Researchers studied whether a mother’s low vitamin D during pregnancy and breastfeeding could affect how her babies’ brains develop. Using mice, they found that mothers with very low vitamin D had offspring that showed autism-like behaviors, including difficulty with social interactions and repetitive actions. The scientists discovered that low vitamin D may change how brain cells grow and communicate. While this is early research in animals, it suggests that maintaining healthy vitamin D levels during pregnancy and nursing might be important for brain development. More research in humans is needed to confirm these findings.

The Quick Take

  • What they studied: Whether mothers with very low vitamin D levels have babies that show autism-like behaviors and what happens in the baby’s brain to cause this
  • Who participated: Female mice were given a diet with no vitamin D from young adulthood through pregnancy and nursing. Their offspring were then observed for behavioral changes
  • Key finding: Baby mice born to vitamin D-deficient mothers showed more autism-like behaviors, including difficulty socializing and repetitive actions. The researchers found changes in how brain cells were growing and communicating
  • What it means for you: This animal study suggests that pregnant women and nursing mothers should maintain adequate vitamin D levels, though human studies are still needed to confirm this connection. Talk to your doctor about vitamin D screening during pregnancy

The Research Details

This was an animal study using mice to understand how vitamin D deficiency might affect brain development. Researchers created a group of mice with very low vitamin D by feeding them a special diet starting when they were young adults, continuing through pregnancy and nursing. They then watched the baby mice to see if they showed behaviors similar to autism in humans, like difficulty interacting with other mice and repetitive actions.

The scientists also examined the babies’ brains under a microscope to see what was happening at the cellular level. They looked for specific markers that show how brain cells are growing and dividing, and they studied a particular pathway in the brain that’s important for development called the WNT/β-catenin pathway.

This type of study is important because it allows researchers to carefully control conditions and examine brain tissue directly, which can’t be done in humans. However, findings in mice don’t always translate directly to humans.

Animal studies like this help scientists understand the biological mechanisms—the ‘how’ and ‘why’—behind potential health connections. By studying mice, researchers can examine brain tissue and control variables precisely. This groundwork is necessary before conducting human studies, which are more complex and expensive

This is a controlled laboratory study, which is good for understanding mechanisms. However, the sample size wasn’t specified in the abstract, making it difficult to assess statistical power. The study was conducted in mice, so results may not directly apply to humans. The research was published in a peer-reviewed journal, which means other scientists reviewed it before publication. Additional human studies would be needed to confirm these findings apply to people

What the Results Show

Baby mice born to mothers with severe vitamin D deficiency showed several autism-like behaviors. Both male and female offspring had difficulty with social interactions compared to babies from mothers with normal vitamin D. Female offspring showed increased repetitive behaviors, such as burying more marbles (a test used to measure obsessive-like behavior in mice).

When researchers examined the babies’ brains, they found that cells were dividing and multiplying more than normal. They also found increased numbers of intermediate progenitor cells, which are important for building the brain’s outer layer (cerebral cortex). These changes suggest that vitamin D deficiency may disrupt the normal pattern of brain cell development.

The researchers identified a specific biological pathway that appeared to be affected: the WNT/β-catenin pathway, which is crucial for brain development. In vitamin D-deficient fetuses, a protein called DKK1 (which blocks this pathway) was increased, while β-catenin (which activates the pathway) was decreased. This imbalance may explain why brain development was disrupted.

The study also observed anxiety-like behaviors in the offspring, though this wasn’t the main focus. The changes in brain cell development were most pronounced in the cerebral cortex, the brain’s outer layer responsible for complex functions like social behavior and learning. The effects appeared in both male and female offspring, though some behaviors were more pronounced in females

Previous studies in humans have suggested a link between low maternal vitamin D and autism risk, but the exact mechanism wasn’t understood. This animal study provides a potential explanation by showing how vitamin D deficiency might disrupt a specific brain development pathway. However, human studies have shown mixed results, and vitamin D is just one of many factors that may influence autism risk. This research adds to growing evidence that vitamin D plays a role in brain development, but doesn’t prove it’s a cause of autism

This study was conducted in mice, not humans, so results may not directly apply to people. The abstract doesn’t specify how many mice were studied, making it hard to assess the strength of the findings. The study created extreme vitamin D deficiency, which may be more severe than what occurs in most human pregnancies. The research shows correlation and a potential mechanism, but doesn’t prove that vitamin D deficiency causes autism. Other factors affecting autism risk weren’t examined in this study

The Bottom Line

Based on this animal research, maintaining adequate vitamin D levels during pregnancy and nursing appears important for fetal brain development. Current medical guidelines recommend pregnant and nursing women get 600-800 IU of vitamin D daily, though some experts suggest higher amounts. Discuss vitamin D screening and supplementation with your healthcare provider, especially if you’re planning pregnancy, currently pregnant, or nursing. This recommendation has moderate confidence based on animal evidence and some human epidemiological studies, but more human research is needed

Pregnant women, women planning pregnancy, and nursing mothers should be most interested in this research. Women with limited sun exposure, darker skin tones, or dietary restrictions may be at higher risk for vitamin D deficiency. Healthcare providers caring for pregnant and postpartum women should consider this research when counseling about prenatal nutrition. This research is less directly relevant to people who aren’t pregnant or nursing, though adequate vitamin D is important for everyone’s health

If vitamin D deficiency affects brain development, the critical period appears to be during pregnancy and early nursing, based on this study. The effects on behavior were observable in the offspring after birth. If a pregnant woman corrects vitamin D deficiency, benefits would likely need to occur during pregnancy to affect fetal brain development. There’s no evidence that correcting vitamin D deficiency after birth would reverse autism-like behaviors

Want to Apply This Research?

  • If pregnant or nursing, track daily vitamin D intake (from food, supplements, and sun exposure) and note any vitamin D blood test results. Set a goal of meeting recommended daily intake and log weekly compliance
  • Users can set a daily reminder to take a vitamin D supplement if recommended by their doctor, log their supplement intake, and track sun exposure time. Users can also log dietary sources of vitamin D like fortified milk, fatty fish, and egg yolks
  • For pregnant and nursing women, track vitamin D supplementation consistency monthly. Record any vitamin D blood test results from healthcare visits. Note any changes in mood or energy levels, which can be affected by vitamin D status. Share tracking data with healthcare provider at prenatal and postpartum appointments

This research is based on animal studies in mice and does not prove that vitamin D deficiency causes autism in humans. While the findings are interesting, they should not be used to diagnose, treat, or prevent autism or any other condition. Pregnant women, women planning pregnancy, and nursing mothers should consult with their healthcare provider about appropriate vitamin D levels and supplementation. This information is for educational purposes only and is not a substitute for professional medical advice. Autism spectrum disorder is complex and involves many genetic and environmental factors beyond vitamin D status.