Surprising Things You May Not Know About Calcium
WHAT DOES CALCIUM DO IN YOUR BODY?
You probably know that calcium is needed to build strong bones. In fact, 99% of the calcium in your body is stored in your bones and teeth. Bone development increases rapidly at the start of puberty and peaks when teens reach their full height, and continues for up to four years. By the time someone is a young adult, they have reached their “peak bone mass,” which is linked to bone strength. After this point, it’s important to continue to supply your bones with a steady source of calcium to help maintain healthy bones and prevent osteoporosis. Why does this matter? The calcium in your blood is tightly controlled. This means if you don’t get enough calcium from food every day, your body will take it from your bones. And if calcium is in short supply for a long period of time, your bones will get weak and more likely to fracture. That’s why it’s important to eat calcium-rich foods every day throughout your life. What else does calcium do? Aside from building bones, calcium is needed to keep your heartbeat and blood pressure normal. As well, calcium helps your muscles contract and relax, and your nerve cells communicate. It’s also crucial in helping your blood clot.
HOW MUCH CALCIUM DO YOU NEED EVERY DAY?
The amount of calcium you need depends on your age and whether you’re male or female. According to Health Canada, many Canadians are not getting enough calcium from the foods they eat.1 Make sure you are not one of them.
|AGE||MALE (mg)||FEMALE (mg)|
HOW MUCH CALCIUM IS ACTUALLY ABSORBED?
While some foods contain calcium, you might not actually be getting as much from them as you think. Why? Because the body doesn’t absorb calcium from all foods in equal amounts. Milk, cheese and yogurt naturally contain calcium that is easily absorbed by the body. The same applies to calcium in broccoli, bok choy and kale. However, the calcium found in other plant-based foods is generally not as well absorbed. This is particularly true for rhubarb, Swiss chard and spinach, which contain a high level of oxalate that binds to calcium and prevents its proper absorption. While these foods are nutritious, you can’t count on them for calcium.
CALCIUM CONTENT OF SOME COMMON FOODS3
|FOOD||SERVING SIZE||CALCIUM (mg)|
|Milk (whole, 2%, 1%, skim)||250 mL (1 cup)||310|
|Cheddar cheese||50 g (1.5 oz)||337|
|Mozzarella cheese||50 g (1.5 oz)||288|
|Yogurt, plain||175 mL (3/4 cup)||272|
|Yogurt, flavoured||175 mL (3/4 cup)||206|
|Greek yogurt*||175 mL (3/4 cup)||170-500|
|Kefir, plain||250 mL (1 cup)||267|
|Bok choy||125 mL (1/2 cup)||84|
|Kale||125 mL (1/2 cup)||49|
|Broccoli||125 mL (1/2 cup)||33|
|NUTS AND SEEDS|
|Almonds||60 mL (1/4 cup)||97|
|Sesame seeds||60 mL (1/4 cup)||23|
|Edamame||125 mL (1/2 cup)||138|
|White beans||125 mL (1/2 cup)||85|
|Red kidney beans||125 mL (1/2 cup)||26|
|Hummus||30 mL (2 tbsp)||12|
|Canned sardines with bones||75 g (2.5 oz)||286|
|Canned salmon with bones||75 g (2.5 oz)||212|
|Calcium-fortified plant-based beverages†||250 mL (1 cup)||318|
|Tofu, regular, firm or extra firm|
(prepared with calcium sulphate)‡
|85 g (3 oz)||171|
*The calcium content of Greek yogurt varies according to the brand. Check the label to see how much you’re getting.
† Some plant-based beverages are fortified with calcium. The value presented is an average. However, they may not be a reliable source of calcium. The added calcium may not be as well absorbed as the calcium naturally found in cow’s milk and it tends to settle at the bottom of the container, even after vigorous shaking.
‡ The calcium content of calcium-set tofu varies according to the brand and depending on the type of tofu. Check the label to see how much you’re getting.
CALCIUM: FOOD OR SUPPLEMENTS?
It is recommended to obtain calcium through the diet.4, 5 The advantage of foods, and milk products in particular, is that in addition to calcium, they contribute other nutrients that are important for bone health.
- Health Canada. 2016. Evidence review for dietary guidance: Technical report 2015.
- Institute of Medicine. 2011. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academy Press.
- Health Canada. 2015. Canadian Nutrient File. https://food-nutrition.canada.ca/cnf-fce/index-eng.jsp. Accessed March 4, 2019.
- Osteoporosis Canada. Calcium Calculator. https://osteoporosis.ca/bone-health-osteoporosis/calcium-calculator/#results. Accessed June 20, 2019.
- National Osteoporosis Foundation. Calcium/Vitamin D. https://www.nof.org/patients/treatment/calciumvitamin-d/. Accessed June 20, 2019.
- International Osteoporosis Foundation. Calcium. https://www.iofbonehealth.org/calcium. Accessed June 25, 2019.