Researchers in India studied 277 children to understand why so many don’t have enough vitamin D in their blood, even though India gets plenty of sunshine. They found that 78% of children had low vitamin D levels. The study discovered that the amount of time kids spend in the sun, whether they use sunscreen, and what they eat all play important roles. Kids who spent more than 2 hours in the sun daily had much better vitamin D levels, while those who used sunscreen had lower levels. Eating milk and eggs regularly also helped boost vitamin D. These findings suggest that simple changes to sun exposure, diet, and possibly vitamin D supplements could help more children stay healthy.

The Quick Take

  • What they studied: How many children in India have low vitamin D levels and what causes it, even though India has lots of sunshine
  • Who participated: 277 healthy children between 9 months and 12 years old visiting a hospital in western India. About 56% were boys, and they came from different family backgrounds and income levels
  • Key finding: About 3 out of 4 children (78%) had vitamin D levels that were too low. Kids who spent more than 2 hours outside daily had much better vitamin D levels (73% had enough) compared to those with less sun time (only 9% had enough)
  • What it means for you: If you have children, encouraging them to spend time outdoors, limiting sunscreen use (while still protecting from burns), and making sure they eat milk and eggs may help them get enough vitamin D. However, this study shows what’s connected to vitamin D levels—it doesn’t prove that changing these things will definitely fix the problem

The Research Details

Researchers visited a children’s hospital in western India and enrolled every fourth child who came in for vaccinations or came with a healthy sibling between April 2023 and June 2025. They asked parents questions about how much time their children spent in the sun, whether they used sunscreen, what foods they ate, and their family’s income level. Then they took a small blood sample from each child to measure their vitamin D levels using a laboratory test.

The researchers used official guidelines to decide if each child had enough vitamin D (30 or higher), not quite enough (20-29), or too little (below 20). They then looked for patterns—for example, did kids who spent more time in the sun have better vitamin D levels? Did eating certain foods make a difference?

This type of study is useful for understanding what factors are connected to vitamin D levels in real children living their normal lives. By looking at many children at once and comparing their habits and blood test results, researchers can spot patterns that might help doctors and parents make better choices. However, this study design can show what’s connected but can’t prove that one thing causes another.

This study has several strengths: it included a decent number of children (277), used a proper laboratory test to measure vitamin D, and asked detailed questions about sun exposure and diet. However, the study only looked at children visiting one hospital in one part of India, so the results might not apply to all Indian children or children in other countries. The researchers couldn’t prove that sun exposure causes better vitamin D levels—only that they’re connected. Also, parents answered questions about their children’s habits from memory, which might not always be perfectly accurate.

What the Results Show

The study found that vitamin D deficiency is very common among Indian children. Out of 277 children studied, about 1 in 3 (34.7%) had dangerously low vitamin D levels, and another 43% had levels that were lower than ideal. Only about 1 in 4 children (22.4%) had healthy vitamin D levels.

The biggest difference came down to sun exposure. Children who spent more than 2 hours per day in the sun had much better vitamin D levels—about 73% of them had healthy levels. In contrast, only 9% of children with less sun exposure had healthy vitamin D levels. This huge difference shows that time in the sun is very important for vitamin D.

Interestingly, using sunscreen was connected to lower vitamin D levels. Children who used sunscreen had a 50% deficiency rate, while those who didn’t use sunscreen had a 32% deficiency rate. This makes sense because sunscreen blocks the sun’s rays that help your body make vitamin D, though sunscreen is still important for preventing skin damage.

Food choices also mattered. Children who drank milk regularly had better vitamin D levels than those who didn’t. Kids who ate eggs 3-5 days per week had the best vitamin D levels, while those who ate eggs less often or more often had lower levels.

The study looked at whether age, gender, religion, or family income level affected vitamin D status. Surprisingly, none of these factors made a significant difference. Boys and girls had similar vitamin D levels. Younger and older children in the study had similar levels. However, there was a slight trend suggesting that children from wealthier families might have had lower vitamin D levels, though this wasn’t statistically proven. This unexpected finding might be because wealthier families use more sunscreen or keep children indoors more often.

