5 Things You Never Knew About Your Nails

Aside from the occasional manicure, broken fingernail or stubbed toe, most of us tend to take our nails for granted, not giving them much beyond a passing thought.

But they might be more complicated than we think. For starters, nails are made up of more than just the part we paint over with polish. "The nail plate (hard part of the nail) grows out from the matrix (the root) in a shape something like an ocean wave," says Jessica Krant, M.D., a board-certified dermatologist, founder of Art of Dermatology and an assistant clinical professor of dermatology at SUNY Downstate Medical Center in New York City. "The white portion of the nail at the base (most easily visible at the thumbs) is called the lunula (little moon). This is the end of the matrix showing."

Intrigued? Here are 15 more things you might not know about your nails:

* Fingernails grow an average of 3.5 millimeters per month.

That's just over a tenth of an inch. And nails on your dominant hand tend to grow faster. Toenails, on the other, uh, hand, grow an average of 1.6 millimeters a month,according to the American Academy of Dermatology.

* White spots on your nails don't indicate a calcium deficiency.

"Calcium deficiency causing white spots on nails is the most common myth, followed by zinc deficiency. The truth is that white spots are common and harmless and don't indicate any specific vitamin deficiency at all," Krant says. "Most likely they are signs of previous trauma to the nail plate (the hard part of the nail) or the matrix (the source of the nail plate, which is located underneath the cuticle under the skin). Just like folding or denting a piece of clear plastic leaves a white spot, so does pressure or trauma to the nail."

*Nails are made out of the same stuff as hair.

Both nails and hair are made up of keratin, just put together in a different way, Krant explains. And that means the same foods that are good for your hair are good for your nails. "A varied diet rich in vitamins, antioxidant fruits and veggies, protein, and minerals is key for healthy nails and hair," she says. "Keratin is a protein, and healthy oils and fats are also needed to keep the skin, hair, and nails moisturized and strong."

*Men's nails grow faster than women's nails.

The possible exception, according to the American Academy of Dermatology, is during pregnancy.

*Nails are what separate the primates from the mammals.

While most mammals have claws to help them with daily tasks, fingernails are something that distinguish primates (including humans) from the rest of the group,