Sun exposure good for fetus' bones

Women who get some sun during the last trimester of pregnancy have children with stronger bones. Milk and breakfast cereals fortified with vitamin D are among the main food sources of the vitamin. Few foods naturally contain vitamin D, though some fish, like salmon, mackerel and tuna, contain substantial amounts. Currently, the official recommendation for vitamin D during pregnancy is 200 IU per day, though researchers are still trying to determine what the optimal intake is. A number of studies have suggested that vitamin D deficiency is common in pregnant women. Few studies in the past have examined the association between vitamin D exposure of pregnant women and skeletal development of the child. To explore this association, researchers from Britain studied 995 boys and girls, aged around 10 years. The participants underwent bone scans and the researchers used local meteorological data to estimate the mothers' UV (Ultra violet rays) exposure during their last trimester. It was found that children whose mothers had greater sun exposure tended to have larger bones than those whose mothers had less sun exposure. It was concluded that maternal UVB exposure is related to bone size independently of height and lean mass, suggesting that vitamin D status in pregnancy exerts direct effects on bone formation in subsequent childhood. The above findings were attributed to the fact that vitamin D gets synthesised in the skin after sun exposure and plays a key role in bone health. The results offer further justification for strategies intended to improve maternal vitamin D status to optimise skeletal health the child. The researchers, however, warned against over exposure to sun during pregnancy, as it is a known risk factor for skin cancer.

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