This research confirms what other studies have found: vitamin D deficiency is a major problem in India despite the country’s sunny climate. Previous research has shown similar patterns in other parts of India and other sunny countries. This study adds new details by showing exactly how much sun exposure matters (more than 2 hours daily makes a big difference) and how specific foods like eggs and milk help. The finding that sunscreen use is connected to lower vitamin D levels is important because it shows a trade-off between protecting skin from damage and allowing the body to make vitamin D.

This study has several limitations to keep in mind. First, it only included children from one hospital in western India, so the results might be different in other parts of India or other countries. Second, the study asked parents to remember and report their children’s habits, which might not always be accurate. Third, the study only measured vitamin D levels at one point in time, so we don’t know if these patterns stay the same throughout the year or over many years. Fourth, the study shows what’s connected to vitamin D levels but can’t prove that one thing causes another—for example, we can’t say for certain that more sun exposure causes better vitamin D levels, only that they’re related. Finally, the study didn’t look at whether children had any health problems related to low vitamin D, so we don’t know if the low levels actually caused health issues.

The Bottom Line

Based on this research, here are practical steps parents can consider: (1) Encourage children to spend at least 2 hours per day outdoors in sunlight, which appears to be the level needed for good vitamin D levels. (2) Make sure children eat milk regularly and eat eggs several times per week, as these foods are connected to better vitamin D status. (3) Use sunscreen carefully—balance sun protection with allowing some sun exposure for vitamin D production. (4) Talk to your doctor about whether your child needs a vitamin D supplement, especially if they can’t get enough sun exposure or eat enough vitamin D-rich foods. These recommendations have moderate confidence because the study shows connections but doesn’t prove cause-and-effect.

Parents of children aged 9 months to 12 years should pay attention to these findings, especially if they live in India or other sunny climates. Children who spend most of their time indoors, use sunscreen regularly, or eat limited dairy and eggs may be at higher risk for low vitamin D. However, these findings may not apply as strongly to children in less sunny climates or those with different diets. If your child has health conditions affecting bone health, digestive problems, or limited sun exposure, talk to your doctor about vitamin D testing and supplementation.

If you make changes based on these findings—like increasing outdoor time or adding more milk and eggs to your child’s diet—you probably won’t see immediate results. Vitamin D builds up in the body over weeks and months. It typically takes 4-8 weeks of consistent changes to see meaningful improvements in blood vitamin D levels. If your doctor recommends a vitamin D supplement, it may work faster, but you’d still need to take it regularly for several weeks to see results.

Want to Apply This Research?

  • Track daily outdoor time in minutes (target: 120+ minutes per day) and record which days your child eats milk or eggs. Use the app to set reminders for outdoor play and meal planning with vitamin D-rich foods.
  • Set a daily goal of 2+ hours of outdoor play time. Create a simple food tracker to monitor milk intake (daily) and egg consumption (3-5 times per week). Use app notifications to remind you to include these foods in meals and to encourage outdoor activities.
  • Check in weekly on outdoor time and food intake. After 6-8 weeks of consistent changes, work with your doctor to retest vitamin D levels if they were previously low. Track seasonal changes in outdoor time and adjust strategies accordingly, as sun exposure may vary by season.

This research shows connections between certain habits and vitamin D levels in children, but it cannot prove that changing these habits will definitely improve your child’s vitamin D status or prevent health problems. Vitamin D needs vary by age, skin tone, location, and individual health conditions. Before making significant changes to your child’s sun exposure, sunscreen use, or diet, or before starting any supplements, please consult with your pediatrician or a registered dietitian. This information is educational and should not replace professional medical advice. If you suspect your child has a vitamin D deficiency, ask your doctor about blood testing and personalized treatment recommendations.