Strong bones are something that benefit a child as they grow up and ensuring they have them can actually be done before they are born. Building on a study that showed similar results at age four, researchers at the University of Southampton in England found children whose mothers were given vitamin D supplementation during pregnancy had healthier bones at age 7 compared to their peers whose mothers did not take vitamin D.

This randomized, controlled trial used bone density scans to measure the impact of vitamin D supplementation for pregnant women on their children and the results were published in the American Journal of Clinical Nutrition. The scans showed the bones of the women who took supplements contained more calcium and other minerals which made them stronger and less susceptible to breaking.

The study was a review of data from the MAVIDOS (Maternal Vitamin D Osteoporosis Study) study which began in 2009 with 1,000 women in England. They were assigned to one of two groups: one received 1,000 International Units of vitamin D per day and the other was given a placebo. Neither the participants or their caregivers knew to which group they were assigned.

Vitamin D regulates the amount of calcium and phosphate in the body and is necessary for the development of strong bones and teeth.

"Our findings show that the benefits of vitamin D supplementation during pregnancy persist into mid-childhood," said Dr. Rebecca Moon. "This early intervention represents an important public health strategy. It strengthens children's bones and reduces the risk of conditions like osteoporosis and fractures in later life."

Previous research showed that at the age of four, the children whose mothers were given vitamin D had healthier bones. This confirms the benefits continued for at least three more years.

"These findings add to the important knowledge generated through the MAVIDOS trial," said Professor Nicholas Harvey. "We extend our heartfelt thanks to all the mothers and children involved. Their contributions have advanced our understanding of vitamin D supplementation and its role in supporting strong and healthy bones."

Click here to read more in the American Journal of Clinical Nutrition.