Kids Getting Rickets?
Adults with bone problems?
A lack of Vitamin D.
For one thing, in the developed western world more of us are spending more time indoors. Parents tend not to let their kids outside as much as previous generations did. They cite fears of perverts, and the dangers of much increased traffic. Their fears aren’t entirely groundless, particularly when it comes to the dangers of traffic.
Also, we hear time and time again about the danger of exposure to too much sun.
Most of tend to dover up a bit more, and lather on the sunscreen.
What about food?
There’s not a lot of foodstuff that contain much of it. Oily Fish, and food fortified with it, such as some milks.
Recently, it was suggested that we should go outside, in the full sun, for twenty minutes, before we apply any sunscreen. Is that a good idea?
It could be, except that there are so many factors involved. What kid of complexion do you have? Paler skin absorbs UV (which the skin converts to Vitamin D) a lot quicker than darker skin, as a rule. What time of day are you in the sun. It’s obviously more powerful at noon, than at sunrise or sunset. What part of the world are you in? The sun is often more powerful at lower latitudes (although those that live in the higher latitudes, will certainly testify to sunburn).
A team of scientists at the Norwegian Institute for Air Research have built a sunlight calculator for this purpose. It takes into account all the factors mentioned above, and from it you can work out how many minutes you need to stand outside without sunscreen to get your recommended daily dose of D.