How (in)effective are Vitamin D supplements in children? Biggest-ever clinical trial finds out

The widespread belief that Vitamin D supplements can help prevent bone fractures in children has been challenged after a clinical trial found that this is not true. According to a research published in the journal Lancet Diabetes and Endocrinology, even if a child has a Vitamin D deficiency, the supplements do not increase bone strength or prevent bone fractures. 

How the study was conducted?

The study, conducted in Mongolia, involved 8,851 schoolchildren aged 6 to 13 with 95.5 per cent having a vitamin D deficiency. Over three years, the children received weekly vitamin D doses, resulting in clinically normal vitamin D levels. 

Scientists found no change in fracture risk or increased bone strength.

"The absence of any effect of sustained, generous vitamin D supplementation on fracture risk or bone strength in vitamin D-deficient children is striking," Ganmaa Davaasambuu, associate professor at the Harvard T.H. Chan School of Public Health, said in a statement.

Notably, the research excluded children with rickets, a condition resulting from severe and prolonged vitamin D deficiency. 

The findings, therefore, specifically apply to those without rickets.

What does it mean?

The study underscores the necessity for continued research and nuanced approaches to addressing vitamin D deficiency and its impact on childhood bone health.

Since these results have emerged from a randomised clinical trial, the findings hold clinical relevance. 

Some experts, such as Nick Bishop from the University of Sheffield, however, questioned the methodology's reliance on ultrasound for assessing bone strength.

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"The study is very thorough in its design and execution although I don't think that the use of ultrasound to assess 'bone strength' is a widely accepted methodology; speed of sound will reflect bone size and so vary progressively with age," Bishop said in a statement.

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But there still remains the need to promote vitamin D supplements and fortified foods, particularly during winters when sunlight-derived vitamin D is limited.

What is the bottom line? 

The conventional wisdom about the role of vitamin D supplements in bone health during childhood now stands clinically disputed.

(With inputs from agencies)