Milk products, such as milk, cheese, and yogurt, are the main source of calcium in the diet.1,2,4 Milk and milk products contain good amounts of calcium that has good bioavailability, meaning that it is easily accessible to the body.3 In contrast, most plant sources contain lower amounts of calcium and/or calcium that’s less bioavailable, meaning it’s less available to the body.3
While milk products aren’t the only source of calcium, enjoying them as part of a healthy diet makes it easier to meet our needs for calcium and many other nutrients needed for bone health.
In practice
Milk products, such as milk, cheese, and yogurt, are naturally rich in calcium that our body can absorb. Including dairy foods as part of a healthy diet makes it easier to meet calcium needs.
- Milk products are a reliable source of calcium with good bioavailability.
- Most plant-based foods contain less calcium and/or compounds that limit calcium absorption.
- Calcium works along with many other nutrients in dairy foods to support strong bones.
- Three daily servings of milk products go a long way to help meet daily calcium needs.
How milk products help meet calcium needs
The Institute of Medicine established recommended daily calcium intakes for Canadians 4 years of age and older ranging from 1,000 to 1,300 mg.5 These recommended daily intakes, known as the Recommended Dietary Allowances (RDAs), vary according to age and sex group. The RDAs for calcium are based on the levels needed for calcium balance and bone health.1
Recommended Dietary Allowances (RDAs) for calcium
| Age (years) |
1-3 | 4-8 | 9-13 | 14-18 | 19-50 | 51-70 | 71+ |
| Females (mg) |
700 | 1000 | 1,300 | 1,300* | 1,000* | 1,200 | 1,200 |
| Males (mg) |
700 | 1000 | 1,300 | 1,300 | 1,000 | 1,000 | 1,200 |
*Including breastfeeding and pregnant.
A typical serving of milk products, such as a 250 mL glass of milk, a 50 g piece of cheddar cheese, 175 mL of yogurt contains approximately 300 mg of calcium that is well absorbed. This represents about one quarter to one third of the daily recommended intake (RDA) for calcium for most Canadians 4 years of age and older. That’s why enjoying three typical servings of milk products a day can go a long way to help Canadians meet their daily calcium needs.
How plant sources compare to milk products
It’s important to understand that calcium is not absorbed to the same degree in all foods. Two key compounds found in many plant-based foods, oxalates and phytates, bind to and inhibit calcium absorption.5 This reduces calcium bioavailability, such that the Institute of Medicine considers plant-based foods with high levels of these compounds poor sources of calcium.5
Oxalates found in beans and some leafy green vegetables, like spinach and rhubarb, limit calcium absorption from these foods. For example, one would have to eat 8 cups of spinach for one’s body to obtain the same amount of calcium as from a single cup of milk.6 The same is true of phytates found in whole grains, wheat bran, beans, nuts, seeds, and soy isolates.
Although certain dark green vegetables, such as broccoli and kale, have higher absorption rates, they contain less calcium.6 For example, one would have to eat more than 2 cups of broccoli for one’s body to obtain the same amount of calcium found in one cup of milk.6
Wondering about calcium bioavailability and common foods? Learn more here.
The added advantage of dairy foods
The International Osteoporosis Foundation recommends foods as the preferred source of calcium and highlights that, “Milk and dairy products are the most readily available dietary sources of calcium. Dairy foods have the additional advantage of being good sources of protein and other micronutrients important for bone health.”1 In fact, milk products are an important source of protein as well as six key nutrients that contribute to bone health that many Canadians don’t get enough of, including calcium, magnesium, potassium, zinc, and vitamins A and D.7,8
Enjoying three daily servings of milk products makes it easier for most people to meet their daily calcium needs for bone health.
Looking for key evidence-based information about bone health, calcium, and milk products? Discover our factsheet for health professionals.
References
1. International Osteoporosis Foundation. Calcium. www.osteoporosis.foundation. Accessed June 25, 2021.
2. Weaver CM et al. The National Osteoporosis Foundation’s position statement on peak bone mass development and lifestyle factors: A systematic review and implementation recommendations. Osteoporos Int 2016;27:1281-1386.
3. Weaver CM and Plawecki KL. Dietary calcium: adequacy of a vegetarian diet. Am J Clin Nutr 1994;59:1238S-1241S.
4. Health Canada. Evidence review for dietary guidance: Technical report 2015. Ottawa, Ontario: Health Canada. 2016.
5. Institute of Medicine. Dietary Reference Intakes for calcium and vitamin D. Washington, DC: National Academy Press, 2011.
6. Weaver CM et al. Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr 1999;70(suppl):543S-548S.
7. Health Canada. Evidence review for dietary guidance: Summary of results and implications for Canada’s Food Guide. Ottawa, Ontario: Health Canada. 2016.
8. Wallace TC et al. Dairy intake and bone health across the lifespan: a systematic review and expert narrative. Crit Rev Food Sci Nutr 2020;1-47.
