Get Enough Vitamin D From Sunlight With This App
Our skin can convert 7-dehydrocholesterol to vitamin D with a little help from sunlight. If you don’t get enough sun, it’s okay, you can also get your vitamin D from food. But you might be wondering – how much sunlight is enough?
Dminder (free, iOS / Android) is the app that will do it for you. The calculation is not as easy as it is said that you have to spend so many minutes in the sun, because it is not just sunlight that will help you make vitamin D, but specifically the same UVB rays that cause sunburn. We only get a significant amount of UVB rays when the conditions are right: the sun should be shining directly on you. If you live near the equator (or even some parts of the southern US), this includes the middle of each day. The rest of us get our best vitamin D in the middle of the day in the summer.
Your UV-B needs also depend on factors such as:
- Your height
- How dark your skin is and how easily you tan
- How old are you
- How many clothes are you wearing
- And, of course, how much vitamin D do you eat.
Most of us are probably okay, so if you’re not worried about your vitamin D status, there is no need to start. But if you’re curious, you can enter your recent vitamin D test result (optional) and the amount of vitamin D you normally get in your diet. (Dminder does not calculate vitamin D intake from foods, but many nutritional tracking apps can help you figure this out.)
It then uses your location and time of day to help you figure out how much D you can get from the sun. In my city, on a cloudy day, it would take me 20 minutes in jeans and a T-shirt to replenish my vitamin reserves. But I burn out if I’m away for more than 10 minutes, so the app will helpfully tell me it’s time to get in. Perhaps I can eat salmon fillets instead ( 425 IU per three ounce serving ).