In our health-conscious society, we're all guilty of overanalysing our bodies every now and again. Feeling bloated? You probably have bowel cancer. Tired? According to the internet, you have bird flu.
However, it's important to remember that by constantly worrying about getting sick, we're a lot more likely to actually get ill, since stress is well known to weaken the immune system and leave us vulnerable to infection. But if you're stuck in a hypochondriac hole you simply can't get out of, don't worry, because the following should help quell your worries about one particular aspect of your body. Your nails.
Ever wondered why those weird white marks sometimes show up on your nails? You may have heard that they're caused by a calcium or zinc deficiency, but don't run out to the supplement store just yet. It turns out that the real cause is something a lot more benign.
The white spots often found on your nails are actually caused by a phenomenon known as punctate leukonychia, which is caused my minor trauma to the nail. A slight bump or knock will do it. The white marks don't typically appear on the nail for several months after the trauma, so it's possible you wouldn't remember how you got the mark at all.
The following video from YouTube boffins Sci Show explains punctate leukonychia in more detail, as well as other forms of nail marks that may have slightly more worrying causes. But if you're certain you haven't been poisoned by lead anytime in the recent past, I wouldn't stress about it too much.