Until What Age Can You Keep Building Bone Density?

Got calcium? You'll know from fourth-grade science that calcium is the mineral mostly found in the skeleton and teeth — but you may not have been warned about what happens as the body ages. Calcium depletion is a pretty natural process that shouldn't panic you, as it happens to every person as they get older, but it's also surrounded by a host of pretty bizarre myths and misconceptions. For instance, bones aren't 100 percent calcium: they're actually compositions made of collagen and calcium carbonate. We grow more collagen-heavy bones initially as fetuses, then have them replaced by calcium-strong ones as we grow. That means you've already grown two skeletons! High five!

Calcium depletion is basically the loss of density in the calcium carbonate in your bones. They don't actually become "spongy," just more brittle and delicate — (though, funnily enough, Stanford University has been investigating using real sea sponges and coral as "scaffolds" to rebuild damaged, aging bones). Calcium depletion is natural, but can lead to conditions like osteoporosis if the bones aren't initially all that strong or if the process accelerates too fast.

Calcium isn't just in the body to work on our bones, either. It's used to stabilize our blood pressure and heartbeat, and it's a vital part of our normal blood clotting process and muscle contractions. So lower levels of calcium in the body generally are something to be aware of. Here are eight facts to bust the myths about calcium depletion, and what you can do to protect yourself.

1. You Can Only Build Bone Density Until About Age 30

We don't keep building up bone mass throughout our lives, unfortunately enough. We gain the most bone mass during puberty, when we're experiencing growth spurts; we get 90 percent of our bone density by the time we're about 18. But we continue to pack in the calcium density until we're 30, when our bones are the strongest they'll ever be.

The mass of the bone has two modes: old bone removal and new bone growth. After the first 30 years of our lives, we switch increasingly into the first mode, and less and less bone is made to replace it. The result? Depleted bones. Feeling old yet?

2. Our Bodies Don't Produce Calcium On Their Own

This is a pretty crucial thing to understand: there's no natural mechanism in the body that makes calcium out of nothing. Everything in our body that's calcium-based has to be supported by what we eat and drink.

The recommended daily dose of calcium for adults is 700mg, but it's rich in a lot of foods, from Chinese cabbage to almonds. A note about soy milk, though: if you're consuming it or rice milk instead of animal milk, you need to be cautious about its calcium content. Calcium in fortified soy and almond milk can often "separate" and drift to the bottom of the container rather than remaining incorporated in the milk — so you may be getting less calcium than you thought. Shake that carton and eat plenty of those dark, leafy greens though, and you'll be just fine.

3. Black Women Often Have Stronger Bones Than White Women

This is an interesting and slightly puzzling fact about bone density. Not only is there a difference between genders (men have greater bone density than women, particularly during puberty), but there's a racial disparity in bone strength between African American women and white women.

Nobody's quite sure why, but a 2007 study found that 10 out of every 1000 white women are likely to have hip fractures (a common side affect of weak bones), as compared to four in every 1,000 black women. And it gets more pronounced as we get older: 16.3 percent of white women are likely to get a fracture after age 65, compared to 5.3 percent of black women. The differences exist between white and black men, too. It looks as if racial genetics might play an important role in your bone health as you get older.

4. Menopausal Women Need To Increase Their Calcium Intake

The biggest cause of calcium deficiency and bone loss in women? Menopause. It's been proven repeatedly by scientists that post-menopause, bone density dips seriously. It seems as if the hormone upheaval caused during the menopause has knock-on effects on the process of maintaining bone density in the skeleton and teeth, something doctors recommend you combat by taking 1500 mg of calcium daily during and after menopause.

It's not just bone density, either. A general loss of calcium in the body can cause all manner of upsetting problems, from memory loss to muscle spasms and tingling in the nerves, because of the role calcium has in muscle function and a healthy nervous system. Lower levels of calcium mean that various bits of your body, from the brain to the nerves, start to function less efficiently, sometimes drastically.

5. Calcium-Rich Toothpaste Has Its Own Risks

We sometimes forget that teeth are themselves made of bone — but they are, and they degrade in response to aging and menopause, too. One solution that's been posed is calcium-rich toothpaste, which contains a liquid calcium designed to "plug" gaps left by degrading enamel and calcium in the teeth. The problem? This can build up in the mouth and result in blockages and general nastiness.

This is something I have personal experience with: a calcium-rich toothpaste led to calcium build-up in one of my salivary glands, blocking it entirely. It's apparently not that common a side effect, but I don't recommend it, as it feels as if you've been shot in the face. Use at your own risk.

6. You Can Reduce Bone Loss By Exercising More

The process of maintaining bone strength isn't just about consuming huge amounts of cheesecake (as we'll see in a minute, calcium overdoses exist). Exercising and putting pressure on the bones is actually a key part of maintaining their strength and ability to cope with stress; it's one of the big recommendations to stave off osteoporosis and damaged bones in old age.

Walking is actually one of the easiest and safest ways to maintain bone density, but jogging and other weight-bearing exercises work too. Unfortunately, exercise can't help you build bone density — but maintaining it is key. If you exercise too much, you'll degrade the bone, though, so strike a healthy balance.

7. Calcium Deficiency Doesn't Actually Cause White Spots On Your Fingernails

If anybody at school ever pointed to white spots on your fingernails and screeched that you had a calcium deficiency, they were wrong. White spots on the fingernails aren't associated with body deficiencies in minerals (no, not with zinc, either). They're more likely to do with something that happened to the nail as it was forming: they're often signs of mild trauma, whether to the cuticle or to the nail itself. Don't let your mom tell you any different.

8. You Can OD On Calcium

If this is all freaking you out and you want to cram yourself with as much calcium as humanly possible, don't. Calcium overdose is a definite thing. People have been known to take way too many calcium supplements or live on a far too calcium-rich diet, and the body's response isn't to give you bones as strong as your resident superhero. It's diarrhea, vomiting, heart and muscle problems, pain in your bones, and a basic disruption of all the functions that normal levels of calcium help to maintain.

If you're concerned you're not getting enough calcium, go to your doctor and talk to them about what to do. Don't just start cramming yourself with supplements and slathering your face with calcium toothpaste. It won't end well.

Images: Tove Paqualin/Flickr, Giphy