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| Sunday, 24 October 2004 |
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Junior Observer |  |
| News Business Features Editorial
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Act now for strong
bones If you're like most kids, you probably think you'll never get old. Achy joints, failing eyesight, heart attacks: these are things you won't have to deal with for a long time, right? So why worry now? As it turns out, the choices you make now can make a big difference in how you feel later in life. I recently learned this lesson the hard way. It started with an injury: a cracked shinbone caused by too much running on hard pavement. My doctor suggested a bone scan, which showed that my bones are weaker than average. I don't have osteoporosis, a disease that causes older people to shrink in height and break bones easily. But I'm close. For me, the diagnosis was a scary wake-up call. I'm just 27 years old, but already I'm worried about things that normally happen only to women more than twice my age. Will I break my hip if I slip on a patch of ice? Is it safe for me to go skiing, lift heavy boxes, play Ultimate Frisbee? Perhaps what upsets me most is the realization that I might have avoided all of this if only I had thought ahead earlier in life. Childhood and adolescence are the most important times to build strong bones. For you, there's still time. Bones are amazing. They're hard but flexible, and they're lightweight but tough. Without bones, we'd be just puddles of skin and guts. An adult person has 206 bones in his or her body. The outer layer of a typical bone is made of a hard material honeycombed with tunnels. This web of hollow pipes allows a bone to be strong and light. It also allows the passage of nutrients and waste. A protein called collagen gives a bone its elasticity. Chemicals known as calcium salts make a bone hard. But, even though our bones support us, they're easy to ignore. Unlike a cut or bruise, a weak bone isn't visible or painful. Silent disease Osteoporosis is sometimes called a silent disease. People often don't realize they have it until it has progressed so far that they break bones while doing ordinary things, such as walking down stairs or lifting heavy objects. Osteoporosis happens mostly to older people. But I'm not the only woman in her 20s with weak bones. Increasingly, scientists are finding that weak bones are a problem in teenagers and even younger kids. That's especially troubling because youth is the critical time for bone growth. If you've ever seen a skeleton in a museum, you might think that bones are dead. In fact, bones are living tissue. They reshape and rebuild themselves many times as you grow and age. The cycle of building and breaking down bone changes over a person's lifetime. Bone-building is fastest during the first three years of life and again during adolescence. By the time you're in your 20s, the tissue in your bones is about as tightly packed as it's going to get. Once you get to be about 35 years old, bone tissue gets broken down more quickly than it's replaced. This means that bones tend to lose tissue, and the bone density goes down. That's when osteoporosis usually becomes a concern. And it's a bigger risk for women than for men. Doctors urge kids to get plenty of calcium, the mineral that makes bones strong. Calcium is also essential for keeping nerves, blood, and muscles healthy. When you don't take in enough calcium, your body takes calcium out of your bones, which weakens your bones even more. Unlike milk or fortified juice, a soft drink doesn't provide calcium for helping to build strong bones. Junk food has few nutrients. It also fills you up, so you don't eat enough of the good stuff. Getting enough exercise is also crucial. Walking and lifting weights, in particular, are great for building muscles that support and strengthen bone. Playing soccer, tennis, or basketball are also good options. The changes are small, but the payoff could be big. You might even be amazed at how good it feels to take care of your bones. Support them, and they will support you for many years to come. Science News for Kids ###### Tomatoes vs. mosquitoes Could tomatoes know something about repelling mosquitoes that we don't? There are two things that can ruin any good summer day: sunburn and mosquito bites. While sunscreen is still the best protection from the sun, scientists in North Carolina, USA may have found something better than those stinky sprays to protect us from mosquitoes. Where? In tomatoes! While looking at the chemical in mosquitos' stomachs that tells them when they are full, he noticed something strange. That "stop-eating" compound looks a lot like a chemical compound in tomatoes. Like many plants, tomatoes contain a natural chemical compound that repels insects. Roe decided to see if, when extracted from the tomato, the tomato compound would still repel insects. To test the tomato compound, Roe applied it to the skin of several volunteers. When exposed to mosquitoes, 91 per cent fewer mosquitos landed on the volunteers who wore the tomato compound than those who didn't. Even more impressive, they weren't bitten by a single mosquito! This is even better than most current insect repellents, which contain the chemical DEET. In the same test, DEET was only able to reduce mosquito landings by 78 per cent. A biotechnology company in Durham, North Carolina is now trying to produce the tomato substance as an insect repellent. So far, it seems to work against many pests - ticks, fleas, cockroaches - as well as mosquitoes. Who knew tomatoes could trick so many pests? Smithsonian Magazine Kids' Castle |
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