3. You’re 50 or Older
As you get older, physiology and preferences work against your vitamin D levels. For starters, your kidneys become less effective at converting the vitamin into a usable format for your body. Concurrently, your skin doesn’t synthesize enough vitamin D from sun exposure. A study showed that seniors who got regular sun exposure produced 75% less vitamin D than younger adults. However, most Fifty Plussers prefer to spend the majority of the day indoors and out of the sun, so their percentage is even lower. Your skin does not get the vitamin D benefit from sunshine unless you’re actually in the sunshine. Behind a window or sitting in a hot car does not count. You’ll just feel hot.
4. You’re Overweight
If you are overweight, you are at greater risk for a deficient amount of the vitamin that fights infection, absorbs calcium and maintains a healthy immune system. The reason is not conclusive, but science seems to say that because vitamin D is fat soluble, there is much more body fat to absorb the vitamin in an obese body. That spreads it quite thin. Alternatively, the vitamin could get diluted throughout the body, and this dilution shows up as a deficiency in people who are overweight because of the ratios. Either way, enough vitamin D is not finding its way to the bloodstream. And for overweight folk whose main source of vitamin D is the sun, as the bodyweight increases, the surface area of the skin that gets sun does not, so the body is not absorbing enough sun for the increased weight.