If you, like me, have lived your life so far being completely baffled about why you get white marks on your fingernails every now and then, despite having milk in your cereal every morning, then we're about to solve the mystery.
Because while most people have always been told that these white spots mean you're not taking in enough calcium, it turns out that's not necessarily the case – so sadly this isn't an excuse to crack out a daily cheeseboard in the 'interest of your health' (although wow, how great would that be?).
Although in some cases the white spots might indicate a deficiency of some sort in your diet, there's actually a much more common and simple explanation for so-called milk spots: you've bumped your nail on something and created a minor trauma.
The official scientific term for those white lines is 'punctate leokonychia' (but we prefer the more casual 'milk spots'), and they most commonly seem to arrive following 'trauma' to the nail, which can actually be so minimal you don't even remember it happening, the sensitive little things. So you see, it's no big deal really.
However, if your entire nail has turned white – then that's definitely something you ought to get checked out. "If people have low protein levels in their bloodstream it [often] causes the whole nail to go white," explained Dr Dan Baumgardt, a GP and lecturer in neuroscience and physiology at the University of Bristol, when talking to the BBC. "We tend to associate that with people who've got liver disease, so things like cirrhosis of the liver, perhaps as a result of alcoholism."
Oh, and there is one other potential explanation for white lines too: a fungal nail infection, or a previous illness that you're likely already more than over.
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When your body fights off infections it needs to devote more energy to that and so it slows down the growth of unimportant things, like nails.
Said white lines then appear as a kind of indication that growth has been paused, but the good news is that the milk spots take so long to appear, you'd already know you had the fungal infection or have been poorly. So you can chill out before you've convinced yourself your big toenails is about to rot away.
Right, that's your science lesson over, you can get back to YouTubing cats being scared of cucumbers or whatever other important task you were doing before.
This article is not intended to be a substitute for professional medical advice or diagnosis. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Cat is Cosmopolitan UK's features editor covering women's issues, health and current affairs. news, features and health. The route to her heart is a simple combination of pasta and cheese (somewhat ironic considering the whole health writing thing), and she finds it difficult to commit to TV series so currently has about 14 different ones on the go.
