (ADHD) cases found a higher risk for ADHD in children whose mother was vitamin D deficient during pregnancy.[ii]
It was, in fact, the first population-level study to show the link between low maternal vitamin D level in early to middle pregnancy stages and an increased risk for diagnosed ADHD in the baby.
Low Vitamin D During Pregnancy Linked to ADHD Risk in Baby
In the study, the Finnish registry identified 1,067 children with ADHD — born from 1998 to 1999 and diagnosed according to International Classification of Diseases standards — and 1,067 matched controls. The data was collected prior to the current recommendation in the country for vitamin D intake during pregnancy, which is 10 micrograms (400 IU) a day throughout the year.
Adjusting for maternal age and socioeconomic status as well as psychiatric history, the researchers found a 34% higher risk for ADHD in offspring whose mother was vitamin D deficient versus those who had a sufficient level in the first and second trimesters of pregnancy.
Dr. Minna Sucksdorff from the University of Turku in Finland, whose group collaborated with researchers from Columbia University in New York, said in a statement[iii] that alongside genotype, prenatal factors such as vitamin D deficiency while pregnant can influence the development of ADHD.
Millions of children in the U.S. have been diagnosed with ADHD. According to a 2016 parent survey, 6.1 million, or 9.4%, of children have the condition, with a staggering 4 million of them aged 6 to 11 years.[iv]
Controversial Vitamin D Recommendations
Back in 2011, a controversial report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine (IOM) found bone health to be the only area of benefit.[v] The committee also recommended only 600 IU per day of vitamin D and a serum 25(OH)D concentration — a precursor to the active vitamin D form — of 20 ng/ml or 50 nmol/l for people ages 1 to 70 years, and 800 IU per day for those at least 71 years old.
The vitamin D research community, however, was quick to disagree with the official recommendations, citing the very low recommended dose of the nutrient as a failure “in a major way on logic, on science, and on effective public health guidance.”[vi]
Global Epidemic of Deficiency
As ADHD emerges as one of the most prevalent chronic conditions among children, the study results may have great significance for public health, according to primary investigator professor Andre Sourander.[vii] He pointed to vitamin D deficiency as a global problem, where the intake among mothers in several immigrant groups, for instance, languish at an insufficient level.
A previous study demonstrated that the effects of vitamin D during fetal development are mostly mediated through the active form of vitamin D called 1,25-dihydroxyvitamin D binding to vitamin D receptors.[viii] This then regulates the expression of more than 200 genes, specifically upregulating some two-thirds and downregulating the remaining one-third.
Estimates from a population study for the world’s six geopolitical regions pinpointed a reduction in all-cause mortality rates from higher mean serum 25(OH)D concentrations.[ix] Included in their calculations are relationships between serum 25(OH)D and disease outcomes for conditions such as:
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