Babies and small children are less likely to develop croup if their mothers have taken high-dosed vitamin D and fish oil during their pregnancy, according to a Danish study, where scientists have studied this relation for the very first time. Vitamin D and fish oil also benefit the child’s immune defense and counteract the inflammation in the respiratory system that triggers croup. The two supplements even have a positive impact on the child’s bone health and nervous system, and they also help prevent asthma.
Croup typically affects babies and children younger than five years of age. The condition often starts off as a cold or other type of respiratory tract infection that causes swelling of the area of the vocal cords. The most typical symptoms are breathing difficulty and a cough that resembles the bark of a sea lion. Croup typically occurs at night after a brief period of sleep and normally has a mild course. In severe cases, however, the child may need to be hospitalized because the breathing difficulty requires intensive care.
There is no effective vaccine against croup. Therefore, a team of scientists from Copenhagen University Hospital wanted to study if supplementation with vitamin D and fish oil could somehow give the immune system a boost.
The cohort study is named COPSAC (Copenhagen Prospective Studies on Asthma in Childhood) and includes 736 pregnant women and their offspring. Each woman was randomly assigned to one of the four following regimens:
- High-dosed vitamin D (70 micrograms) and fish oil (2.4 grams)
- High-dosed vitamin D (70 micrograms) and olive oil
- Standard-dosed vitamin D for pregnant women (10 micrograms) and fish oil (2.4 grams)
- Standard-dosed vitamin D for pregnant women (10 micrograms) and olive oil
High-dosed vitamin D and fish oil counteract croup
All the pregnant women took their assigned regimen, starting at the 24th week of pregnancy and continuing until a week after childbirth. Neither the women nor the scientists knew who got what. This was not disclosed until after the study had been terminated.
While the study was ongoing, the scientists examined the children until three years of age. Ninety-seven percent of the children developed croup, and the study showed that:
- Children whose mothers had taken fish oil had a 38 percent lower risk of developing croup compared with children whose mothers had taken olive oil
- Children whose mothers had taken high-dosed vitamin D (70 micrograms) had a 40 percent lower risk of developing croup compared with children of mothers who had taken the 10-microgram dose of vitamin D
The scientists believe that high-dosed vitamin D and fish oil taken during pregnancy may be effective for preventing childhood croup.
How does vitamin D and fish oil prevent croup?
The researchers do not know the specific mechanisms but assume that vitamin D and fish oil stimulate the children’s immune systems. It is also likely that the two supplements counteract unwanted inflammation of the vocal cord mucosa.
Other benefits of taking high-doses vitamin D and fish oil
The scientists have already looked into other health benefits of maternal supplementation with vitamin D and fish oil during pregnancy. This includes the positive impact on the child’s bone health, central nervous system, body structure, and prevention of asthma. If the expecting mother smokes, it may impair the pulmonary function of her child. There is also increasing focus on the mother’s diet and how it can affect the health of the child’s respiratory tract. The scientists therefore call for additional studies, and with the emerging science in this area, health authorities may have to issue new guidelines for supplementation during pregnancy, especially with regard to vitamin D and fish oil.
Emily Henderson. Study investigates the effect of vitamin D and fish oil on croup. News Medical Life Sciences. Sep. 5 2022.
Jose Luis Mansur et al. Vitamin D: Before, during and after Pregnancy: Effect on Neonates and Children. Nutrients. 2022
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