You may recall a study I posted last month about severe vitamin D deficiencies among American moms and their babies that multiply an infant's risks of rickets. That very same lack of vitamin D may also be instrumental in the development of asthma among young children.

Researchers tracked the health and vitamin D intake of some 2,000 healthy and pregnant Scottish women and more than 1,200 of their children to determine if signs of asthma and other wheezing illnesses would occur by the time those babies reached age 5.

Interestingly, poor diets and the lack of vitamin D among mothers were the determining factors in whether their children suffered from asthma, totally independent of their smoking habits, maternal intakes of vitamin E, zinc and calcium and a five-year-old's own vitamin D intake.

The study misses the point, however, when it comes to the best source of vitamin D -- your body generating it naturally from safe, daily sunshine exposure -- in lieu of dietary solutions like fish, much of which contain unsafe levels of mercury future moms should avoid at all costs for the sake of their children. (At least, the accompanying editorial concedes sunshine is far more important than human diets and nutritional advisories that come with media reports are often outdated and misleading.)

All this makes great sense, considering measured doses of sunshine have already been proven to reduce asthma. If colder temperatures prevent you from getting that safe dose of sunshine, however, and you're consuming a high-taking cod liver oil to make up for it, be sure to have your blood levels checked frequently.