Calcium is a mineral — a natural substance found in rocks, soil, and many foods. It is the most abundant mineral in the human body, and about 99% of it is stored in your bones and teeth. Calcium is what makes your bones hard and strong enough to support your weight and protect your organs. Without enough calcium, bones become weak and can break more easily. Your body cannot make calcium on its own, so you need to get it from the foods you eat every day.
Children and teenagers actually need more calcium than most adults do. Kids ages 9 to 18 need about 1,300 milligrams of calcium every day, while adults only need about 1,000 milligrams. This is because childhood and the teenage years are the critical period when your body is building most of its bone density. About 90% of your peak bone mass — the strongest your bones will ever be — is established by the time you turn 18. The calcium you consume now is like making deposits in a bone bank that will benefit you for the rest of your life.
Dairy products like milk, cheese, and yogurt are some of the best sources of calcium — one cup of milk contains about 300 milligrams. But dairy is not the only option for getting enough calcium. Calcium-fortified plant milks made from soy, almond, or oat can provide similar amounts. Leafy green vegetables like kale and broccoli contain calcium, and so does tofu that is made with calcium sulfate. Canned salmon with the soft, edible bones is another surprisingly good source of this important mineral.
Even if you eat plenty of calcium-rich foods, your body cannot absorb the calcium properly without vitamin D. Vitamin D acts like a key that unlocks the door for calcium to enter your bones. Your skin makes vitamin D naturally when sunlight hits it, and you can also get it from foods like eggs, fatty fish, and fortified milk. Without enough vitamin D, calcium passes right through your body without being used. This is why many doctors recommend that kids spend time outdoors and eat vitamin D-rich foods along with their calcium.
Eating calcium is only part of the story — you also need to move your body to build strong bones. Weight-bearing exercises like walking, running, jumping, and dancing send signals to your bone cells telling them to lay down more mineral and grow stronger. When you jump rope or play basketball, the impact of landing stimulates your bones to become denser and tougher. Swimming and cycling are great for your heart and muscles, but they do not strengthen bones as much because your body is supported by water or the bike. The best approach is to combine calcium-rich foods with plenty of active, on-your-feet exercise.
When your body does not get enough calcium from food, it starts to pull calcium out of your bones to use for other important jobs like keeping your heart beating and your muscles working. Over time, this weakens bones and can lead to a condition called osteoporosis, which means “porous bones.” Osteoporosis affects about 10 million Americans, and approximately 34 million more have low bone density. Bones with osteoporosis become so fragile that even a minor bump or fall can cause a fracture. While osteoporosis mostly affects older adults, the seeds of the disease are planted during childhood when bones are still developing.
The bone mass you build during childhood and your teenage years largely determines how strong your skeleton will be as an adult. Think of it like building a savings account — the more calcium you deposit now, the more you will have to draw from later in life. After about age 30, your body slowly starts to lose more bone than it builds, so the stronger you start, the better off you will be. Making calcium-rich foods a regular part of your meals, getting enough vitamin D, and staying physically active are the three keys to building bones that will last a lifetime. Every glass of milk and every game of tag you enjoy today helps build the strong skeleton you will rely on as an adult.
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