Calcium Spots?

I was always told that the white spots that occasionally appeared

on my nails were due to a calcium deficiency. So naturally when

I saw a "calcium spot" on my nail, I got me a large glass of milk.

My roommate noticed that I was drinking milk, something I never

do, and asked me why. I told her about the spots and she argued

that her mom told her they appear when you’ve had too much

calcium. So I researched it and apparently, neither was the case.

Leukonychia is the medical term for the white discoloration of

the nail. There are three different kinds of leukonychia but the

most common is the appearance of white spots on the nail. This

type is also the least serious(2). These spots generally occur

when there has been trauma to the matrix or base of the nail.

The matrix is the root of the nail and extends several millimeters

into the finger. The root contains no melanin and appears as a

white crescent under the finger nail(1). The nail bed is also a part

of the matrix. When this matrix is injured white spots will appear

similar to the way a bruise would appear on your skin (3).

Though most cases of leukonychia are not serious, spots that

remain for longer than 8 months, the time it takes for the nail to

re-grow completely, could be caused by a more serious

condition. One common cause is a zinc deficiency(3), so my

family was almost correct, they just had the wrong element.

References:
1. http://dermatology.about.com/cs/nailanatomy/a/nailanatomy.htm

2. http://www.nationmaster.com/encyclopedia/Leukonychia

3. http://www.wisegeek.com/what-causes-white-spots-on-fingernails.htm