The Best and Worst Sources of Calcium

We grow up hearing, “Drink your milk! You need it for strong bones.” While calcium is essential, milk isn’t the best source—and that may be a relief to hear for many of you who don't tolerate dairy well.

In this article, we’ll breakdown the best and worst sources of calcium, highlight plant-based foods that provide calcium, and discuss what to look for in a high-quality calcium supplement.

Calcium is best known for its role in building strong bones—about 99% of it is stored in the skeleton. But calcium’s importance goes far beyond bone health, playing a vital role in hormone release, nerve communication, and muscle function, including the heart.

Here's a key takeaway—if bone health is your goal, it’s important to know that calcium is just one piece of the puzzle. Bone strength depends on a combination of nutrients, lifestyle factors, and how well your body can absorb and use calcium—not just how much you consume.

The Myth About Dairy Products

The United States has one of the highest rates of dairy consumption, yet according to the National Osteoporosis Foundation about 54 million Americans have osteoporosis and low bone mass (osteopenia). The truth is bone health isn't dependent on how much milk or dairy products we consume. Even Harvard has challenged the idea that dairy is necessary for strong bones. In fact, many countries that consume very little dairy have some of the lowest rates of osteoporosis, and for most of human history we didn't consume dairy products.

Dairy isn’t well tolerated by everyone—about 65–70% of the world’s population has some degree of lactose intolerance and others react to the dairy proteins casein and/or whey. You can think of lactose intolerance as a spectrum and for many individuals symptoms are dose dependent or build up over time. For those affected by a dairy sensitivity or lactose intolerance, consuming too much, or any at all for some, can increase inflammation, which may negatively impact bone health. This isn’t to say you should avoid dairy entirely—if you tolerate it, incorporating plain yogurt, some cheese, or cottage cheese can be beneficial—but know that it’s not essential for bone strength.

Strong bones are primarily supported by lifestyle factors: regular movement, maintaining adequate vitamin D levels, eating a diet of real food, and limiting sugar, caffeine, alcohol and processed carbohydrates (which can all increase calcium loss).

Learn More: Dairy Intolerance: Causes, Symptoms, Solutions 

 Worst Calcium Sources: Fortified Foods and Calcium Carbonate

So, we covered why dairy foods and milk are not the best sources of calcium, especially if you don't tolerate dairy.

You may be wondering about those packaged foods that boast they have contain a lot of calcium.

Not so much, and here’s why.

Calcium Carbonate:

The added calcium found in orange juice, many breakfast cereals and even added to many brands of almond milk is calcium carbonate. Unfortunately, many calcium supplements also contain this same form of calcium. Calcium carbonate is the cheapest and least absorbable form of calcium available. In fact, large amounts of calcium carbonate can cause calcium to go into your soft tissues (including your arteries) and not your bones.

You read that right – even though you’re drinking added calcium in your fruit juices, your body isn’t able to absorb that form. What a waste!

Plus, orange juice is full of sugar. Although it’s natural sugar, drinking a 16-ounce glass of orange juice has just as much sugar as a can of soda and we know that sugar can increase calcium loss.

Forms that are more bioavailable include: calcium citrate, calcium malate, calcium glycinate, or MCHC.

Calcium Deficiency - Common Reasons to Supplement with Calcium

What are some symptoms of calcium deficiency? What areas of health do good sources of calcium support?

Take a look at this list of signs you may not be getting enough calcium:

Quick Recap

• Calcium is essential for bone health, but it’s only one part of the equation—absorption, lifestyle, other key nutrients and overall diet also matter.

• Dairy is not required for strong bones, and many people don’t tolerate it well; plant foods and fish with bones provide highly bioavailable calcium.

• Fortified foods and calcium carbonate are poorly absorbed and don't support bone health effectively.

• For a calcium supplement, the form matters significantly. If your supplement only lists calcium carbonate, consider switching to one that uses calcium citrate, calcium malate, calcium glycinate, or MCHC.

• Strong bones are best supported by regular movement, adequate vitamin D, limiting sugar and processed foods, and using well-formulated supplements when needed.

Online Class: Preventing Osteoporosis With Bone Building Foods

Learn which foods build bones and understand the factors that put your bones at risk.

Preventing Osteoporosis With Bone Building Foods

For more information on calcium, check out these resources: 

LISTEN: All About Calcium – Ask a Nutritionist - What calcium supplement should I take? Do I get enough calcium from my diet? Calcium is just for our bones, right? How much calcium should I take? Britni goes over all you need to know about calcium supplementation.

READ: Foods For Osteoporosis– want strong and healthy bones? Real food to the rescue! Find out what nutrients you need (calcium included) to help strengthen and protect your bones.

READ: Top Osteoporosis & Bone Health Supplements–our top recommendations on supplements to support your bones.

References

Harvard T.H. Chan School of Public Health. Calcium — The Nutrition Source. The Nutrition Source, Harvard T.H. Chan School of Public Health. Available at: https://nutritionsource.hsph.harvard.edu/calcium/ (accessed January 2026)

Hu L, Ji J, Li D, Meng J, Yu B. The combined effect of vitamin K and calcium on bone mineral density in humans: a meta-analysis of randomized controlled trials. J Orthop Surg Res. 2021 Oct 14;16(1):592. doi: 10.1186/s13018-021-02728-4. PMID: 34649591; PMCID: PMC8515712.