Sufficient Vitamin D during the second trimester of pregnancy could help reduce a child's risk of developing asthma says a new American study.
Carried out by the University of Kansas, the team of researchers used data taken from hospital discharges in two US states and a national health survey (full sample of 595,093) to look at when and where in the country asthmatics were born.
By measuring the levels of sunlight in these locations when the asthmatics' mothers would have been in their second trimester of pregnancy, the team found that a woman with a higher level of exposure to sunlight during this time, and therefore a higher level of vitamin D, lowered her baby's chance of developing asthma.
And the location wasn't the only factor in how much sunlight you received. "We're not looking at sunny places versus non-sunny places," said David Slusky, one of the study's co-authors, "We looked at the relative differences of the level of sunlight at a particular place at a particular time of year."
Meaning that women in Georgia who were in the their second trimester of pregnancy in July of 1978 were exposed to a different level of sunlight than pregnant women in Georgia a year later. "If that place is relatively more sunny during the second trimester, we found relatively lower rates of asthma," Slusky said.
In fact the findings showed that as little as 10 minutes of sunshine a day for pregnant women could be enough to help, with previous medical findings also suggesting that this is all most of us need for a daily dose of vitamin D, dubbed "the sunshine vitamin."
Americans receive more than 90 percent of their vitamin D from exposure to sunlight, however many people are still concerned about the risks of too much sun exposure, which could affect the amount of vitamin D they receive.
"Skin cancer is a very serious disease, and I don't want to minimize it, but at some point that extra minute you spend inside is costing you more vitamin D than it's helping you not get skin cancer," commented Slusky.
And as for those topping up vitamin D levels with supplements due to these concerns, Slusky and his colleagues also added that many women may not not be getting the full benefits from them, and a little sunshine is still best.
"Clearly if I'm going to the beach or going to spend all day outside, I need to put on sunscreen," Slusky said. "But spending 10 minutes outside without it may not be such a bad idea.
The study is due to be published in the upcoming issue of the American Journal of Health Economics.