Calcium is synonymous with strong bones and teeth — and dairy products, of course. But there’s a lot more to this mighty mineral. For one, it’s the most abundant mineral in the human body, making up 1.5 to 2 percent of your total body weight. Along with strengthening bones and teeth, calcium helps muscles move, blood clot, nerves carry messages and many other functions. Here, six quick and fun facts that will make you want to hit the dairy case.
Calcium keeps your heart pumping — literally
During each heartbeat, 3 billion heart muscle cells contract and then relax in order to pump blood through your body—and they can’t do it without calcium. Calcium particles have an electrical charge essential to the process. They enter the cell and bind to machinery inside, trigging contraction, then leave the cell to make it relax. In fact, during the contraction phase, cell concentration of calcium is ten times higher than during the resting phase.
Bones give up calcium when your blood needs it
Given calcium’s crucial role in keeping you alive, it’s no shocker your body works hard to keep levels constant. When they dip, a hormone signals your bones—which store about 99 percent of your body’s calcium—to release some of the mineral. It’s a good insurance policy for your heart and all the other functions that rely on calcium. But it can also be bad news for bones if you don’t get enough calcium in your diet to replace what was released to fortify bones—a process called remodeling that keeps your skeleton strong.
Your calcium requirements change as you get older
Adults younger than 50 need 1,000 mg a day, while women 51 and older (i.e. post-menopause) and men 71 and older need 1,200 mg a day, according to the National Institutes of Health. Why the change? Estrogen, for one. It plays a key role in keeping bones strong, so when levels plummet after menopause, bones get weaker. Increasing calcium may help protect them. Second, as you move into your 70s, your body absorbs less calcium from food, so upping your intake helps compensate.
Dairy is one of the best ways to get calcium
Naturally high in calcium, dairy foods are an easy way to get what you need. But it’s also not the only way—i.e. you don’t need to OD on dairy to get your fill. Rather, aim for a mix of dairy and other foods rich in both calcium and other nutrients. Here’s how some common foods stack up.
- 1 cup cow’s milk: 300 mg
- 6 oz. low-fat yogurt: 310 mg
- 6 oz. Greek yogurt: 200 mg
- 1 oz. cheddar cheese: 205 mg
- ½ cup ice cream: 100 mg
- 3 oz. sardines 370 mg
- 1 cup cooked broccoli: 180 mg
- 1 cup raw arugula: 125 mg
- 1 cup chickpeas: 80 mg
- 1 oz. almonds: 80 mg
- 1 orange: 55 mg
- 1 cup fortified OJ: 300 mg
More calcium isn’t necessarily better
Remember how good your body is at regulating calcium in your blood? The same is true for your body overall. For example, if you go on a dairy binge and get loads of calcium, a different hormone tells bones to hold onto what they’ve got, plus signals the kidneys to release more into the urine for disposal. If you’re worried about getting enough, on the other hand, talk to your doctor; studies suggest supplements may not prevent fractures in older women and could increase your risk of kidney stones and heart attack.
Vitamin D and calcium are BFFs
Your body can’t absorb calcium with vitamin D, which is essential for making the hormone calcitriol. Calcitriol increases production of proteins in the gut that help the body absorb calcium and increase stores of it in bones. Known as the sunshine vitamin, vitamin D is produced when skin is exposed to sunlight. But you can also get it from fortified dairy and other foods, including some seafood (tuna, sardines) and supplements.