"Vitamin D supplementation of pregnant women, especially during winter months, could lead to longstanding reductions in the risk of osteoporotic fracture in their offspring," conclude the authors of the new research, published in tomorrow's issue of The Lancet (vol 367, No. 9504, pp 36-43).
The study, by a team at the University of Southampton in the UK, is the latest in a series of reports showing the role of this vitamin in protecting bones and against serious disease.
Yet many people in the northern hemisphere are deficient in the vitamin, which is made largely through exposure to sunshine.
The new results will therefore reinforce calls for supplementation of the diet, which only contains low amounts of the vitamin in milk, fish, liver and egg yolk.
The longitudinal study followed 198 children up to nine years of age. The vitamin D levels of the mothers were recorded during pregnancy and related to the child's body mass and bone density.
During pregnancy, 31 per cent of the mothers had 'insufficient' vitamin D levels, while a further 18 per cent were classified as 'deficient'.
The children of vitamin-deficient mothers had an average whole-body bone mineral content (BMC) of 1.04 kg compared to a BMC of 1.16 kg for children from mothers with sufficient vitamin D levels.
The same trend was also observed for lumbar-spine BMC.
"Our study provides direct evidence that the intrauterine environment, as indicated by maternal vitamin D status during pregnancy, is significantly correlated with bone-mineral accrual at age 9 years," claimed the researchers.
Vitamin D is known to promote calcium and phosphate absorption from food and is essential in tooth and bone formation. But the new research shows the importance of bone health from the very start of life.
Jackie Parrington, spokeswoman for the British charity the National Osteoporosis Society, told NutraIngredients.com: "This is very important research because it shows that looking after your bones starts at a much earlier age in a child's development than most people would have thought."
The research comes hot on the heels of other reports inversely linking vitamin D consumption to reduced risk of certain cancers. Tesco, Britain's largest supermarket chain, has recorded a 400 per cent increase in vitamin D supplement sales since late December.
The European and US recommended daily intake (RDI) of vitamin D is 5 micrograms (200 International Units). A recent study in the American Journal of Public Health called for a change of the RDI to 25 micrograms (1000 IU).